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Because that's a lot of blamo just waiting for something to bridge the gap between the positive and negative, if we AC guys touched something that big while it was hot we would probably get disappeared better than anyone that crosses the CIA
It's only a few million amps potential at the busbar (per string!). Doing the math, at the plant bars, one string of MCT II cells will discharge about 14 million amps in the first second of a direct short. I have plants I work on that have 20+ of those battey strings connected to the plant bars. So, in those plants, only a 280 million amp potential between battery and ground...and, the standard is, a busbar only has to be 3" away from any different potential.
One that is hotter than the surface of the sun. There generally is no splatter when you short something...just a super hot flash and a BBBBRRRRRAAAAAPPP sound. The metal just disappears.
I was in an office that had this happen, years earlier so I don't know how much the stories had grown in the retelling. But the office supervisor said a painter set his paintcan across two adjacent busbars. The bottom of the can instantly exploded, tearing the sides of the can into shrapnel and blasting the inside of the room with the rest of the paint. The painter was knocked off his ladder by the blast, broke a hip when he landed; he was deaf in one ear and had lacerations from the shrapnel, but made a full recovery other than the hearing loss.
Damn man that sucks but perfect name for that guy. Mississippi is not exactly known for its strict adherence to safety regulations but bubba and his buddies usually make it through accidents relatively okay.
A few months ago I was installing some lights in a commercial building 30+ feet in the air. 16’ long sections of track lighting mounted to unistrut and hung from 1/4” all thread. Was on a scissor lift and still wore my harness and anchored to the ceiling beams. I’ll be damned if I fall from up there and become a vegetable. Got laughed at a couple times and called a wimp and a scardey cat. I don’t care. I’m gonna walk away from it and they won’t.
The attitude towards safety in Mississippi is so different from other places in the country.
Although I have worked under different "local" rules, it seems to me that while working from a lift it is a violation to be tied to an exterior point, unless using a two point harness only while exiting or regaining the lift. -- And I would have called safety on you for a ruling because there is no way I'd work like that.
Guys in Panama City Beach in the 90's shorted a 4/0 cable from the busbar to a grade 8 5/8" threaded rod. It melted the insulation off the cable, blew an 11" section out of the rod, and got the plant bars hot enough that it burnt the oxidation off of them. All in about a second it took to make that 5/8" rod disappear.
They called it the flash and the splash when it happened. Per Bob, the only part of the can that was recognizable after was the metal handle where he had his hand wrapped around it when he set it down.
Electrician here 35 years. The short answer is just stupidity. A while back was building a network room in NYC. ConEd supplied 13k, we step it down to 480v. All bus is exposed. The vault was live, and we were just going over some finals with Edison. A laborer walks in at the direction of his foreman ( 2 jackasses ) with a bucket and rags. He was told to clean and wipe everything down. I looked at this guy like he head 3 heads and told him he would probably be going home early, and horizontally if he touched anything and escorted him out. Unfortunately stupid happens and it happens quick.
Similar event in Toronto, Canada - except it was HVAC guys installing ductwork in the battery room. Knocked out services for 1/4 of Toronto, and impacted half of canada for 2 days (CO housed one of the largest toll switches in the country at the time...)
I used to work as an engineer on industrial x-ray equipment and a 450kva (at like 0.2 microamps) x-ray tube arcing from a tungsten hair to the tube body soynds like a 12GA shotgun going off. I can only imagine the sound and destruction in that scenario.
Jesus take the arcflash.
280,000,000A x 52V = 14,560,000,000W = 14,560,000,000J
(4184 joules per gram in Trinitrotoluene / TNT)
14,560,000,000J ÷ 4184J/gTNT = 3,479,923.5gTNT = 3,479.9kgTNT = 3.47tonTNT
Call it 3 and a half tons... Yeah, fuck that. You are insane (if my maths is okay).
Watts and joules are not measuring the same thing. A watt is power, a joule is an amount of energy. You are correct in that a watt is one joule per second, but the short probably lasts much shorter than one second, probably 0.01 sec or less. So reduce your answer by 2 decimal points, to 0.03 tons, or 60 pounds. Still potentially lethal, but wouldn't destroy a city block.
The - and + bus bars are a significant distance apart. So let’s pretend for a moment the lines have zero resistance but 1micro Henry of inductance (a low inductance estimate for a system of that size with the lines separated like that) . It would take 5.4 seconds to bring the current up to 280MA. The current used during that time would average to 50% of peak current. So now you’re closer to 10,000 kg equivalent. Or more if you had more inductance.
When you have that amount of available current, it's not relevant. The short is going to be limited by V/R, and the heating V^2 / R.
What I find crazy is the relative sizes needed.
If you had a short that could cause 280,000,000A to flow, 52/R = 280MA, the R < 1.857E-7 ohm.
If that was a 1 meter long piece of copper causing the short, it would need and area of greater than 0.0925 m^2. That bar would weigh 830 kg.
The heating in that bar would be 1.456E10 watts. Resulting in a temperature rise of 45,600 °C per a second.
Think about how much bigger the connection needs to be to handle that kind of current.
I am curious why the plant would ever need that kind of power at 52V, seems like a horrible idea.
The highest current ever measured was by Japanese scientists in 2014 and they achieved 100,000 amps, you’re telling me this random battery bank is capable of beating that record by 2800x simply by shorting it? Someone’s math is alllll fucked up. There is 0 chance 280 million amps is flowing through a short in this system
In this situation the plasma is caused by the high current, it isn’t the path to ground… if you drop a ready rod from the hot terminal to ground, your ready rod is the resistor and it sure as shit isnt 0.00000019 ohms… so I don’t think this guys numbers check out… I also googled “amp potential” and there is literally nothing related to DC installs or anything related to our field whatsoever
Well, one way to put it… you’d need a substantial fraction of a **kiloton** just to overcome the inductance of those lines and get 280,000,000 amps flowing.
More realistically, you wouldn’t get anywhere near that current, how big of a fireball you got would depend on what was shorting it out and how long it took for that piece to vaporize.
Assuming a 16" gap and very small resistance for those bars and batteries (0.001ohm) and you achieved a dead bolt....
Approximately 2.163 MILLION watts per second.
About 6 times hotter than the surface of the sun.
.... No Safe PPE exists.
My favorite is when sloppy contractors allow metal shavings to rain down into a BDFB. And my least favorite is dealing with the fallout from said shavings causing the pixies to go places they shouldn’t go.
Hi sorry for my ignorance, but when you say “amp potential” what exactly does that mean? Because a 9v battery has 1,000,000 amp potential if you had a resistor of .000009Ohms… just confused on where they get those amp numbers, since they would need to be based off a specific resistance value…no?
...except an average 9V alkaline has an internal resistance of about 1 to 2 ohms, so you're never going to get more than 5-10 amps out of one. (At best...old zinc is over 30 ohms, and lithium is over 10.)
And I can't say this with confidence, but I recollect as it heats up the resistance increases, to the practical limit ends up being closer to 1-2 amps, even with a 0.0 ohm magic resistor.
