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Allowable double taps


Robert E Lee
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Thanks so much Jim. On my last inspection yesterday I called out a double tap connection on a GE breaker, the homeowner indicated that was how the electrician wired the panel. When talking with the electrical contractor he of course was sure it was correct (but was going to check with his supplier). I've attached a photo that I included in the report.

Robert E Lee

GENERAL Home Inspections, Inc

Rochester, MN

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Originally posted by Bain

Splendidly done, Jim. Can I have your permission to give a copy of this to intransigent sellers, electricians, and/or seller's realtors?

John

You can use it as a handout as long as you don't change anything and as long as you leave my name and copyright on it. Don't publish it in any books or periodicals.

- Jim Katen, Oregon

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"Some (not all) Square D breakers are designed to accept two wires."

An important point. I think most HI's would be amazed to look through a full Square D catalog and see the incredible number of different breakers they manufacture (as do the other big manufacturers). It's mind-boggling. Only one or two types are rated for this use, and not all sizes of those types.

Jim, I'm curious...what's your personal opinion of double-tap rated breakers? Good idea? Bad? I admit I find this on my list of currently blessed electrical ideas that I don't like, along with multi-wire circuits, back-stabbed devices, split bus panels, the 6 movements rule in place of a real main breaker, existing AFCI's, etc.

Brian G.

Electrical Curmudgeon [:-grumpy]

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Brian,

I wouldn't presume to answer for Jim, but my two cents...

Circuit abuse can happen anywhere! If you add a new fixture or receptacle, is it better to add a junction box and wire-nut 3 hots, 3 neutrals, and 3 grounds, or to run a cable to the panel and secure 3 serparate wires under terminals designed to hold those wires very securely? I've posted a close-up of the Square-D version a couple of times, and there is no doubt it is well designed to hold two conductors.

Could you be tempted to overload the breaker this way? Of course, but I see little difference between that and an idiot with a box of wire-nuts. The breaker can look after itself.

I see far more double-taps on breakers not designed for them, than I do on the breakers that are. Is it safer to tempt someone to do the double nasty thing or to give them a viable option?

I am definitley with you on the split-bus panels! More than a single throw may be needed in some special circumstances such as large services, and hence the limit of six or more than one. I think the manufacturers took adavntage of the code to produce a slightly cheaper product and the split-bus panel is the unintended bastard son. Whenever they get together, the NEC should insist the manufacturers wear a condom!

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Originally posted by Brian G.

. . .

Jim, I'm curious...what's your personal opinion of double-tap rated breakers? Good idea? Bad? I admit I find this on my list of currently blessed electrical ideas that I don't like, along with multi-wire circuits, back-stabbed devices, split bus panels, the 6 movements rule in place of a real main breaker, existing AFCI's, etc.

Brian G.

Electrical Curmudgeon [:-grumpy]

I feel no ill will toward the double tap rated breakers. They seem to work just fine.

Multi-wire circuits have a long and proud history. Plus I like the elegance of them. And after all, the entire service is really one big multi-wire circuit, no?

Back-stab devices suck. Their entire raison d'etre is to encourage quick, cheap work and lower the bottom line. On the other hand, I love those breakers where you stick the stripped wire in the little hole and then tighten the screw. Nice design.

Split bus panels were a poor idea. Too easy to overload them.

The 6 movement rule is ok by me. Without it, a lot of installations would be very expensive to expand.

Existing AFCIs are a cruel and expensive joke.

- Jim Katen, Oregon

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Originally posted by Jim Katen

I feel no ill will toward the double tap rated breakers. They seem to work just fine.

I have no particular adverse experience with them to this point, but the basic idea of putting two circuits on one breaker bothers me. I think tandem breakers make more sense if you need to get the extra circuits somehow. Why wasn't that good enough anymore? These things are purely about economics, not improving anything (like safety).

Multi-wire circuits have a long and proud history. Plus I like the elegance of them. And after all, the entire service is really one big multi-wire circuit, no?

(edited due to brain cramp)Okay, I missed the idea at first but I see what you're saying. Is that a good idea in branch wiring though? Where else are you allowed (much less required) to tie the handles of two 110v circuits together?

I think they're unnecessarily complicating, and offer no real benefit to balance to the equation. From surfing various boards I know this thing confuses a lot of HI's and electricians. Just pull a second 12/2 WG, set a second box, and put in two single recepticles. Far simpler, little extra expense, and the safest possible arrangement (now and later).

The 6 movement rule is ok by me. Without it, a lot of installations would be very expensive to expand.

Could you give me an example? I realize a main isn't needed in every panel and every situation, I just think that where one is needed one should be required, not six. I see that rule as a dinosaur where residential service equipment is concerned.

I think all three of these fall into "because we can" rather than "because we should".

Brian G.

A Man With No Strong Opinions [:-dev3]

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Originally posted by kurt

Brian, I think you need a vacation.

Are you buying? [:D]

Hey Jim, if I'm pestering you just say the word and I'll drop it. If not I want to know why you think what you think. If it adds up I may need to adapt my own thinking; if not I'll hold what I've got.

Brian G.

The Mosquito [;)]

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