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I'm installing a Plug-On-Neutral (PON) main panel. There is a screw with a label indicating that if I need to bond the ground to neutral, tighten to 40lbs.

Now I know main panels generally have the ground and neutral bonded, and it appears that they all are, but I am assuming something is not. Is it the PON neutral bars specifically that are not currently bonded? Is there any reason, for a main panel install, that I would not want to tighten this screw?

As a side note to someone with a higher reputation. It seems like a "Plug-On-Neutral" tag is warranted.

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  • As a side note to you, disambiguate your Three Letter Acronyms (TLAs) when you pull them out, not as a side note at the end.
    – Ecnerwal
    Jul 3 '20 at 14:57
  • Perhaps. But PON has been around for a while. I think it’d pretty well known. You don’t expect me to disambiguate “lbs” as well do you?
    – mreff555
    Jul 3 '20 at 15:02
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    It's a torque measurement, so it's either inch-pounds or foot-pounds, not bare pounds. Being an electrical panel screw, most likely inch-pounds.
    – Ecnerwal
    Jul 3 '20 at 15:09
  • Yeah, it didn’t specify but 40ft lbs would snap a 1/4” screw.
    – mreff555
    Jul 3 '20 at 15:10
  • Most torque measurements are in “lb inch” I don’t know why they are not listed as “inch lb” make sure you are using the proper torque at ~25 foot lbs the 32 pitch screw connecting to the sheet metal will strip out
    – Ed Beal
    Jul 3 '20 at 15:26
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On a main panel, you always bond the neutral and ground. Just because it's a PON panel doesn't change that. The reason they don't have it "factory bonded" is because sometimes they get used as a sub-panel. This is becoming the case more often. If the panel is covered by a separate disconnect, which is becoming required, then the main panel gets treated like a sub-panel.

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  • That’s what I thought. I had never done a PON install and wanted to verify.
    – mreff555
    Jul 3 '20 at 15:03
  • So if one would add a separate external disconnect below the meter, would one have to remove the neutral to ground bond in the panel? Jul 3 '20 at 17:14
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    Jim: There may be more involved than that. Adding a disconnect between the meter and the panel makes the panel be treated as a sub-panel. The neutral and ground bonding would be removed. The problem is often times, the main panel ground buss bars and neutral buss bars are the same or used indiscriminately for neutrals and grounds. That would have to be sorted out so you could properly isolate the neutral. Jul 3 '20 at 17:19
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    By far it's best practice to put the neutral on the neutral buss bar and the grounds on separate buss bars bonded to the panel can itself. But it often wasn't done that way in the past. Some older panels don't even have separate ground and neutral buss bars, you'd have to buy a ground buss and install it in the panel. Jul 3 '20 at 17:21
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There is no difference between plug-on neutral and regular panels; plug-on-neutral is just an alternate way to pick up the neutral instead of a pigtail.

As such it has no bearing on the question of neutral-ground bonding. Main panels must be bonded; subpanels must not. Also, you are not required to use the provided bonding screw, and you can run a heavy ground wire instead if you prefer to have something you can put a clamp meter around.

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  • Based on the other answers, I think you are wrong. The PON rails don’t have holes to attach wires to. I think that screw is how you bond them.
    – mreff555
    Jul 4 '20 at 1:02
  • @mreff All neutral bars are cross-connected together, so both PoN bars and all screw bars are tied. Connecting to any of them is connecting to all of them. So an equipotential bond can indeed go to the neutral screw bars. Jul 4 '20 at 4:18
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With GFCI’s being required in all garage receptacles I have used PON panels for subs it just makes sense. remove the bonding screw For a sub (plug on neutral) are a bit faster to wire and our inspectors like them so inspections go quicker. You can use old style breakers in a pon but pon will not fit in a old style panel.

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