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Double tap at main lug


elgato
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After not seeing this in a long time, I've seen it twice in a week. At my last inspection, the homeowner argued with my position that this was improper. He said his buddy, an electrician, wired the feed for his garage into the main lugs, and it was "OK" because there was a main switch upstream from the distribution panel that I was looking at. I asked to see the switch. It was at the other end of the basement, behind paneling. It was a main on/off switch with a 200amp breaker. I told him I still felt it was improper, and recommended evaluation by a licensed electrician. This type of connection is always improper, correct??

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"I told him I still felt it was improper, and recommended evaluation by a licensed electrician."

The simple fact is that, between this and the garage panel, the #8(?) wires are only "protected" by the 200-amp disconnect. Also, of course, those terminals aren't rated for the double tap...even if it was somehow, otherwise OK. It doesn't need evaluation. It needs repair!

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Originally posted by elgato

After not seeing this in a long time, I've seen it twice in a week. At my last inspection, the homeowner argued with my position that this was improper. He said his buddy, an electrician, wired the feed for his garage into the main lugs, and it was "OK" because there was a main switch upstream from the distribution panel that I was looking at. I asked to see the switch. It was at the other end of the basement, behind paneling. It was a main on/off switch with a 200amp breaker. I told him I still felt it was improper, and recommended evaluation by a licensed electrician. This type of connection is always improper, correct??

Yes. This type of connection is always wrong.

That breaker isn't labeled to accept more than one wire per lug. That alone makes it wrong.

Of course, the skinny wire lacks adequate overcurrent protection and this situation doesn't support one of the tap rules. So it's wrong for that reason too.

Lastly, is that copper and aluminum under the same lug? If so, it's wrong for that reason as well.

- Jim Katen, Oregon

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Originally posted by AHI

I thought I had heard somewhere that the one situation where tapping in an extra wire to the main lug is when it is part of wiring for a lightning arrestor system. Can anyone confirm if this is correct?

It isn't correct unless the lug it labeled for that use.

Get ahold of some lightning arrestor installation instructions. What do they say?

You'll also see this done on older commercial buildings where the emergency lighting system is tapped off the main lugs before the main breaker. The logic was that, in the case of a fire, you could shut the main breaker and still have your emergency lights work. Batteries did away with this improper practice some time ago.

- Jim Katen, Oregon

- Jim Katen, Oregon

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Originally posted by AHI

I thought I had heard somewhere that the one situation where tapping in an extra wire to the main lug is when it is part of wiring for a lightning arrestor system. Can anyone confirm if this is correct?

We discussed that topic here within the past year or two. One member contacted the top manufacturer of lightning arrestors. They said it was wrong. It should be installed on an additional 2-pole breaker. Another member posted a graphic of how it should be installed:

delta-instal.jpg

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