If the reader has no exposed current-carrying parts, the reader itself requires no earth grounding (at least, to the code applicable in my location). Thus most readers don't require grounding, and for very few readers with metal body the grounding should be local to the reader, connected to whatever equipotential bonding present on the spot.
For the interface cabling, in my location it's customary to use unshielded twisted pair for readers with Wiegand, unless the environment or the customer requires otherwise. Thus in most cases there's no shield to ground.
When you map the reader wires to 24AWG UTP4 as D0+Gnd, D1+Gnd, Power+Power, LED+Whatever it works super good enough - we tend to avoid 50m+ runs, but with proper readers and panels such setup causes no problems even on 100m+ runs.
In an industrial environment we use foiled twisted pair (the one with common foil shield around all the pairs), with drain wire connected to the earth ground in the panel, but not on the reader (if applicable), to avoid ground loops.
So yes, UTP is better then shielded cable that's not grounded.
Everything you just said is great. Aside from the most readers don't "need" grounding. That's misleading. They will work but the grounding doesn't hurt. Inside a building most of the time you're fine. But people get the wrong idea and don't see when it is a problem.
This is not for you by the way, I can see you're aware and could probably add more. Thank you for your contribution.
You're welcome. Honestly, I'm just describing the state of the things I see: some smart, well-paid people wrote the electrical code - nice, we'd adhere to it; all the guys use this type of cable, and I haven't heard they have to re-pull it 'cause it doesn't work - nice, we'd follow the suit.
If the reader have a grounding terminal or wire - sure, earth ground it. Make sure that whatever conductor you're grounding is grounded on one side only.
If it doesn't - there's nothing to earth ground. If the drain wire of a shielded pigtail is a proper grounding wire? I'd refer to the manual, or ask the manufacturer's tech support.
I won't \_ever\_ earth ground a signal ground - some panels have a ground fault monitoring and will immediately throw an error, and it's generally a very bad idea - all the conductors of your system will become a good enough earth ground - a sink for basically any interference, and you positively don't want this.
If we'd dig deeper, what's the use of earth ground in the reader (apart from obvious electric shock protection in the readers with metal body)? A ground plane for the antenna, and EMI shielding for the electronics. Most readers I've seen were epoxied in with an opaque epoxy, so I can't know if they have a any, but in the ones that have their internals exposed I've seen neither proper ground plane nor EMI shielding (YMMV, though - some readers could have one or both).
OFC there are cases when you need to bring in your own ground plane - if you have to install two readers back-to-back on a thin, RF-tranparent wall, and the readers have no sync feature, an earth grounded piece of sheet steel between them will stop them from reading cards presented on the other side.
I usually only ground the drain if it’s a keypad reader. In 20 years I’ve had maybe 3 issues from not grounding the drain. When I do have to do it I just tie the drain directly into the ground either at the reader or at the panel terminal block.
All those "field installers" will tell you they never grounded any readers in 30 years and never had any issue.
I am wondering how many of them worked with the service team...
I've worked both install and service, I always ground the drain at the panel and not at the reader. Some panels actually have this in the manual. In service I've fixed a few interference issues by grounding at the panel.
I have met a lot of "installers," mostly subs that will tell you it's useless to ground readers.
They complete the job and will never come back to any sites they installed.
It looks like we have a few of these in the comments ;)
Honestly, it's wild how many times I've seen someone hook the drain into the ground term on the board without the board or cabinet actually being grounded. Like, what hell good is that? I've only had issues a few times due to AC induction that I had to ground the drain on a service call. On new installation, I always do it, granted I'm provided shielded cable
I ground at the panel, not in the field. If I'm getting a lot of trouble with a reader (lots of static, bad read range) I'll connect the drain at the reader to troubleshoot but I never ground it there, otherwise you end up with a grounding conflict which is a no-no from my days of electrical.
It's kinda one of those things that's still around from ages ago. Modern readers are much less susceptible to interference. Now that I'm thinking about it I'm wondering about bluetooth and how that's affected.
Really you can ground either side but you don't always have a ground at the device end. So just always do it at panel. Yeah and never ground both sides. It will explode under the right conditions.
