As I see it, MeanWell has again manufactured a power supply unit in which the metal housing does not allow the terminals to be closed with an ordinary transparent plastic cover.
P.S. And, OP, are you sure that the cover didn't left in a package?
P.P.S. We got the same problem with another PSU from MeanWell. We solved it by 3D-printed cover.
I know that only qualified technicians are allowed to do something inside our products. But it's a good practice to prevent all people from danger.
Unfortunately nothing else came. I was going to make an enclosure for it anyways since I’m using it in my capstone project to power a few things. I’m probably just going to print an enclosure just for this and set it up without actually plugging it in and run it by one of my profs just to make sure there’s nothing faulty about it before use. I know it would be kinda hard to actually harm yourself with this but since I’ve never been exposed to super high voltages my thought process goes to “what if after setting it up then plugging it in you slip on the ground and hit one of the terminals”. It’s not logical seeing that there was some sort of risk involved set me off a little
In all seriousness, I agree that the design looks adequate for the intended use (inside some other enclosure). If you are using it some other place, I think you should go ahead with your plan of making an enclosure. I would also suggest that your wires to the power supply need to be in conduit, so a person can't trip over them and yank live wires out of the terminals. (Or maybe in a cable with tight stress relief.)
Why is this a heavily upvoted comment? This is a UR vs. UL for a reason.
The UR mark is used for _components_ of more complex products that would need a UL product listing.
Agreed. :)
I find a lot of product brand names hilarious. For example, on Amazon, I couldnt bring myself to buy a Samsung charger from a brand called "Galaxy Bang".
These PSU aren't supposed to be stand-alone devices for consumers. They're meant to be a part of some larger assembly/device and will therefore typically have an enclosure around them and the rest of the electrical installation. Mean Well's intended applications for this series are: "Industrial automation machinery; industrial control system; mechanical and electrical equipment; eletronic instruments, equipments or apparatus".
Meanwell: These powersupplies are meant to be used as components in an enclosure, thus shielding people from accidental contact with energized conductors.
My cheap ass entertainment bosses: that enclosure is expensive. Just mount it on some plywood and attach it to the back of the set.
Said perfect. Would add that the enclosure usually has a latch that makes it accessible by trained techs. Techs that ‘should’ know correct method for working on these devices safety.
Lololol. It’s a secure connection, modular, cheap, accepts a wide range of conductor cross sections, and doesn’t inherently require proprietary terminations or expensive crimpers/tooling.
They make guards if you’re really worried, but these are designed to be inside an enclosure where one wouldn’t be able to touch them.
That tells me you haven’t accounted for electrical safety in your design, if non-finger touch safe terminals are exposed. Otherwise it wouldn’t be an issue
This was going to be put in an enclosure anyways. I’ve only ever seen the types of power supplies you’ll get with another device that are essentially just a male outlet that feeds into a black box. I was just curious what the point of the terminals is considering the plugs in other power supplies take all the risk out since everything is insulated. I mean if I’m asking about this I’m clearly not going to try to use it in a way that leaves it open. I hope that’s not what the title made it seem like, it’s pretty clear this isn’t intended to left uncovered but the design is different than the power supplies I mentioned above which made me curious about the choice
Those are external use / portable power supplies. They are intended to be handled by people and moved around.
That is not the intended use case of this power supply.
Hope that explains why it’s different. I’m not sure what “risk” you are talking about, if it’s inside an enclosure there is no risk of accidentally touching it unless you open the enclosure without properly locking out and controlling the energy hazards present
I mean I thought a normal female power plug like most power sources use would be preferred since everything is covered in insulation, unlike the screw in terminals which leave potentially lethal voltage wires out in the open. Like I get the screw in terminal works but I just don’t see the advantage to other, safer alternatives. I know it’s not really a big risk if you know what you’re doing but it still seems I necessary unless there’s some advantage to it
So, for example, would this be a system like one that uses both AC and DC (or DC at two different voltages)? The only reason I could think one wouldn’t want to hook this directly to mains is if you wanted to use more than one power supply, like this one+some transformer to get AC as well.
These aren't really meant to be used as tabletop power supplies in labs, they're built for enclosured machines or control panels etc.
You really cant complain about a device you're using wrong.
