Square D Neutral Double Tap

[mmurphy4]

I inspected a Square D panel that was approved for two wires. My question is, if the breakers are approved for two wires, does that mean two wires could be under each lug at the Neutral buss bar? There was double tapping at the buss bar. I recommended it to be further evaluated by an electrician. Now the homeowner is calling telling me that it is approved to have two wires under each lug. This only applies to the breaker itself correct? or does this include the buss bar as well?

[Jim Port]

The breakers being listed for use with 2 wires is a only for the breakers. The neutral buss is a different matter. The buss can accept 2 grounding wires under one screw if they are within the size range listed. Grounded or neutral wires are limited to one per terminal. no sharing of the terminal with grounded and grounding conductors.

Article 408.41 spells this out regarding the neutrals. Previously it was in the listing and labeling instructions and on the label inside the panel.

[Brian E. Kelly]

Two nuetrals under one lug was ok and the norm for many years. I can not recall when the NEC no longer allowed this condition, but am sure some one will be able to tell us. But current standards do not allow two nuetrals under one lug.

You did your job by telling the client of the condition you found, if they want to tell you it is ok, fine.

[David P. OKeefe]

Originally Posted by bkelly2

Two nuetrals under one lug was ok and the norm for many years. I can not recall when the NEC no longer allowed this condition, but am sure some one will be able to tell us. But current standards do not allow two nuetrals under one lug.

You did your job by telling the client of the condition you found, if they want to tell you it is ok, fine.

It was the norm, but I don't think it was ever OK. It was/is OK to have two grounding wires under the same lug but not two grounded (neutral) wires. I think the code was misinterpreted, and it was believed to be OK to have two neutrals together. But like you said, someone will be able to tell us and in ether case it is not OK now.

[Michael Larson]

It's been discussed many times.

Here is an earlier thread.

http://www.nachi.org/forum/f19/calli...any-gru-22075/

[Christopher Currins]

http://www2.sea.siemens.com/NR/rdonl...rminations.pdf

[Jeffrey R. Pope]

Originally Posted by bkelly2

But current standards do not allow two nuetrals under one lug.

. . . except where allowed by the equipment manufacturer for circuits with parallel conductors.

Most panels are listed for a single neutral at each terminal connection. I have never seen a Square D panel listed to accept more than one neutral conductor.

[Brian E. Kelly]

Originally Posted by jpope

. . . except where allowed by the equipment manufacturer for circuits with parallel conductors.

Most panels are listed for a single neutral at each terminal connection. I have never seen a Square D panel listed to accept more than one neutral conductor.

Dangit Jeff, I decided I have been doing this long enough now that I should probably start calling the Neutrals by their correct term ie the Grounded Conductors, and now you spring the parallel conductors on me.

[Jeffrey R. Pope]

I just don't want you getting too comfortable. . .

[mmurphy4]

Thanks guys,
I wasnt sure if the manufacturer allowed it or not. Thanks for the help Mr. Pope. It was reassuring to hear that you have never seen a Square D panel that allowed this. Told them its not up to the 2002 NEC code, but is only a hazard when working on one of the two double tapped circuits. I'll let them figure out what to do about it.

[mmurphy4]

Ok seriously, I've gotten 4 phone calls already about this situation. The electrician, both realtors, the home owner. I just keep telling them, it is potentially unsafe when someone is working on one of those circuits, it is safe under normal usage. I am somewhat new, do they always have such a fit when this is called out?

[Jeffrey R. Pope]

Tell them that the electrician has the final say, so long as he puts it in writing. Move on.

[Frank P. Newman]

I find this condition in the majority of the homes I inspect. I always write it up, but have never had a follow-up call about it. Maybe they are just ignoring me?

[Peter Foxe Smothers]

Originally Posted by mmurphy4

Thanks guys,
I wasnt sure if the manufacturer allowed it or not. Thanks for the help Mr. Pope. It was reassuring to hear that you have never seen a Square D panel that allowed this. Told them its not up to the 2002 NEC code, but is only a hazard when working on one of the two double tapped circuits. I'll let them figure out what to do about it.

Also, do not site code during your home inspection or in your inspection report. Your doing a general home inspection not a code inspection. Current building practices or current building standards are both good substitutes for the code word.

[mmurphy4]

Thanks for the advice. I did not put the code into the report. The buyer asked specifically if it was up to code so I told him. I dont really know specific building codes unless I do research on a topic, which I did on this one.