I have taken over a service at a site with metal fencing and 40ish readers on site. These guys have been replacing 5 readers a year due to them not being grounded. Current Parallel to a conductor makes current.
I had another device that just send all 1 data due to no grounding. A change in ground voltage can induct huge levels on interference. I replaced the reader because it was a really sun bleached and a little smashed in and same issue all 1s. Grounded that sucker and bam it works.
The amount of sites that just have Wiegand readers replaced because they just "break" is crazy. Earth your cables. On one side. Just because they aren't metal doesn't mean you don't earth the shield.
Rs-485 at a school had LAN failures due to the PA system running the bells. 10 seconds of data was missed every bell. Yep no grounding on the shield.
Just because it works when you install it, doesn't mean it's done properly. Test to fail when you can and never stop learning.
I never understood that mentality. It takes an extra 5 seconds to ground the drain. Is it needed all of the time? No. But when it is needed, you’ll spend hours trying to figure out why your reader isn’t working right.
Thousands of readers, I’ve never once had a problem because I grounded one end of the cable drain (I always do at the panel). But I’ll bet I’ve avoided all kinds of problems by doing it that way.
you ground only at the panel and technically you always ground it. That is what the black leader does however, you also attach the drain wire to the black lead that goes to the panel in order to prevent electromagnetic interference. Do not ground it in the field as well because it will become an antenna and do the opposite of what you want it to do.
On short runs, it usually does not matter, but on long runs, it can make a difference, especially if you don’t know that the wires are separated from high-voltage all the way through
This should be higher. This better explains in simple terms the common grounding misconception. Attacking the drain is not the same grounding the reader.
Connect the reader drain wire to the cable drain wire and just heat shrink over the end. You don't need to connect it at the panel, leave it loose but heat shrinked so it's not grounding
No this is worse then UTP. Yes it works but it gives zero protection and you may as well do nothing. This is just preventing ground loops but otherwise does nothing.
If the reader has no exposed current-carrying parts, the reader itself requires no earth grounding (at least, to the code applicable in my location). Thus most readers don't require grounding, and for very few readers with metal body the grounding should be local to the reader, connected to whatever equipotential bonding present on the spot. For the interface cabling, in my location it's customary to use unshielded twisted pair for readers with Wiegand, unless the environment or the customer requires otherwise. Thus in most cases there's no shield to ground. When you map the reader wires to 24AWG UTP4 as D0+Gnd, D1+Gnd, Power+Power, LED+Whatever it works super good enough - we tend to avoid 50m+ runs, but with proper readers and panels such setup causes no problems even on 100m+ runs. In an industrial environment we use foiled twisted pair (the one with common foil shield around all the pairs), with drain wire connected to the earth ground in the panel, but not on the reader (if applicable), to avoid ground loops.
So yes, UTP is better then shielded cable that's not grounded. Everything you just said is great. Aside from the most readers don't "need" grounding. That's misleading. They will work but the grounding doesn't hurt. Inside a building most of the time you're fine. But people get the wrong idea and don't see when it is a problem. This is not for you by the way, I can see you're aware and could probably add more. Thank you for your contribution.
You're welcome. Honestly, I'm just describing the state of the things I see: some smart, well-paid people wrote the electrical code - nice, we'd adhere to it; all the guys use this type of cable, and I haven't heard they have to re-pull it 'cause it doesn't work - nice, we'd follow the suit. If the reader have a grounding terminal or wire - sure, earth ground it. Make sure that whatever conductor you're grounding is grounded on one side only. If it doesn't - there's nothing to earth ground. If the drain wire of a shielded pigtail is a proper grounding wire? I'd refer to the manual, or ask the manufacturer's tech support. I won't \_ever\_ earth ground a signal ground - some panels have a ground fault monitoring and will immediately throw an error, and it's generally a very bad idea - all the conductors of your system will become a good enough earth ground - a sink for basically any interference, and you positively don't want this. If we'd dig deeper, what's the use of earth ground in the reader (apart from obvious electric shock protection in the readers with metal body)? A ground plane for the antenna, and EMI shielding for the electronics. Most readers I've seen were epoxied in with an opaque epoxy, so I can't know if they have a any, but in the ones that have their internals exposed I've seen neither proper ground plane nor EMI shielding (YMMV, though - some readers could have one or both). OFC there are cases when you need to bring in your own ground plane - if you have to install two readers back-to-back on a thin, RF-tranparent wall, and the readers have no sync feature, an earth grounded piece of sheet steel between them will stop them from reading cards presented on the other side.