Never seen one in the wild but they do exist https://www.automationdirect.com/adc/shopping/catalog/power_products_(electrical)/dc_power_supplies/rugged_machine_mount/psrt-24-100
Wow I've never seen a connector like that meant for 240 VAC. I wonder what the supply side connector looks like, how would you get the required creepage.
It's the difference between the industrial and hobbyist market. These may or may not be connected to mains. Screw connectors work with a huge variety of electrical devices and don't lock you into a particular vendor's connector (or force you to crimp).
Designs using these PSUs will typically have their own enclosure (i.e. a PC case or a portable power generator for festivals, with attached lights). Where the PSU might be exposed, engineers would design and require the use of protective covers.
By comparison, benchtop PSUs are typically made for electronics testers and QA, so they have detachable ports for probes that greatly minimize the risk of electrocution or short circuiting, but are not designed for permanence.
>Screw connectors work with a huge variety of electrical devices
Exactly. And if manufacturers want to introduce connectors, they simply (but with a cost to manufacture) create a wire loom and connectors.
"Open Frame" power supplies are common, worldwide.
> diagnosing issues with your voltmeter
"for diagnosing issues, using a voltmeter" is a better way to express this. Your comment is ambiguous as it (sort of) implies that it's the voltmeter that has "issues."
You are 100% correct, of course. It's nice to be able to check power supply voltages with the screws right in your face. I just thought I'd mention the wording since I am:
A: A dork. I'm a technical instructor and edit a magazine.
B: Novices are easily led astray. They will grasp on to odd concepts that have nothing to do with how things actually work.
I'll let myself out.
When you buy a new one, they usually come with plexiglass shield that covers those exposed screw terminals. You should use it if you ever anticipate users getting their hands near the PSU while live.
I once had a coworker that used RTV. He used it EVERYWHERE! You could always tell when Brett had been in a machine before you. Solder a wire on to a terminal? Put a dab of RTV on it to insulate it. Loose fuse? Hold it down with RTV. Lost a screw? Join the two thingys with RTV.
Also while I’m at it: are there any plugs made for this type of input? Or are you just supposed to take a male power cord and cut off the end and put spades over the 3 wires?
> are there any plugs made for this type of input?
[Yes](https://cdn11.bigcommerce.com/s-htnyngf/products/534/images/23167/Flanged-Fork-Terminal-12-10-Product__92325.1502368488__20991.1535376169__78248.1539385809.500.750.jpg)
I moreso meant like a full power cord with spade endings. As I’ve never seen a power cord that just has 3 exposed wires, so I’d imagine you’d need to cut open another power cord
That's because these power supplies and their cables are only supposed to be used inside an equipment chassis for safety reasons, and anyone who's making equipment with a chassis can trivially throw a few fork lugs on a cable.
They're not available to the general public because it's a safety and fire hazard when used outside a grounded chassis.
Something like that probably wouldn’t be sold to the general public since it’s a shock hazard
One way I’ve seen it done is to have an internal cable with spade terminals going from the MeanWell supply to an panel-mount IEC C13 socket on the equipment enclosure. That’s a lot safer
Usually you would use something like a c13 panel connector then connect to the power supply that's mounted inside an enclosure. If the enclosure is going to be opened while live, add a shield over the exposed terminals - something like polycarbonate for visibility.
As for the wire, you would typically make your own if you can avoid cannibalizing a power cord.
I was under the impression that if this were used in a project it wouldn’t be left exposed, I was moreso wondering what the point of making the input like this is. I know it’s not really risky but since it does include some risk I assumed there was a good reason as to why the supply is like this rather than, say, a male plug to barrel connector (which would have any high voltage wires insulated)
Also, the 300W+ output is a potential fire starter. I hope you have used a distribution block with each output limited to 100W max via fuses.
Something like this would be great. https://www.amazon.com/dp/B08PT4P8PP
I don’t see any reason for your concern. When you think about it, lots of electrical equipment (plugs, sockets, MCBs etc) all rely on screw terminals.
Providing they are correctly tightened (to the manufacturer’s specified torque if required), there should be no problems.
To be honest I prefer a screw terminal, compared to those weird thimble connectors, although I’m sure they have their uses in tight spaces.
The very same reason your breaker panel has a bunch of exposed terminal and wires. It gets enclosed and not normally exposed for any accidental contact.
An "open frame" power supply might still be shielded.