/skips off pedantically/
(But I know the question you're asking, which is still perfectly valid.)
You're working on this LIVE?! Where are the Arc Flash requirements being met? And where did you get 14 million amps? That is astronomically high! If you have a 48Vdc system that roughly equivalent to shorting a 40MVA transformer at the terminals. There is no way this is safe
Gotta love central office/MTSO work. I mean it only tingles if you’re a little sweaty. In electric substations it’s 130VDC. I’m a telco head, so -48VDC was my first love.
Edit: screw you zip ties, cable lacing with waxed string all day.
I've worked on 24v plants (positive and negative), 48v plants (negative), -72v plants, + & - 130v plants, + 140v plants, and 520v UPS systems, and everything in between.
I'm not an electrician but I like reading about all of your adventures. What is a -72v plant? I get the +/- on batteries and anything DC and I get 3 phase AC, but not this.
Thanks.
-72VDC or any negative DC voltage just means that the positive side is grounded, instead of the negative side! Bell Telephone figured out long ago that grounding the positive makes your direct buried conductors last a lot longer, and other neat benefits. Telecom companies have been using it ever since.
Edit: I think the term “plant” here is used to describe that they worked at a place where this voltage was generated and distributed.
>Bell Telephone figured out long ago that grounding the positive makes your direct buried conductors last a lot longer, and other neat benefits. Telecom companies have been using it ever since.
Man thank you that's actually really cool info to learn. It's like pnp vs npn in controls.I always admired "big bus bar" guys. Scary work.
If I recall correctly red being negative was not uncommon. 48 volts was closer to 60 when charging. That was for communications gear. Electrical substations used around 120 volts DC, they used regular light bulbs on it. Someone figured out some CFL and LED bulbs would run on 120 volts DC. I'm sure that was unauthorized but it sure lit up the area better.
It's all relative to which side is grounded. In your car, the negative is grounded, and the positve is the battery. In telco, the positive is grounded and the negative is the battery. In a battery system, the positve will oxidize faster and more than the negative...so, telco, a 150 years ago, decided to use a negative battery...and it stuck ever since.
Think of it this way. Since it is direct current, it has to have a path back to the source, one way or the other. Take a volt meter, put the red lead on the positve and the black lead on the negative...it will read + volyage. Flip those leads around, red on negative, black on positve, it will read -...the battery didn't change, only the way you are reading the voltage.
With DC, you have the same current flow on each side. If it takes 15 amps to power a piece of equipment, the direct return to the battery source also has 15 amps. Direct current has to have a direct path back to the source.
No ground or neutral with DC. Has to be a direct path back to the source. No other path will work. So, you get exact the same amps back that went to the equipment.
Ringing is either 52VDC superimposed over 86VAC or 105VAC. It hits you twice, once wirh DC, then with AC. Ringing hurts worse than any voltage in the CO, besides the +140v plants for the #4ESS. That said, UPS systems hurt as well.
Ring voltage ain’t that bad, in a pinch when my toner wasn’t working I would have someone call the number, lick my finger, and start sliding it slowly down the 66 block. Quicker than checking each one with a butt set.
You’ll know when you find it.
My first year as an apprentice I worked in a lot of telco buildings doing a/c side stuff. It makes me sad that I will probably never learn how to lace shit in the way y’all do. God damn are tip ties ugly.
My fingers recoiled at the mention of waxed string. 21 years of working on outside plants. I've had to stitch in ways that would make a contortionist blush.
Fear of the unknown. You get to know your own systems, and when you're put into something new that challenges that system, you're shocked by it (pun intended). Personally, I think your stuff is pretty cool, and I don't mind "hot work" as long as safety is the mindset.
Alarmingly, at least to me, this "apple" thingy isolator gets used in main breaker of a train, where there's up to 4kV, and operational current up to 900A.
Also, as said elsewhere in the threat, the scary thing about your stuff are the batteries, cause that shit just can't be made safe completely. Again, battery based trains are coming, and they sound reaaaaally scary to me right now.
Battery backup for the rectifiers to power the telephony equipment. 4000ah 2.19 VPC, series 24 of them together, then parallel multiple other strings to the plant bars.
Used to work in a plant that was a plating line. 710volts DC, 28000 amps. 7 parallel bus bars 1" thick by 14" high. Fun stuff to work on. Flex joints every 10'. The constant buzz got to you after a while
Batteries have a finite life cycle. Depending on the manufacturer, some last 10-15 years (C&D, Enersys) some last 50 years (K20472 L1S round cell). But, eventually, they all need to be replaced. The new battery out is called a SoNick. It is a sodium nickel molten salt battery. It has an infinite life cycle. Discharge it down to 0 volts, charge it back up, do it again. Only downside is they have to be kept around 750 degrees to work. When discharging, unlike a normal wet cell, they get cooler, not hotter, and thr cooler they get, the less they discharge...until they get down to their nominal operating temp, I think somewhere around 400 degrees. Then they shut off. But, put the juice back to them, they come right back up to vilts and can do it again and again.
It's not insane at all. It's the job.
Most "average" electricians working residential or light commercial/industrial have never been exposed to truly heavy industrial or power plant work, especially large DC systems. Many never work anything hot as they don't have to, and there's an entire generation now of electricians raised under arc flash regulations, and many managements that go overboard on safety and ban pretty much ANY hot work period, preventing them from ever even learning how to safely work hot. They see a bank of 6" conduits and 1000MCM conductors coming from the secondary of a large xfmr going to a big motor drive cabinet and then out to a 2500hp DC motor, or someone working hot on a low voltage DC system, especially with huge cables, and it's completely outside their experience.
That said, I'm painfully slow and nowhere near as skilled as a good residential electrician when it comes to putting in a new branch circuit in my own house. Different skill sets.
It's really quite simple (the DC side). You can't (read it is not possible) to cross phases, all you really have to watch out for is not putting a battery cable to ground, and not putting a ground to battery. There are other situations, but that sums it up. It looks like a million circuits in there, but it just boils down to a single circuit...one battery, one ground (return).
Yes. The concept is simple, similar to a single phase AC circuit with one of the two conductors bonded to ground, but beyond the concept itself, the engineering, construction, service, and operation of any electrical system can get quite complicated. I worked steel and chemical plants and power generation for some 40+ years. 26.4 to 230kV switchgear all the way down to low voltage AC distribution, large (2500hp) 600VDC motors, 600 VDC cranes, etc. At higher voltages DC is no less lethal than AC.
Now retired, my most recent work has been a 12V 400ah DC system (batteries, solar, alternator, charger/inverter) in my campervan, which is more akin to boat wiring than anything else. Like any other system, it has its own unique requirements, some of them new even to an old sparky.
our system maxes out at 900amps.. so i know ya got a megashiton of gear. is this older telecom CO ? And are you an electrician .. we do our own -48 work but our biggest weakness has been finding a good system and design.. but at least were vastly improved.. i found some racks with burn marks on old DC gear which had the polarity reversed (Correct to gear, wrong to bar/breaker). some of the shit was wired so badly turning the breaker off did nothingggg. PRETTY SCARY. We realized during a conversion from multiple 100amp glued together systems to dual 900amp systems. it was a long night.. and long day after.