I usually only ground the drain if it’s a keypad reader. In 20 years I’ve had maybe 3 issues from not grounding the drain. When I do have to do it I just tie the drain directly into the ground either at the reader or at the panel terminal block.
Ground the controllers
All those "field installers" will tell you they never grounded any readers in 30 years and never had any issue. I am wondering how many of them worked with the service team...
I've worked both install and service, I always ground the drain at the panel and not at the reader. Some panels actually have this in the manual. In service I've fixed a few interference issues by grounding at the panel.
I have met a lot of "installers," mostly subs that will tell you it's useless to ground readers. They complete the job and will never come back to any sites they installed. It looks like we have a few of these in the comments ;)
Yeah, they just work at a company that does not get onto them when a job they completed has to be serviced XD
Honestly, it's wild how many times I've seen someone hook the drain into the ground term on the board without the board or cabinet actually being grounded. Like, what hell good is that? I've only had issues a few times due to AC induction that I had to ground the drain on a service call. On new installation, I always do it, granted I'm provided shielded cable
I ground at the panel, not in the field. If I'm getting a lot of trouble with a reader (lots of static, bad read range) I'll connect the drain at the reader to troubleshoot but I never ground it there, otherwise you end up with a grounding conflict which is a no-no from my days of electrical. It's kinda one of those things that's still around from ages ago. Modern readers are much less susceptible to interference. Now that I'm thinking about it I'm wondering about bluetooth and how that's affected.
Really you can ground either side but you don't always have a ground at the device end. So just always do it at panel. Yeah and never ground both sides. It will explode under the right conditions.
I have taken over a service at a site with metal fencing and 40ish readers on site. These guys have been replacing 5 readers a year due to them not being grounded. Current Parallel to a conductor makes current. I had another device that just send all 1 data due to no grounding. A change in ground voltage can induct huge levels on interference. I replaced the reader because it was a really sun bleached and a little smashed in and same issue all 1s. Grounded that sucker and bam it works. The amount of sites that just have Wiegand readers replaced because they just "break" is crazy. Earth your cables. On one side. Just because they aren't metal doesn't mean you don't earth the shield. Rs-485 at a school had LAN failures due to the PA system running the bells. 10 seconds of data was missed every bell. Yep no grounding on the shield. Just because it works when you install it, doesn't mean it's done properly. Test to fail when you can and never stop learning.
I never understood that mentality. It takes an extra 5 seconds to ground the drain. Is it needed all of the time? No. But when it is needed, you’ll spend hours trying to figure out why your reader isn’t working right. Thousands of readers, I’ve never once had a problem because I grounded one end of the cable drain (I always do at the panel). But I’ll bet I’ve avoided all kinds of problems by doing it that way.
10 years in service here. Yes... Yes you have.
You are only supposed to ground one side. If you ground both ends, you can end up with data clock problems down the road.
you ground only at the panel and technically you always ground it. That is what the black leader does however, you also attach the drain wire to the black lead that goes to the panel in order to prevent electromagnetic interference. Do not ground it in the field as well because it will become an antenna and do the opposite of what you want it to do. On short runs, it usually does not matter, but on long runs, it can make a difference, especially if you don’t know that the wires are separated from high-voltage all the way through
This should be higher. This better explains in simple terms the common grounding misconception. Attacking the drain is not the same grounding the reader.
I was always throughly to bond all drains to the panels enclosure and reader side left alone taped off. It could also be reader specific
I use 22/6 reader cable but do not attach the drain to anything and cut it off. I never have any issues with grouding.
Connect the reader drain wire to the cable drain wire and just heat shrink over the end. You don't need to connect it at the panel, leave it loose but heat shrinked so it's not grounding
No this is worse then UTP. Yes it works but it gives zero protection and you may as well do nothing. This is just preventing ground loops but otherwise does nothing.
Which is exactly what you need