# of Grounds under one screw

[KWH]

The disconnects I installed did not come with a grounding lug or bar. I tapped and threaded a s.p.a ( butt splice ) to the box and have 3 #12 ground wires under one screw, inspector says not rated for more than one wire, how many grounds the same size can you terminate under one screw in a panel or service disconnect. This does not sound right.

 

[iwire]

I tapped and threaded a s.p.a ( butt splice ) to the box

Plus one for creativity, minus two for a violation of 110.3(B). You did not use the SPA as t is listed and labeled.

110.3 Examination, Identification, Installation, and Use
of Equipment.

(B) Installation and Use. Listed or labeled equipment
shall be installed and used in accordance with any instructions
included in the listing or labeling.

and have 3 #12 ground wires under one screw,

I assume you mean you stuck 3 #12s into one end of the SPA and tightened the set screw?

If so that is also a 110.3(B) violation but even more specifically 110.14(A)

110.14 Electrical Connections.


(A) Terminals. Connection of conductors to terminal parts
shall ensure a thoroughly good connection without damaging
the conductors and shall be made by means of pressure connectors
(including set-screw type), solder lugs, or splices to
flexible leads. Connection by means of wire-binding screws or
studs and nuts that have upturned lugs or the equivalent shall
be permitted for 10 AWG or smaller conductors.

Terminals for more than one conductor and terminals
used to connect aluminum shall be so identified.

That means the SPA would have to be marked that is could accept 3 #12s or it is a violation. I use SPAs and I don't recall any that are listed for more than one conductor per end.

 

[KWH]

Thanks I wire is a ground bar

Thanks I wire is a ground bar

Is a ground bar in a panel listed, I have always put 2 or 3 grounds under one screw but never actually took the time to read the label.

Thanks for the quick reply

 

[iwire]

Is a ground bar in a panel listed, I have always put 2 or 3 grounds under one screw but never actually took the time to read the label.

You bet, but many of those allow two or three conductors in each hole, they are listed for that use.

But SPAs no, not so much

Thanks for the quick reply

No problem but heading to work now.

 

[infinity]

What's an SPA? The OP mentions an SPA and a butt splice, how can they be the same thing?

 

[charlie b]

What's an SPA?

I did a quick search, and did not find the meaning of "s.p.a." But I did find this example:
http://www.munroelectric.com/catalog/ilsco/sleeves.html

 

[jumper]

I did a quick search, and did not find the meaning of "s.p.a." But I did find this example:
http://www.munroelectric.com/catalog/ilsco/sleeves.html

Thanks. I was curious also. As, Iwire said, that is creative to bolt it to a panel, although wrong.

 

[marti smith]

Nearly every single item one can install comes with paperwork of some sort. Many ground bars allow for two grounding conductors under a screw, but not a grounded conductor- usually only allow one under per terminal. Check out your installation instructions. It may not allow what you want, but you'll be better informed, and it'a good habit to acquire!

 

[iwire]

I did a quick search, and did not find the meaning of "s.p.a." But I did find this example:
http://www.munroelectric.com/catalog/ilsco/sleeves.html

That is the item.

I think SPA stands for Splicer, Reducer, Aluminum.

 

[Twoskinsoneman]

Thanks. I was curious also. As, Iwire said, that is creative to bolt it to a panel, although wrong.

+1 for that I didn't know the SPA either.

 

[suemarkp]

Did your panel come with a 10-32 hole for grounding, you were just short terminals or screws? If so, the Cutler Hammer grounding bars are designed to mount in 10-32 holes. I use the little GBK5 5 hole ones when I need to deal with a bunch of grounds in a box. It would be nice if they made even smaller ones, since they are listed for up to 3 wires per terminal if the wires are the same size and material. This approach also works well when you have a bunch of grounds all sized differently or have oversized them, since you can't share terminals in that case.

 

[Ponchik]

on a second note, why not use a small ground bar that has multiple screws on it?

 

[buddhakii]

In a pinch just zip in three ground screws. The self tappers work great. Just drill a hole with a tek screw and the self tapping grnd. screw will thread in perfectly.