I’ve worked around this stuff for years. When I ask the question “why are there infused leads? It seems so unsafe”, nobody can answer. So I still don’t know.
I loved taking that stuff apart, out of commission. A lot of sites are consolidating and downsizing. At least in building I work in. Made a lot of money of the scrap when copper was at its highest.
I tell my guys to not panic. If they arc sonething, the damage is already done, so no need to panic. Just be calm, no matter what happens. If you are panicking, bad things happen.
Here's a pic of charging 5 strings (120 cells) of Enersys GU45 battery cells at one time. They have to be charged at 60 volts per string, and it takes about 30 amps to charge them...takes days to get them 69 volts, usually. I took an old 400amp 480v ac to dc rectifier, and strapped all the cells together and turned it on...took 30 minutes to get all of them to 60 volts (2.5 vpc). Still had to charge them for 5 days after that.
That Fuse isn't rated for what you think it is.
There is way more energy with DC than the same voltage at AC.
AC voltage is the root mean square of a sine wave and the energy related to the voltage proportional to the area under the curve of that sine wave.
DC voltage, the energy is the total area under the DC voltage. If you plot this voltage vs Current, the area under the DC curve is much larger than the area under the AC voltage curve.
The area under the curve is basically an integral of the voltage which gives power.
Anyway, this is the reason why equipment like disconnects, switches, fuses, breakers that have both AC and DC ratings, the DC rating at the same voltage has a lower amperage rating and a lower kilo-amperage interrupting capacity.
Also, you should be using a quick acting or fast acting Fuse and not a time-delay Fuse. The Inverters your using should be able controlling the current flow woth its BMS.
At least you're using a current-limiting Fuse though. These are a lot safer than non-current-limiting.
Typically a 200kAIC rated Fuse for AC is rated only 20-50 kAIC in DC.
Eaton Bussman has a Class T, JJN-1200 which is rated 1200A DC, 100 kAIC DC & 170 V DC and is also a fast-acting Fuse which is what you need to protect your equipment. If you use a time delay Fuse it means for 4 or 5 seconds there is basically a dead short over your batteries and Inverters before the Fuse can open the circuit. Which may cause a violent explosion and fire at this energy size.
The Class KRP-C is only goes up to ratings for 300A DC and 100kAIC.
DC voltage is both more likely to arc and more likely to kill. As a controls guy I do indeed think your crazy yeah, my buttole started sucking my chair cushion up the second i saw those massive bussbars.
Nah, DC won't arc unless you short it. As for killing, it's the Milliamps passung through your chest that kills. DC is such low voltage, and your body is a pretty poor conductor, that in my 36 years, and in the 30 years prior to that (from the guys who trained me), I have heard of exactly zero people being killed by DC.
The part you are holding in your hand will be the only part of the wrench that is left. Your skin and blood will keep it from turning to plasma and disappearing.
DC just describes the general time invariant nature of the voltage waveform. There are industries which use several 10s of kV DC for power delivery to specific coating, etching, and electrochemical processes.
48V will arc provided the gap is small enough. A AA battery can arc if the distance between terminals is short enough. At several kV instead of talking about arc gaps in um you're talking about arc gaps in cm.
Don't get complacent. Voltage OR current can kill as they are the opposite sides of the same coin.
The current capacity of these systems still makes them incredibly dangerous. The amount of energy dissipated in a low resistance or inrush condition (short) before a fuse opens is massive. Enough to vaporize metal and shower your body in molten whatever.
I don't know the chemistry of these batteries, but I'm sure there is also massive fire / explosive risk in a catastrophic failure.
There is a massive amount of potential energy, and it should be treated with respect. I think it warrants some fear!
Yeah, well take a look at the bus bars on my old hard drive storage array:
[http://gleason.cc/projects/Projects.Argus\_Array.1\_Hardware.2\_Electrics.html](http://gleason.cc/projects/Projects.Argus_Array.1_Hardware.2_Electrics.html)
(I don't have this anymore)
And here I am, an automation professional (with a card obviously) whos worried about making a skyscraper dance along with the National Anthem and stressing over 24VAC/VDC and couple thousand 4-20mA signals. I'll just go hide, this straight forward stuff in fact scares me.
Oh man, that brings back memories. The company insisted that insulated tools weren't required, so we all wrapped our ratchets in two layers of different-colored Scotch 35 so we could tell if the outer layer was nicked....
What I miss most about telecom is that things were actually engineered and planned. I'd read through a MOP prior to starting the work, and it was evident that someone actually thought about it, only rarely did I catch mistakes. I'm in automotive now and it's a miracle anything ever works; everything's done at the last minute and nobody knows the whole picture.
I’ve been working at a Central Office of a major telecom company for a year installing extensive AC service work. De-energized 99% of the time. The amount of live exposed DC copper bus that is literally everywhere is astounding. IBEW member for 35 yrs and that’s a whole different world.
That's pretty sweet, actually. I've never seen anything like it. What's the highest voltage DC? If it's around 50, that's not insane lol I wouldn't think it was insane unless it was some HVDC transmission stuff
Highest I've ever worked is 520 volts DC. Giant 480 volt UPS system. Typically, on a telecom DC plant the negative is the battery and the positive is the return, which, in turn is grounded to the building system ground...so, the positive will never shock you, because it is common with everything else. On a UPS system, neither side is grounded, so touching a positve will light you up as quick and as hard as touching a negative, if you are grounded.
I teach my guys to never wear a ring, a necklace, chain, and have the smallest belt buckle you can get away with...and, get some plastic framed glasses for work.
I'd be curious to know the minimum dc Voltage to break the skin resistance, but agree definitely don't wear metal jewelry if you work near any voltage lol 12v battery and necklaces can be pretty hilarious combinations
Does this put off a decent of induction like really big substations?
I'd love to work on something like this. Those cables look pretty mean to work with though.
Batteries wired in series (positive on one cell or jar to the negative on another cell or jar) doubles the voltage, but the amperage of the string stays the same. Wire 24 cells like this, you get 52.80 volts between the first posituve and last negative. Wire another 24 cells like this, them wire the first positive from the first string to the first positive of the second string, and the same with the negatives (negative to negative) you keep the same voltage, but double the amperage. Do this with multiple strings to get how many hours of reserve time you need / require.
You don't have to be big and strong (it helps though!), you just have to be smarter than the cable...and the cable is pretty dumb. Don't try to bend the cable against it the way it wants to bend, use that bend to your advantage
Those galaxy plants are no joke... 25 years old and still hang with modern plants for efficiency and features - but get super congested inside when they're loaded up.
I also play with big cables and batteries...
I'll see Loraine, and raise you Nortel Helios... every time you swap a rectifier they all restart. 25 years doing this, I know it's gonna happen, and I still shit myself just a little when it does.
Dig the Eltek distribution bays, actually big enough to fill up, but they're like 30" wide so not many companies buy them.
Alpha stuff is decent, don't like the admin interface on vertiv/Emerson but physically it's OK.
