Square D bonding

Hello everybody, this is a tight box and an older one. I was wondering if anybody could confirm to me the box is bonded. So old no green screw. The label is hard to read and I’m not sure if one of the flatheads in the bus bar is a ground screw. Was hoping an electrical guru might know. Square D panel

It doesn’t appear to be bonded via a bonding screw. The label info is inconclusive as to which hole is to be used for the MBJ. There are several other issues like that shoemaker neutral lug on the upper left of the neutral bar to make further evaluation by a sparky needed. An watch out for those large energized partial copper lugs bolted to the bus bar.


This metal plate has a tamper resistant (one-way) screw, maybe a bonding strap.

Did your outlets test OK?

That looks like the GEC, don’t think I’ve ever seen a one way sheet metal screw for that before. Seeing crooked buss bars and past generator hook ups always make me look harder, and there is nearly always something that needs further evaluation/correction.

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Yeah I saw those lol. Are those ok in there?

Yes they were all wired correctly. Some of them were loose due to age. Also a handful had loose connections, the tester would show ungrounded-correct-ungrounded. I think that was an issue at the receptacles though. The majority were good.

There is no reason for them to be there, looks like someone had tapped of the bus at one point with those. I would wonder since those are factory bolts on the bus if they had been re-tightened to the proper torque also they could be a shock hazard if you’re poking around there and not realizing that they are energized.


There was a propane generator outside the home. I don’t have any training on them but it was locked anyways and there was no key. I don’t know if it was in use. The panel was just opposite this panel at the exterior. I don’t know if that has anything to do with these? I thought they were kind of alarming but would only be an issue for people in the panel. Wasn’t planning on writing up.

Is that neutral tap improper? I could tell it was added after the fact. I don’t know if that’s allowed ever or what the standards are.

I thought those were the remnants of a generator hook up. I’ve seen a couple dot setups that were wired in that way, always lacking any safe lockout.

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If the nuetral and ground were not bonded the three light tester would read no ground.

The panel is old so it’s hard to say if that is a listed terminal for the neutral connection. Let’s say that it is the correct terminal for that panel there is no way that it is installed correctly.


Awesome thanks

I read the question as being about “panel” bonding, not bonding neutral and grounding conductors, which can be seen in one of the pictures. If the grounding and neutral conductors are tied together anywhere (the panel whether the “green” screw is installed, or even a boot leg ground on the receptacle) a three light tester will show the circuit to be grounded.


It looks like all of the branch circuits are NM cable or SE cable so you’re correct the EGC and the neutrals would be connected together on the same bus within the panel. If there is no bonding screw or other MBJ then it’s possible that the metal enclosure is not bonded. This would be a problem if there were branch circuits or feeders that utilized metallic cables like AC cable or metal raceways where the raceway or cable jacket were being used as the EGC.

Robert (Bob) Kenney, CMI® MD Lic.# 31044rkenneyCertified Master Inspector®


The receptacles could still show wired correctly even without the bond screw. Receptacles can also show as grounded without a GEC and an electrode like a rod.

Not true.


If you are referring to a bootleg ground that is not that common. The light on the three light tester that indicates no ground when it is extinguished is lit by a connection to Hot and Ground at the outlet. If the ground is not bonded to the neutral at some point in the circuit (as at the panel) the light will not light indicating an open ground.

If you have some other scenario in mind you need to specify what it is. All you’ve done is make claims.

That’s correct. In this installation since it’s NM cable they’re connected at the neutral bar.

Yes the grounds and neutrals were bonded. My question was regarding the panel bonding to the ground. Sorry if there was confusion. 3 light tester doesn’t show anything regarding that.