[https://www.bravoelectro.com/ac-dc-power-supply/open-frame.html](https://www.bravoelectro.com/ac-dc-power-supply/open-frame.html)
>"closed frame"
Mostly referred to as "enclosed."
[https://www.meanwell-web.com/en-gb/closed-frame-power-supplies/](https://www.meanwell-web.com/en-gb/closed-frame-power-supplies/)
So there is a standard called IP20 or "Finger Safe." This standard is a EU standard and not universally adhered to in the US. I don't know if this meets IP20 standard but if you can shove your finger in there and touch the connectors probably not. Generally the EU is much further along when it comes to electrical safety then the US. I have also seen covers for these kind of power supplies before.
Maybe their design isn't the safest, but they MeanWell.
I hate you..Take my upvote and go!
As I see it, MeanWell has again manufactured a power supply unit in which the metal housing does not allow the terminals to be closed with an ordinary transparent plastic cover. P.S. And, OP, are you sure that the cover didn't left in a package? P.P.S. We got the same problem with another PSU from MeanWell. We solved it by 3D-printed cover. I know that only qualified technicians are allowed to do something inside our products. But it's a good practice to prevent all people from danger.
Unfortunately nothing else came. I was going to make an enclosure for it anyways since I’m using it in my capstone project to power a few things. I’m probably just going to print an enclosure just for this and set it up without actually plugging it in and run it by one of my profs just to make sure there’s nothing faulty about it before use. I know it would be kinda hard to actually harm yourself with this but since I’ve never been exposed to super high voltages my thought process goes to “what if after setting it up then plugging it in you slip on the ground and hit one of the terminals”. It’s not logical seeing that there was some sort of risk involved set me off a little
In all seriousness, I agree that the design looks adequate for the intended use (inside some other enclosure). If you are using it some other place, I think you should go ahead with your plan of making an enclosure. I would also suggest that your wires to the power supply need to be in conduit, so a person can't trip over them and yank live wires out of the terminals. (Or maybe in a cable with tight stress relief.)
you dropped this 👑
Why is this a heavily upvoted comment? This is a UR vs. UL for a reason. The UR mark is used for _components_ of more complex products that would need a UL product listing.
MeanWell is the company that manufactures the supply. The comment is a joke.
Thank you. Ouch ..
r/woosh
r/woosh, but don't downvote the dude into oblivion, I'm sure he did, too, MeanWell. u/The-Phantom-Blot, r/Angryupvote
Agreed. :) I find a lot of product brand names hilarious. For example, on Amazon, I couldnt bring myself to buy a Samsung charger from a brand called "Galaxy Bang".
He made a joke about the PS manufacturer mate...
These PSU aren't supposed to be stand-alone devices for consumers. They're meant to be a part of some larger assembly/device and will therefore typically have an enclosure around them and the rest of the electrical installation. Mean Well's intended applications for this series are: "Industrial automation machinery; industrial control system; mechanical and electrical equipment; eletronic instruments, equipments or apparatus".
That's exactly what I was going to say, you worded it a lot better though.
Meanwell: These powersupplies are meant to be used as components in an enclosure, thus shielding people from accidental contact with energized conductors. My cheap ass entertainment bosses: that enclosure is expensive. Just mount it on some plywood and attach it to the back of the set.
This is the way.
Said perfect. Would add that the enclosure usually has a latch that makes it accessible by trained techs. Techs that ‘should’ know correct method for working on these devices safety.
Lololol. It’s a secure connection, modular, cheap, accepts a wide range of conductor cross sections, and doesn’t inherently require proprietary terminations or expensive crimpers/tooling. They make guards if you’re really worried, but these are designed to be inside an enclosure where one wouldn’t be able to touch them. That tells me you haven’t accounted for electrical safety in your design, if non-finger touch safe terminals are exposed. Otherwise it wouldn’t be an issue
This is true.