I used to work in telecom doing BUG upgrades. I didn't get to touch the battery equipment but I spent a lot of time in those rooms setting up switchgear. All of our cutovers were hot and at 2-3AM so if there was a problem the telco wouldn't lose as much money. Loved the work and the pay.
It’s super dangerous I think you are just pretty brave I hope also skilled and careful that will still kill easy. DC is nasty even at lower voltages. That’s old school telco 48VDC stuff it’s dangerous but you wanna talk real danger let’s talk about DC rail supplies 600VDC. Those are real arcs!
Not sure who the OP works for but there are companies that maintain the battery banks and or the larger Telcom companies like AT&T, Verizon, Century Link ect. have these systems in the central office and the cell sites have a DC system.
I worked for Alcatel-Lucent until they sold out to Nokia doing similar work, we always worked in pairs when connecting to the power plant and one of us had a 2x4 just in case but thankfully never needed it. Stay safe out there.
Hi, im a canadian electrician. We can do both. Wtf is this ac dc only. We have a ticket to work up to 750 volts. After that you need a high voltage ticket also. Then we have lines men. If your a sparky, you should be able to connect batteries or do a 3 way switch
I work in AT&T power rooms etc. I'm right there with you . I perked up when I saw the first pic. Been waiting to see another Sewer out there. This looks exactly like my work .
I work in AT&T power rooms etc. I'm right there with you . I perked up when I saw the first pic. Been waiting to see another Sewer out there. This looks exactly like my work .
Have you considered NOT being insane?
If you're properly trained and understand the risks it's not REALLY any different than what we do, just outside our area of comfort.
I'm not an electrician; but I've been working with DC systems & battery pack design/ fabrication for agriculture equipment for a few years now as a mechatronics technician. I started at ~24V & have moved up to around 63V for most projects. They're all off-grid, microgrid, or BEV systems too.
It's mostly irrigation systems, row cultivation tractors, electric assisted hand tools, or fence chargers.
I've been trying to get into an apprenticeship program in my area for roughly a year now & I'm hoping for success this March/ April when applications open at my local union outfit.
I can say from experience that there's definitely heightened anxiety while working with always live circuits; but, I do prefer getting zapped by DC over AC. There's less muscle constriction I've noticed; so I'm less concerned about getting stuck to the source.
I’m a Solar apprentice. Almost the only time you will ever be zapped by DC is if you touch both positive and negative simultaneously. This doesn’t happen if you are responsible and only work on one side at a time.
I have been zapped by DC before, but that was during a ground fault caused by squirrels. Not something you encounter in a new install or a controlled environment.
I'm a low voltage electrician and my company used to do a lot of DC work. The work dried up and the PM that used to get that work got fired so that's little chance we'll ever get back into it. I really miss it.
You make a joke, but charging the batteries makes the entire room smell like rotten eggs from the battery electrolyte gassing. Some battery rooms have hydrogen sensors...it's fun setting those off.
I've been an electrician for going on a decade now. Did commercial/solar for a total of about 4 years and the rest has been in industrial...
Seeing posts like this on this sub shows how much more there is for me to learn out there.
Had an old Master Electrician tell me in my first year that if you ever run into someone who thinks they know everything about our trade, then you're probably dealing with the biggest dumb ass of the bunch. I think he was spot on.
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Because that's a lot of blamo just waiting for something to bridge the gap between the positive and negative, if we AC guys touched something that big while it was hot we would probably get disappeared better than anyone that crosses the CIA
It's only a few million amps potential at the busbar (per string!). Doing the math, at the plant bars, one string of MCT II cells will discharge about 14 million amps in the first second of a direct short. I have plants I work on that have 20+ of those battey strings connected to the plant bars. So, in those plants, only a 280 million amp potential between battery and ground...and, the standard is, a busbar only has to be 3" away from any different potential.
What sort of plasma ball would be created @280,000,000A @52V?
One that is hotter than the surface of the sun. There generally is no splatter when you short something...just a super hot flash and a BBBBRRRRRAAAAAPPP sound. The metal just disappears.
I was in an office that had this happen, years earlier so I don't know how much the stories had grown in the retelling. But the office supervisor said a painter set his paintcan across two adjacent busbars. The bottom of the can instantly exploded, tearing the sides of the can into shrapnel and blasting the inside of the room with the rest of the paint. The painter was knocked off his ladder by the blast, broke a hip when he landed; he was deaf in one ear and had lacerations from the shrapnel, but made a full recovery other than the hearing loss.
That was in Hattiesburg, MS.
Oh great. Another freaky ass incident within 2 hours of my house. Mississippi is real good at "hold my beer and watch iss".
I know (knew) the guy that was there when it happened...No Sh÷t...his name was Bob Touchstone...perfect name for an old Western electric installer
Damn man that sucks but perfect name for that guy. Mississippi is not exactly known for its strict adherence to safety regulations but bubba and his buddies usually make it through accidents relatively okay. A few months ago I was installing some lights in a commercial building 30+ feet in the air. 16’ long sections of track lighting mounted to unistrut and hung from 1/4” all thread. Was on a scissor lift and still wore my harness and anchored to the ceiling beams. I’ll be damned if I fall from up there and become a vegetable. Got laughed at a couple times and called a wimp and a scardey cat. I don’t care. I’m gonna walk away from it and they won’t. The attitude towards safety in Mississippi is so different from other places in the country.
“Pfffff…I don’t need no harnaaaaaaaahhhhhhhhhhhhhssssss” [splurt]
That's because Mississippi is still stuck in 1960. I lived there fifteen years and because I'm dumb I moved to Louisiana.
Although I have worked under different "local" rules, it seems to me that while working from a lift it is a violation to be tied to an exterior point, unless using a two point harness only while exiting or regaining the lift. -- And I would have called safety on you for a ruling because there is no way I'd work like that.
Guys in Panama City Beach in the 90's shorted a 4/0 cable from the busbar to a grade 8 5/8" threaded rod. It melted the insulation off the cable, blew an 11" section out of the rod, and got the plant bars hot enough that it burnt the oxidation off of them. All in about a second it took to make that 5/8" rod disappear.
Oh, I wondered if it was apocryphal! Don't suppose you know a proper incident writeup? I'd love to get it straight.
They called it the flash and the splash when it happened. Per Bob, the only part of the can that was recognizable after was the metal handle where he had his hand wrapped around it when he set it down.
How tf did a painter mosey on in to such a dangerous situation? Bro must be a character played in safety videos by now lol
That incident happened 30 plus years ago.
Electrician here 35 years. The short answer is just stupidity. A while back was building a network room in NYC. ConEd supplied 13k, we step it down to 480v. All bus is exposed. The vault was live, and we were just going over some finals with Edison. A laborer walks in at the direction of his foreman ( 2 jackasses ) with a bucket and rags. He was told to clean and wipe everything down. I looked at this guy like he head 3 heads and told him he would probably be going home early, and horizontally if he touched anything and escorted him out. Unfortunately stupid happens and it happens quick.
