# Multiple wire in a lug



## electrocutie (Oct 2, 2014)

Can 2 wires 4/0 be screwed into a single lug? 

Specs:
400 amp distribution panel meter base residential service.
Lug text, 2\250MCM-1/0 and 600MCM-4 CU9AL
2 alum. wires 
Wires going to two different 200 amp breaker panels

My take on this is; 4/0(212 kcmil) is less than 250 so the size is valid for 2 conductors 4/0. The doubled up wire size can be between 2 ea. 1/0 and 250MCM. The maximum single wire size is between #4 and 600MCM
Also; CU9AL will allow copper/aluminum
Bolted to the bus bar from the Mfg.

Can't post a pic yet. 

Can the inspector reject this for some reason besides having a bad day?

Thanks


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## Black Dog (Oct 16, 2011)

electrocutie said:


> Can 2 wires 4/0 be screwed into a single lug?
> 
> Specs:
> 400 amp distribution panel meter base residential service.
> ...


Single lugs are not rated for two conductors.

Welcome to the forum.:thumbsup:


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## Crack Wireman (Aug 22, 2014)

You're talking about a class 320 meter base. They don't come with twin lugs, you have to order 3 sets of the twins and bolt them to the bus. 1/2" socket I believe.


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## Crack Wireman (Aug 22, 2014)

Like that


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## Crack Wireman (Aug 22, 2014)

Pic came out crooked and I don't know how to rotate it. But there's twin lugs on the load side


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## Roger (Jul 7, 2007)

Black Dog said:


> Single lugs are not rated for two conductors.
> 
> Welcome to the forum.:thumbsup:


Harry, that is not true, many single lugs are listed for (2) conductors and the lug she describes will accept (2) 4/0 conductors

Roger


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## Black Dog (Oct 16, 2011)

electrocutie said:


> Can 2 wires 4/0 be screwed into a single lug?
> 
> *Specs:
> 400 amp distribution panel meter base residential service.
> ...





Roger said:


> Harry, that is not true, many single lugs are listed for (2) conductors and the lug she describes will accept (2) 4/0 conductors
> 
> Roger


Thanks Roger, not sure how I missed the specs posted.:thumbsup:


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## Southeast Power (Jan 18, 2009)

electrocutie said:


> Can 2 wires 4/0 be screwed into a single lug?
> 
> Specs:
> 400 amp distribution panel meter base residential service.
> ...


Yes, the 2/ indicates that you can terminate two conductors, 250 - 1/0 or a single conductor as large as 600 all the way down to a #4 so, your assumptions are correct.
Is someone challenging you on this or are you using this for a specific application?


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## electrocutie (Oct 2, 2014)

No challange on this. There's just so much talk about only one wire per lug. I was sure about this from the spec. but I wanted to get it in print on the web so folks see the specs. Half the people I spoke with said "you need a dual lug". Thanks.


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## dronai (Apr 11, 2011)

I didn't know that "Cutie" :laughing:


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## ElectricJoeNJ (Feb 24, 2011)

IiRC the lugs that will accept 2 wires are shaped differently than a standard single lug. Almost look tear drop shaped.


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## Carultch (May 14, 2013)

electrocutie said:


> Can 2 wires 4/0 be screwed into a single lug?
> 
> Specs:
> 400 amp distribution panel meter base residential service.
> ...


By default, lugs are only rated for one wire, unless listed and marked otherwise. You aren't permitted to just "add up the KCMIL" or "add up the metal diameters", to fit two wires in to a lug that is only rated for one large wire.

It sounds like you DO have a lug that is listed and marked otherwise for two wires, which permits you to do exactly this. A lot of lugs that meet this criteria have an opening that is shaped like a snowman, such that the lug could fit one large wire in its "body" or two small wires (one in its "head" and one in its "body").

You are permitted to use listed dual wire lugs, for whatever purpose you may need. Whether it be connecting two parallel sets of wires for the same circuit, or whether it be connecting two separate circuits from the same piece of equipment.

If doing the latter, make sure you pay attention to your tap rules. Suppose you have a circuit that is protected by a master 400A breaker, and then fed to two 200A MCB panels downstream. If you do not have 400A of wiring to each of the panels, then that division of the circuit is not a feeder, but a tap. It is a portion of a circuit that isn't sufficiently sized for the upstream means of protection.

It is OK to have two 200A circuits with 200A of wiring, fed from a 400A master breaker. As long as you pay attention to the specific rules apply, in the 240.21 section of the NEC. 10 ft tap, 25 ft tap, outdoor unlimited tap, and the very obscure 100 ft tap rule.


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