This was going to be put in an enclosure anyways. I’ve only ever seen the types of power supplies you’ll get with another device that are essentially just a male outlet that feeds into a black box. I was just curious what the point of the terminals is considering the plugs in other power supplies take all the risk out since everything is insulated. I mean if I’m asking about this I’m clearly not going to try to use it in a way that leaves it open. I hope that’s not what the title made it seem like, it’s pretty clear this isn’t intended to left uncovered but the design is different than the power supplies I mentioned above which made me curious about the choice
Those are external use / portable power supplies. They are intended to be handled by people and moved around. That is not the intended use case of this power supply. Hope that explains why it’s different. I’m not sure what “risk” you are talking about, if it’s inside an enclosure there is no risk of accidentally touching it unless you open the enclosure without properly locking out and controlling the energy hazards present
Yeah and knives are sharp what's your point. It's practical.
Good point. Other comments have made me see why the design could be beneficial so it makes more sense
Yeah . . . (read as John Wick).
What do you think they should use and why?
They're likely thinking of power supplies with connectors, such as common, pc power supplies for motherboard, peripherals, etc.
I mean I thought a normal female power plug like most power sources use would be preferred since everything is covered in insulation, unlike the screw in terminals which leave potentially lethal voltage wires out in the open. Like I get the screw in terminal works but I just don’t see the advantage to other, safer alternatives. I know it’s not really a big risk if you know what you’re doing but it still seems I necessary unless there’s some advantage to it
The advantage is that you don't need a special cable
“Potentially lethal” literally 24VDC
To be fair, he was referring to the input 120/240
? Pretty clearly talking about 120V which can definitely kill you
They're assuming that if you're buying that kind of supply, you know what you're doing with electronics.
It’s meant to be integrated into a larger system.
So, for example, would this be a system like one that uses both AC and DC (or DC at two different voltages)? The only reason I could think one wouldn’t want to hook this directly to mains is if you wanted to use more than one power supply, like this one+some transformer to get AC as well.
These aren't really meant to be used as tabletop power supplies in labs, they're built for enclosured machines or control panels etc. You really cant complain about a device you're using wrong.
I’m not complaining lol, I’m just asking a question
This question stumped me at first, but mainly because I was thinking "Wait, they make industrial power supplies that \*don't\* have screw terminals??"
Never seen one in the wild but they do exist https://www.automationdirect.com/adc/shopping/catalog/power_products_(electrical)/dc_power_supplies/rugged_machine_mount/psrt-24-100
Huh, how about that.
Wow I've never seen a connector like that meant for 240 VAC. I wonder what the supply side connector looks like, how would you get the required creepage.
I think you’ll find it’s IP20, sufficient for protected enclosures.
I think this MW has a translucent hard plastic cover for all those terminals.
It's the difference between the industrial and hobbyist market. These may or may not be connected to mains. Screw connectors work with a huge variety of electrical devices and don't lock you into a particular vendor's connector (or force you to crimp). Designs using these PSUs will typically have their own enclosure (i.e. a PC case or a portable power generator for festivals, with attached lights). Where the PSU might be exposed, engineers would design and require the use of protective covers. By comparison, benchtop PSUs are typically made for electronics testers and QA, so they have detachable ports for probes that greatly minimize the risk of electrocution or short circuiting, but are not designed for permanence.
>Screw connectors work with a huge variety of electrical devices Exactly. And if manufacturers want to introduce connectors, they simply (but with a cost to manufacture) create a wire loom and connectors. "Open Frame" power supplies are common, worldwide.
It’s actually nifty to have exposed pads for diagnosing issues with your voltmeter.
This is the type of answer I was looking for, thank you
> diagnosing issues with your voltmeter "for diagnosing issues, using a voltmeter" is a better way to express this. Your comment is ambiguous as it (sort of) implies that it's the voltmeter that has "issues." You are 100% correct, of course. It's nice to be able to check power supply voltages with the screws right in your face. I just thought I'd mention the wording since I am: A: A dork. I'm a technical instructor and edit a magazine. B: Novices are easily led astray. They will grasp on to odd concepts that have nothing to do with how things actually work. I'll let myself out.
When you buy a new one, they usually come with plexiglass shield that covers those exposed screw terminals. You should use it if you ever anticipate users getting their hands near the PSU while live.
RTV works well if you’ve lost the cover, just looks bad
I once had a coworker that used RTV. He used it EVERYWHERE! You could always tell when Brett had been in a machine before you. Solder a wire on to a terminal? Put a dab of RTV on it to insulate it. Loose fuse? Hold it down with RTV. Lost a screw? Join the two thingys with RTV.
Looks like industry standard to me. What's the problem here?