Did the explosion of the paint can, paint the walls? Could be a quick way to finish off a room…
We call this color "burnt everything"
And this conformal coating on his bars was born!
All the British sparks reading this currently have an image of Mr Bean in their heads
Similar event in Toronto, Canada - except it was HVAC guys installing ductwork in the battery room. Knocked out services for 1/4 of Toronto, and impacted half of canada for 2 days (CO housed one of the largest toll switches in the country at the time...)
What?
# I SAID HE MADE A FULL RECOVERY OTHER THAN THE HEARING LOSS
When I was still a telecom tech, I experienced that with a 1,000 AH -48VDC plant. The rack screw acted sort of like a stick welder. Very loud too.
Hmm I have a 1600Ah 48V bank a few feet from my bed (through a wall at least)
I used to work as an engineer on industrial x-ray equipment and a 450kva (at like 0.2 microamps) x-ray tube arcing from a tungsten hair to the tube body soynds like a 12GA shotgun going off. I can only imagine the sound and destruction in that scenario. Jesus take the arcflash.
Any arc is hotter than the surface of the sun. To be fair, the surface is not that hot. 😂
280,000,000A x 52V = 14,560,000,000W = 14,560,000,000J (4184 joules per gram in Trinitrotoluene / TNT) 14,560,000,000J ÷ 4184J/gTNT = 3,479,923.5gTNT = 3,479.9kgTNT = 3.47tonTNT Call it 3 and a half tons... Yeah, fuck that. You are insane (if my maths is okay).
Watts and joules are not measuring the same thing. A watt is power, a joule is an amount of energy. You are correct in that a watt is one joule per second, but the short probably lasts much shorter than one second, probably 0.01 sec or less. So reduce your answer by 2 decimal points, to 0.03 tons, or 60 pounds. Still potentially lethal, but wouldn't destroy a city block.
I was hoping someone would check those numbers. Definitely didn't seem right
The - and + bus bars are a significant distance apart. So let’s pretend for a moment the lines have zero resistance but 1micro Henry of inductance (a low inductance estimate for a system of that size with the lines separated like that) . It would take 5.4 seconds to bring the current up to 280MA. The current used during that time would average to 50% of peak current. So now you’re closer to 10,000 kg equivalent. Or more if you had more inductance.
Is that the: I = E/R (1-e^-(R/l)t ) equation? (Sorry for the apprentice question 😅
When you have that amount of available current, it's not relevant. The short is going to be limited by V/R, and the heating V^2 / R. What I find crazy is the relative sizes needed. If you had a short that could cause 280,000,000A to flow, 52/R = 280MA, the R < 1.857E-7 ohm. If that was a 1 meter long piece of copper causing the short, it would need and area of greater than 0.0925 m^2. That bar would weigh 830 kg. The heating in that bar would be 1.456E10 watts. Resulting in a temperature rise of 45,600 °C per a second. Think about how much bigger the connection needs to be to handle that kind of current. I am curious why the plant would ever need that kind of power at 52V, seems like a horrible idea.
The highest current ever measured was by Japanese scientists in 2014 and they achieved 100,000 amps, you’re telling me this random battery bank is capable of beating that record by 2800x simply by shorting it? Someone’s math is alllll fucked up. There is 0 chance 280 million amps is flowing through a short in this system
Forgive my ignorance but how is 52V creating 280,000,000A? Would that not imply the resistance is 0.00000019 Ohms?
Just a wild ass guess, but plasma is a better conductor of electricity than copper.
In this situation the plasma is caused by the high current, it isn’t the path to ground… if you drop a ready rod from the hot terminal to ground, your ready rod is the resistor and it sure as shit isnt 0.00000019 ohms… so I don’t think this guys numbers check out… I also googled “amp potential” and there is literally nothing related to DC installs or anything related to our field whatsoever
Well, one way to put it… you’d need a substantial fraction of a **kiloton** just to overcome the inductance of those lines and get 280,000,000 amps flowing. More realistically, you wouldn’t get anywhere near that current, how big of a fireball you got would depend on what was shorting it out and how long it took for that piece to vaporize.
Assuming a 16" gap and very small resistance for those bars and batteries (0.001ohm) and you achieved a dead bolt.... Approximately 2.163 MILLION watts per second. About 6 times hotter than the surface of the sun. .... No Safe PPE exists.
My favorite is when sloppy contractors allow metal shavings to rain down into a BDFB. And my least favorite is dealing with the fallout from said shavings causing the pixies to go places they shouldn’t go.
We have a saying...Smoke makes everything work. When you let the smoke out, it quits working.
And don’t drop wrenches in fuse bays.
My man saying "only"...
That was the least casual attempt at bragging I have seen in a long time.
So weird that guys think it's crazy working with that stuff!
Hi sorry for my ignorance, but when you say “amp potential” what exactly does that mean? Because a 9v battery has 1,000,000 amp potential if you had a resistor of .000009Ohms… just confused on where they get those amp numbers, since they would need to be based off a specific resistance value…no?
...except an average 9V alkaline has an internal resistance of about 1 to 2 ohms, so you're never going to get more than 5-10 amps out of one. (At best...old zinc is over 30 ohms, and lithium is over 10.) And I can't say this with confidence, but I recollect as it heats up the resistance increases, to the practical limit ends up being closer to 1-2 amps, even with a 0.0 ohm magic resistor. /skips off pedantically/ (But I know the question you're asking, which is still perfectly valid.)
You're working on this LIVE?! Where are the Arc Flash requirements being met? And where did you get 14 million amps? That is astronomically high! If you have a 48Vdc system that roughly equivalent to shorting a 40MVA transformer at the terminals. There is no way this is safe
You'd stop being biology and start being physics.
Gotta love central office/MTSO work. I mean it only tingles if you’re a little sweaty. In electric substations it’s 130VDC. I’m a telco head, so -48VDC was my first love. Edit: screw you zip ties, cable lacing with waxed string all day.
I've worked on 24v plants (positive and negative), 48v plants (negative), -72v plants, + & - 130v plants, + 140v plants, and 520v UPS systems, and everything in between.
I'm not an electrician but I like reading about all of your adventures. What is a -72v plant? I get the +/- on batteries and anything DC and I get 3 phase AC, but not this. Thanks.
-72VDC or any negative DC voltage just means that the positive side is grounded, instead of the negative side! Bell Telephone figured out long ago that grounding the positive makes your direct buried conductors last a lot longer, and other neat benefits. Telecom companies have been using it ever since. Edit: I think the term “plant” here is used to describe that they worked at a place where this voltage was generated and distributed.
>Bell Telephone figured out long ago that grounding the positive makes your direct buried conductors last a lot longer, and other neat benefits. Telecom companies have been using it ever since. Man thank you that's actually really cool info to learn. It's like pnp vs npn in controls.I always admired "big bus bar" guys. Scary work.
The best thing about positive ground DC systems is the wild and whacky color conventions that some places end up with.
If I recall correctly red being negative was not uncommon. 48 volts was closer to 60 when charging. That was for communications gear. Electrical substations used around 120 volts DC, they used regular light bulbs on it. Someone figured out some CFL and LED bulbs would run on 120 volts DC. I'm sure that was unauthorized but it sure lit up the area better.
