Double tapped neutral

Hey Guys,

Help me out a little here please, with this double tapped neutral thing.

I see double tapped neutrals, and grounds a lot.

So I understand why double tapped hots are bad, because you can have two branch circuits on a single breaker which can be two many amps. But this doesn’t apply to grounds and neutrals.

Is double tapping grounds and neutrals bad only because more than one wire doesn’t fit under the screw? And if so, some ground/neutral bars have big screws and little screws, are the big screws made to allow for double tapping?

Help!

http://ecatalog.squared.com/pubs/Electrical%20Distribution/Panelboards/0100DB0705.pdf

The code rule is each neutral in a hole by itself.

Two hots on a single breaker are now a single circuit.

Thanks Guys!

Double grounds are ok if the hole is listed as such. One neutral per hole always.

Ok I got it. funny thing is that the code inspectors pass double tapped neutrals very often.

Neutrals are also a current carrying conductor. With two conductors under a terminal rated for one conductor the wires could come loose and begin to arc.

You can have 2 branch circuits on the same breaker.

But the breaker must be rated for two conductor. If not you can pig tail the two circuits together.

Same for neutral and grounds together
An individual terminal should be provided for the connection of each branch-circuit neutral conductor. When the neutral is disconnected, the objective is to still have the equipment ground connected to the grounding electrode. If both the neutral and grounded conductor is under the same terminal, this cannot be accomplished.

You really need to look for all 3 wire circuits that share a neutral. It’s extremely important that this particular neutral is on its own. If that neutral comes loose, the circuit can go from 120 V up to 240 V depending on other loads on that circuit. Very hazardous!

You see it a lot because this was not always the adopted rule.

Check your dates. Nothing says you must upgrade it. But you can recommend it.

What do you mean by the statement “this was not always the adopted rule”?

I’ve talked with “Seasoned” electricians and their comment was if the equipment ground was in the same terminal as the neutral, the circuit would still be isolated from other branch circuits meeting the code. Don’t yell at me…Just Saying.

I see this every day. Especially in old panels where there were screws at the bottom of the panel and no terminal blocks and even in panels from the 80’s. Newer construction (2000 and beyond) are typically wired correctly.

What code cycle first addressed the double tapping of grounded conductors?

Lots of houses passed inspection with this issue before that.

TN Law does not require it to be repaired on site.

Panels were built to UL 67.

It was never permitted to your more than 2 Neutral under a lug.

IOW

If the electrician followed the mfgs instructions as required by the NEC it never would have happened.

The intent of adding it to the 2002 NEC -

As Michael stated the wording was added to the NEC because not many installers or inspectors knew that the single neutral/hole was already part of the listing of the panelboard for decades prior to the 2002 NEC.

So grounds are allowed to be double tapped? (according to the image posted)

-Carl

Grounds can be doubled or tripled if in accordance with the labeling requirements, ie size, material etc.

Well I have news. It doesn’t mean a hilll of beans what the “code” is, was or gonna be…

The AHJ can “adopt” a code, re-interpit the code, or “opt out” of a code.
Till you talk to “the man” you don’t have clue what is the required code.

Trust me. It gets way out there sometimes.
As you can imagine, I seldom “hold back” on much of anything. But I don’t make crap up. If there is a problem with a dbl tapped grounded conductor, I’m going to “show you” that adverse issue involved. I also get on the phone with those that make those decisions. Then I “know”.