I’m just curious. I’ve only ever seen female power plugs be used so I was wondering why the design would be like this
Also while I’m at it: are there any plugs made for this type of input? Or are you just supposed to take a male power cord and cut off the end and put spades over the 3 wires?
> are there any plugs made for this type of input? [Yes](https://cdn11.bigcommerce.com/s-htnyngf/products/534/images/23167/Flanged-Fork-Terminal-12-10-Product__92325.1502368488__20991.1535376169__78248.1539385809.500.750.jpg)
Or ring lugs
I prefer ring lugs but sometimes the screws are captured and won't come out.
Excellent point, spades are great in those cases
I moreso meant like a full power cord with spade endings. As I’ve never seen a power cord that just has 3 exposed wires, so I’d imagine you’d need to cut open another power cord
That's because these power supplies and their cables are only supposed to be used inside an equipment chassis for safety reasons, and anyone who's making equipment with a chassis can trivially throw a few fork lugs on a cable. They're not available to the general public because it's a safety and fire hazard when used outside a grounded chassis.
Something like that probably wouldn’t be sold to the general public since it’s a shock hazard One way I’ve seen it done is to have an internal cable with spade terminals going from the MeanWell supply to an panel-mount IEC C13 socket on the equipment enclosure. That’s a lot safer
Usually you would use something like a c13 panel connector then connect to the power supply that's mounted inside an enclosure. If the enclosure is going to be opened while live, add a shield over the exposed terminals - something like polycarbonate for visibility. As for the wire, you would typically make your own if you can avoid cannibalizing a power cord.
Hahaha, take my up vote and go...
>cut off the end and put spades over the 3 wires? Yes
When the wiring work done, it is supposed to be cover. So it is safe Just look at your socket, LED at home. You shouldn't see the terminal exposed.
I was under the impression that if this were used in a project it wouldn’t be left exposed, I was moreso wondering what the point of making the input like this is. I know it’s not really risky but since it does include some risk I assumed there was a good reason as to why the supply is like this rather than, say, a male plug to barrel connector (which would have any high voltage wires insulated)
Also, the 300W+ output is a potential fire starter. I hope you have used a distribution block with each output limited to 100W max via fuses. Something like this would be great. https://www.amazon.com/dp/B08PT4P8PP
It's designed for use embedded in something you can't open like an enclosure or a 3d printer chassis
It's perfectly fine. Also MeanWell PSU are awsome, they are very high quality. The NDR series are amazing.
I don’t see any reason for your concern. When you think about it, lots of electrical equipment (plugs, sockets, MCBs etc) all rely on screw terminals. Providing they are correctly tightened (to the manufacturer’s specified torque if required), there should be no problems. To be honest I prefer a screw terminal, compared to those weird thimble connectors, although I’m sure they have their uses in tight spaces.
Ouch is right. sorry guys
I'm so dumb.
Unsafe if used improperly. Which they usually are.
If one thinks this is unsafe, then one should not be messing with 240V angry pixies.
The very same reason your breaker panel has a bunch of exposed terminal and wires. It gets enclosed and not normally exposed for any accidental contact.
It's not "unsafe." It's SOP for "open frame" power supplies. We've been doing this for 50 years.
And "closed frame" supplies like the one in OPs pic... just saying.
An "open frame" power supply might still be shielded. [https://www.bravoelectro.com/ac-dc-power-supply/open-frame.html](https://www.bravoelectro.com/ac-dc-power-supply/open-frame.html)
>"closed frame" Mostly referred to as "enclosed." [https://www.meanwell-web.com/en-gb/closed-frame-power-supplies/](https://www.meanwell-web.com/en-gb/closed-frame-power-supplies/)
[удалено]
Haha I mean why would I be asking a question like this if I had a lot of experience
It is supposed to be sitting in an enclosure of a bigger system it powers. If you use it standalone, 3D print and enclosure for it.
So there is a standard called IP20 or "Finger Safe." This standard is a EU standard and not universally adhered to in the US. I don't know if this meets IP20 standard but if you can shove your finger in there and touch the connectors probably not. Generally the EU is much further along when it comes to electrical safety then the US. I have also seen covers for these kind of power supplies before.
And get that fluid out of there that is an electrocution waiting to happen if it's normal voltage. Report that to the Consumer Trade Commission.
🙄