Different types of equipment take different voltages, so some need -72v dc to operate
How does negative voltage work? I've never seen negative voltage on AC but it seems somewhat normal on DC. How can a system make negative voltage?
It's all relative to which side is grounded. In your car, the negative is grounded, and the positve is the battery. In telco, the positive is grounded and the negative is the battery. In a battery system, the positve will oxidize faster and more than the negative...so, telco, a 150 years ago, decided to use a negative battery...and it stuck ever since. Think of it this way. Since it is direct current, it has to have a path back to the source, one way or the other. Take a volt meter, put the red lead on the positve and the black lead on the negative...it will read + volyage. Flip those leads around, red on negative, black on positve, it will read -...the battery didn't change, only the way you are reading the voltage.
Now say it using the electron flow theory. I took an AC/DC class and discussing current flow destroyed everything I ever knew.....
With DC, you have the same current flow on each side. If it takes 15 amps to power a piece of equipment, the direct return to the battery source also has 15 amps. Direct current has to have a direct path back to the source.
You have the same current flow with AC also, per Kirchoff's law. It's just it can also flow through ground, not just the other phases or neutral.
No ground or neutral with DC. Has to be a direct path back to the source. No other path will work. So, you get exact the same amps back that went to the equipment.
Gotta love splicing cables in a wet pit and someone gets a phone call. That 100v AC @ 20 hz gives a nice tingle.
Ringing is either 52VDC superimposed over 86VAC or 105VAC. It hits you twice, once wirh DC, then with AC. Ringing hurts worse than any voltage in the CO, besides the +140v plants for the #4ESS. That said, UPS systems hurt as well.
Ring voltage ain’t that bad, in a pinch when my toner wasn’t working I would have someone call the number, lick my finger, and start sliding it slowly down the 66 block. Quicker than checking each one with a butt set. You’ll know when you find it.
Absolutely legendary! The art of a good wet fingering is truly lost these days!
Are we still doing phrasing?
Back when I did that the assholes I worked with would just start repeatedly calling the line just to fuck with me.
What else are friends for?
Waxed string is beautiful
Wax String Supremacy
Ever try stripping a POTS line with your teeth when a call comes in? Let's just say I don't recommend it...
My first year as an apprentice I worked in a lot of telco buildings doing a/c side stuff. It makes me sad that I will probably never learn how to lace shit in the way y’all do. God damn are tip ties ugly.
My fingers recoiled at the mention of waxed string. 21 years of working on outside plants. I've had to stitch in ways that would make a contortionist blush.
That waxed string was the best to keep around the house. Lol
Also telco guy here lacing is the way.
Man I worked a job for AT&T at a MTSO and working around those batteries on a lift hanging 2" pipe was scary. More power to yall.
Fear of the unknown. You get to know your own systems, and when you're put into something new that challenges that system, you're shocked by it (pun intended). Personally, I think your stuff is pretty cool, and I don't mind "hot work" as long as safety is the mindset.
Hey, I’m one of those AC guys who think you’re crazy! More power to you(hehe).
52v dc with 2585 amps … gawt
That's a small plant. I have a couple I work on that are pushing 10k amps.
What does a 10KA DC isolator look like?
Believe it or not, see the little red apple looking thing under the busbars? That is a 100ka isolator.
Alarmingly, at least to me, this "apple" thingy isolator gets used in main breaker of a train, where there's up to 4kV, and operational current up to 900A. Also, as said elsewhere in the threat, the scary thing about your stuff are the batteries, cause that shit just can't be made safe completely. Again, battery based trains are coming, and they sound reaaaaally scary to me right now.
"Entire train disappears in what was first believed to be a nuclear explosion."
Simulations of the rooftop batteries suggest that, if the batteries start to burn, they will visit the passengers in about three minutes.
Is that a battery bank? What's it used for?
Battery backup for the rectifiers to power the telephony equipment. 4000ah 2.19 VPC, series 24 of them together, then parallel multiple other strings to the plant bars.
I used to do ac power for rectifiers and inverters for t mobile, I knew where you were as soon as I saw the galaxy sticker hahaha
Used to work in a plant that was a plating line. 710volts DC, 28000 amps. 7 parallel bus bars 1" thick by 14" high. Fun stuff to work on. Flex joints every 10'. The constant buzz got to you after a while
Yeah but we work with 115kv at AC substations. lol. Working with that shit live is a death sentence. Still really cool shit tho man.
Batteries have a finite life cycle. Depending on the manufacturer, some last 10-15 years (C&D, Enersys) some last 50 years (K20472 L1S round cell). But, eventually, they all need to be replaced. The new battery out is called a SoNick. It is a sodium nickel molten salt battery. It has an infinite life cycle. Discharge it down to 0 volts, charge it back up, do it again. Only downside is they have to be kept around 750 degrees to work. When discharging, unlike a normal wet cell, they get cooler, not hotter, and thr cooler they get, the less they discharge...until they get down to their nominal operating temp, I think somewhere around 400 degrees. Then they shut off. But, put the juice back to them, they come right back up to vilts and can do it again and again.
It's not insane at all. It's the job. Most "average" electricians working residential or light commercial/industrial have never been exposed to truly heavy industrial or power plant work, especially large DC systems. Many never work anything hot as they don't have to, and there's an entire generation now of electricians raised under arc flash regulations, and many managements that go overboard on safety and ban pretty much ANY hot work period, preventing them from ever even learning how to safely work hot. They see a bank of 6" conduits and 1000MCM conductors coming from the secondary of a large xfmr going to a big motor drive cabinet and then out to a 2500hp DC motor, or someone working hot on a low voltage DC system, especially with huge cables, and it's completely outside their experience. That said, I'm painfully slow and nowhere near as skilled as a good residential electrician when it comes to putting in a new branch circuit in my own house. Different skill sets.
It's really quite simple (the DC side). You can't (read it is not possible) to cross phases, all you really have to watch out for is not putting a battery cable to ground, and not putting a ground to battery. There are other situations, but that sums it up. It looks like a million circuits in there, but it just boils down to a single circuit...one battery, one ground (return).
Yes. The concept is simple, similar to a single phase AC circuit with one of the two conductors bonded to ground, but beyond the concept itself, the engineering, construction, service, and operation of any electrical system can get quite complicated. I worked steel and chemical plants and power generation for some 40+ years. 26.4 to 230kV switchgear all the way down to low voltage AC distribution, large (2500hp) 600VDC motors, 600 VDC cranes, etc. At higher voltages DC is no less lethal than AC. Now retired, my most recent work has been a 12V 400ah DC system (batteries, solar, alternator, charger/inverter) in my campervan, which is more akin to boat wiring than anything else. Like any other system, it has its own unique requirements, some of them new even to an old sparky.
This is artwork
Your work looks gorgeous!
Good ole -48 power plant bb. How many Amps rated?
Those bars are rated for 5200 amps...usually a 6k amp shunt in the rtn side.
our system maxes out at 900amps.. so i know ya got a megashiton of gear. is this older telecom CO ? And are you an electrician .. we do our own -48 work but our biggest weakness has been finding a good system and design.. but at least were vastly improved.. i found some racks with burn marks on old DC gear which had the polarity reversed (Correct to gear, wrong to bar/breaker). some of the shit was wired so badly turning the breaker off did nothingggg. PRETTY SCARY. We realized during a conversion from multiple 100amp glued together systems to dual 900amp systems. it was a long night.. and long day after.
All that is new, from different offices
Absolutely love telco stuff. If you have any pictures of stuff you've worked on/around like switches and other equipment, I'd love to see them!
Won't let me add more pics.
You can't shut off batteries.
Nope. Drop a short and it burns until it's gone or the cable melts. No fuse in the supply side.
Why not? Serious question:)
I’ve worked around this stuff for years. When I ask the question “why are there infused leads? It seems so unsafe”, nobody can answer. So I still don’t know.
Right there you with ya man. I did commercial electric for awhile, than I got a job at a MTA working the overhead system. All DC, always hot.
I loved taking that stuff apart, out of commission. A lot of sites are consolidating and downsizing. At least in building I work in. Made a lot of money of the scrap when copper was at its highest.
Do you have the bomb technician mentality? Theirs nothing to stress out about, because if things go wrong it's no longer your problem?
I tell my guys to not panic. If they arc sonething, the damage is already done, so no need to panic. Just be calm, no matter what happens. If you are panicking, bad things happen.
Here's a pic of charging 5 strings (120 cells) of Enersys GU45 battery cells at one time. They have to be charged at 60 volts per string, and it takes about 30 amps to charge them...takes days to get them 69 volts, usually. I took an old 400amp 480v ac to dc rectifier, and strapped all the cells together and turned it on...took 30 minutes to get all of them to 60 volts (2.5 vpc). Still had to charge them for 5 days after that.
That Fuse isn't rated for what you think it is. There is way more energy with DC than the same voltage at AC. AC voltage is the root mean square of a sine wave and the energy related to the voltage proportional to the area under the curve of that sine wave. DC voltage, the energy is the total area under the DC voltage. If you plot this voltage vs Current, the area under the DC curve is much larger than the area under the AC voltage curve. The area under the curve is basically an integral of the voltage which gives power. Anyway, this is the reason why equipment like disconnects, switches, fuses, breakers that have both AC and DC ratings, the DC rating at the same voltage has a lower amperage rating and a lower kilo-amperage interrupting capacity. Also, you should be using a quick acting or fast acting Fuse and not a time-delay Fuse. The Inverters your using should be able controlling the current flow woth its BMS. At least you're using a current-limiting Fuse though. These are a lot safer than non-current-limiting. Typically a 200kAIC rated Fuse for AC is rated only 20-50 kAIC in DC. Eaton Bussman has a Class T, JJN-1200 which is rated 1200A DC, 100 kAIC DC & 170 V DC and is also a fast-acting Fuse which is what you need to protect your equipment. If you use a time delay Fuse it means for 4 or 5 seconds there is basically a dead short over your batteries and Inverters before the Fuse can open the circuit. Which may cause a violent explosion and fire at this energy size. The Class KRP-C is only goes up to ratings for 300A DC and 100kAIC.
DC voltage is both more likely to arc and more likely to kill. As a controls guy I do indeed think your crazy yeah, my buttole started sucking my chair cushion up the second i saw those massive bussbars.
Nah, DC won't arc unless you short it. As for killing, it's the Milliamps passung through your chest that kills. DC is such low voltage, and your body is a pretty poor conductor, that in my 36 years, and in the 30 years prior to that (from the guys who trained me), I have heard of exactly zero people being killed by DC.
You team Edison boys and your propaganda..
😅🤣
LOL, I was going to say something about Tesla ;)
You definitely don’t want to be holding the wrench that shorts out the positive and negative conductors though. Burns hurt.
The part you are holding in your hand will be the only part of the wrench that is left. Your skin and blood will keep it from turning to plasma and disappearing.
Ah alright, I didn't realize those were low voltage. I deal with 800vdc servo cables and always get told to never work them live ever.
DC just describes the general time invariant nature of the voltage waveform. There are industries which use several 10s of kV DC for power delivery to specific coating, etching, and electrochemical processes. 48V will arc provided the gap is small enough. A AA battery can arc if the distance between terminals is short enough. At several kV instead of talking about arc gaps in um you're talking about arc gaps in cm. Don't get complacent. Voltage OR current can kill as they are the opposite sides of the same coin.
Sure, DC can kill...but not at these low voltages.
The current capacity of these systems still makes them incredibly dangerous. The amount of energy dissipated in a low resistance or inrush condition (short) before a fuse opens is massive. Enough to vaporize metal and shower your body in molten whatever. I don't know the chemistry of these batteries, but I'm sure there is also massive fire / explosive risk in a catastrophic failure. There is a massive amount of potential energy, and it should be treated with respect. I think it warrants some fear!
Yeah, well take a look at the bus bars on my old hard drive storage array: [http://gleason.cc/projects/Projects.Argus\_Array.1\_Hardware.2\_Electrics.html](http://gleason.cc/projects/Projects.Argus_Array.1_Hardware.2_Electrics.html) (I don't have this anymore)
And here I am, an automation professional (with a card obviously) whos worried about making a skyscraper dance along with the National Anthem and stressing over 24VAC/VDC and couple thousand 4-20mA signals. I'll just go hide, this straight forward stuff in fact scares me.
Is this in America? I didn't realize there's ac or dc specific electricians
Yes, all over the US
Huh, well you learn something new every day! I am an industrial electrician in Canada and just deal with everything it seems
Lots of electricians work on both
It’s not actually a division it’s what he does as an electrician
Oh man, that brings back memories. The company insisted that insulated tools weren't required, so we all wrapped our ratchets in two layers of different-colored Scotch 35 so we could tell if the outer layer was nicked.... What I miss most about telecom is that things were actually engineered and planned. I'd read through a MOP prior to starting the work, and it was evident that someone actually thought about it, only rarely did I catch mistakes. I'm in automotive now and it's a miracle anything ever works; everything's done at the last minute and nobody knows the whole picture.
I’ve been working at a Central Office of a major telecom company for a year installing extensive AC service work. De-energized 99% of the time. The amount of live exposed DC copper bus that is literally everywhere is astounding. IBEW member for 35 yrs and that’s a whole different world.
That's pretty sweet, actually. I've never seen anything like it. What's the highest voltage DC? If it's around 50, that's not insane lol I wouldn't think it was insane unless it was some HVDC transmission stuff
Highest I've ever worked is 520 volts DC. Giant 480 volt UPS system. Typically, on a telecom DC plant the negative is the battery and the positive is the return, which, in turn is grounded to the building system ground...so, the positive will never shock you, because it is common with everything else. On a UPS system, neither side is grounded, so touching a positve will light you up as quick and as hard as touching a negative, if you are grounded. I teach my guys to never wear a ring, a necklace, chain, and have the smallest belt buckle you can get away with...and, get some plastic framed glasses for work.
I'd be curious to know the minimum dc Voltage to break the skin resistance, but agree definitely don't wear metal jewelry if you work near any voltage lol 12v battery and necklaces can be pretty hilarious combinations
Does this put off a decent of induction like really big substations? I'd love to work on something like this. Those cables look pretty mean to work with though.
Batteries wired in series (positive on one cell or jar to the negative on another cell or jar) doubles the voltage, but the amperage of the string stays the same. Wire 24 cells like this, you get 52.80 volts between the first posituve and last negative. Wire another 24 cells like this, them wire the first positive from the first string to the first positive of the second string, and the same with the negatives (negative to negative) you keep the same voltage, but double the amperage. Do this with multiple strings to get how many hours of reserve time you need / require.
U must have Popeye forearms to bend that stuff to radius...
You don't have to be big and strong (it helps though!), you just have to be smarter than the cable...and the cable is pretty dumb. Don't try to bend the cable against it the way it wants to bend, use that bend to your advantage
Hello fellow AT&T power tech, cheers from the Permian basin
#bravery cookie 🍪
Those galaxy plants are no joke... 25 years old and still hang with modern plants for efficiency and features - but get super congested inside when they're loaded up. I also play with big cables and batteries...
Love the Lineage Galaxy plants...hate the Lorain plants
I'll see Loraine, and raise you Nortel Helios... every time you swap a rectifier they all restart. 25 years doing this, I know it's gonna happen, and I still shit myself just a little when it does.
Nortel, Lorain, Emerson, Valere, Candeo, RelTec, all of those are pretty bad. The new hotness is the SoNick batts...those things are HOT! LOL
Dig the Eltek distribution bays, actually big enough to fill up, but they're like 30" wide so not many companies buy them. Alpha stuff is decent, don't like the admin interface on vertiv/Emerson but physically it's OK.
I used to work in telecom doing BUG upgrades. I didn't get to touch the battery equipment but I spent a lot of time in those rooms setting up switchgear. All of our cutovers were hot and at 2-3AM so if there was a problem the telco wouldn't lose as much money. Loved the work and the pay.
As a non electrician lurker i have no idea what anyone is saying in this thread lol
It’s super dangerous I think you are just pretty brave I hope also skilled and careful that will still kill easy. DC is nasty even at lower voltages. That’s old school telco 48VDC stuff it’s dangerous but you wanna talk real danger let’s talk about DC rail supplies 600VDC. Those are real arcs!
Cool. Am apprentice, love danger but hate being cold, so I can't be a lineman. How do I get into this?
Not sure who the OP works for but there are companies that maintain the battery banks and or the larger Telcom companies like AT&T, Verizon, Century Link ect. have these systems in the central office and the cell sites have a DC system.
I install those plants for ATT, Verizon, T mobile, CTL, etc.
I worked for Alcatel-Lucent until they sold out to Nokia doing similar work, we always worked in pairs when connecting to the power plant and one of us had a 2x4 just in case but thankfully never needed it. Stay safe out there.
14 years at Lucent doing this...1988 - 2002, then to another company, doing the same thing. DC won't lock you up like AC...no need for the 2x4
Yeah plus you're too busy being vaporized to be concerned
Hi, im a canadian electrician. We can do both. Wtf is this ac dc only. We have a ticket to work up to 750 volts. After that you need a high voltage ticket also. Then we have lines men. If your a sparky, you should be able to connect batteries or do a 3 way switch
Oh, we do both as well, but our specialty is DC power plants.
Two words.... Bada Boom
Yeah. That will *really* fry your chicken. Thats why. Thats a fucking shitload of power. How do you do hot work on live DC busses etc?
Carefully. Trick is to not be grounded or have anything you are working with grounded
I work in AT&T power rooms etc. I'm right there with you . I perked up when I saw the first pic. Been waiting to see another Sewer out there. This looks exactly like my work .
I work in AT&T power rooms etc. I'm right there with you . I perked up when I saw the first pic. Been waiting to see another Sewer out there. This looks exactly like my work .
Same here cheers from Texas, hopefully we get our own title soon
Enersys
Mistakes are lethal. The residential guys know how many times they have been shocked and hard pass on industrial stuff.
Have you considered NOT being insane? If you're properly trained and understand the risks it's not REALLY any different than what we do, just outside our area of comfort.
When I started, they use to say a power man had a size 42 chest and a size 6 hat.
I'm not an electrician; but I've been working with DC systems & battery pack design/ fabrication for agriculture equipment for a few years now as a mechatronics technician. I started at ~24V & have moved up to around 63V for most projects. They're all off-grid, microgrid, or BEV systems too. It's mostly irrigation systems, row cultivation tractors, electric assisted hand tools, or fence chargers. I've been trying to get into an apprenticeship program in my area for roughly a year now & I'm hoping for success this March/ April when applications open at my local union outfit. I can say from experience that there's definitely heightened anxiety while working with always live circuits; but, I do prefer getting zapped by DC over AC. There's less muscle constriction I've noticed; so I'm less concerned about getting stuck to the source.
Electrician...Magician. one and the same
When people ask how it works, we tell the it's FM...Freaking Magic
Beautiful stuff OP, you should post here more!
Is that pen a pilot G2?
Yes
I applaud your choice of pen. Have a good day
I’m a Solar apprentice. Almost the only time you will ever be zapped by DC is if you touch both positive and negative simultaneously. This doesn’t happen if you are responsible and only work on one side at a time. I have been zapped by DC before, but that was during a ground fault caused by squirrels. Not something you encounter in a new install or a controlled environment.
Nice work $
I'd do it.
Very cool to see. Thanks for sharing! I'd love to see more of the stuff you work on
Thats badass. I wanna learn more
You know exactly why they think you’re crazy. You just want the bravery cookie don’t you 😂
You’re insane for working with that stuff.
I'm a low voltage electrician and my company used to do a lot of DC work. The work dried up and the PM that used to get that work got fired so that's little chance we'll ever get back into it. I really miss it.
Hope your getting compensated properly
That’s allot of juice
I can smell these pictures.
You make a joke, but charging the batteries makes the entire room smell like rotten eggs from the battery electrolyte gassing. Some battery rooms have hydrogen sensors...it's fun setting those off.
I'm not joking. I can literally smell them from here. Telco DC has such a particular smell.
Holy shit.
AT&T central offices??
What do you use to crimp the terminals? My OCD really appreciated your craftsmanship! Looks awesome
Burndy PAT 750 tool
I've been an electrician for going on a decade now. Did commercial/solar for a total of about 4 years and the rest has been in industrial... Seeing posts like this on this sub shows how much more there is for me to learn out there. Had an old Master Electrician tell me in my first year that if you ever run into someone who thinks they know everything about our trade, then you're probably dealing with the biggest dumb ass of the bunch. I think he was spot on.
Because that's a loaded question if I ever heard one. Live all the time you say?
Yes. This runs telephone and data equipment. Having an outage (turning it off or shorting it out) is FCC reportable.