Aluminum wire on ground screw

[Under budget]

We have taken on a project to re terminate all wiring in a multi building apartment complex that was wired with aluminum wiring and wirenuts with alumicon purple connectors and copper pigtails to all devices . We are having disagreements amongst the crew as to the existing aluminum wire that is used to ground the metal boxes. Currently the metal boxes have an aluminum conductor from one of the aluminum romex cables wrapped around a machine screw extending to a wirenut with the other cables bare aluminum ground conductor. We are currently replacing this wirenut with an alumicon but leaving the bond connections to the metal box as is under a ground screw with the assumption that ground screws are not required to be listed . Looking forward to feedback from the Mike Holt Community

 

[infinity]

Ground screws are not required to be listed so you can use a machine screw for the purpose of connecting an EGC to a metal box. I would question whether or not it is permitted to wrap an aluminum conductor around a ground screw without an aluminum rated connector.

 

[ramsy]

I believe listed means is required for box bonding. There's more than 1 way to do this.

Since EGC wirenut is being replaced w/ Alumicon, why not add copper pigtail from Alumicon to Gnd screw.

 

[Under budget]

Ground screws are not required to be listed so you can use a machine screw for the purpose of connecting an EGC to a metal box. I would question whether or not it is permitted to wrap an aluminum conductor around a ground screw without an aluminum rated connector.

Ok is it permitted to wrap an aluminum conductor around a ground screw that is not required to be listed for aluminum wire?

 

[Under budget]

I believe listed means is required for box bonding. There's more than 1 way to do this.

Since EGC wirenut is being replaced w/ Alumicon, why not add copper pigtail from Alumicon to Gnd screw.

We are having issues with multiple wires in the box and the fact that alumicon doesn’t offer more than 3 port connectors , some boxes required to be fitted with several alumicons

 

[ramsy]

Yes, I see listing says 1-conductor per port.

In that case, there are other listed means for EGC wires, to accomplish the same thing.

 

[LarryFine]

Can (and may) you insert more than one wire per port?

Never mind. Just saw previous response after I started.

 

[Under budget]

Can (and may) you insert more than one wire per port?

Never mind. Just saw previous response after I started.

You understand the issue we are having requiring to daisy chain multiple alumicons together , and inserting multiple conductors into one port would prevent this but void its listing. By leaving the box bonding connection as is in some instances eliminates the requirement to daisy chain multiple 3 ports together thus more volume,cost,time etc. I just want to know how other professionals feel about this aluminum wire on the ground screw? Thanks for everyone’s time and input

 

[ramsy]

You should have posted a survey instead

 

[LarryFine]

I would have no qualms with using AlumiConn wirenuts on EGCs.

 

[synchro]

The lug with part number P2 on this page is approved for up to 4 aluminum wires of 14, 12, or 10 AWG (as long as each pair has the same gauge).
There's a hole for a #10 mounting screw or bolt. It's a little big at 1.21" x 0.56" x 0.46" but it still might work out better (and be cheaper) than using more AlumiConns for the grounds.

Buy Triple Wire Lugs (3 wires per lug, at LugsDirect.com

Buy triple wire triple barrel terminal lugs. Allow 800 kcmil to 14 AWG copper or aluminum wire, and are CSA certified and UL listed. Aluminum with tin plating. Made in the USA from domestic and imported parts

lugsdirect.com

 

[LarryFine]

You'd have to land the wires in the holes before securing it to the box, and then only if the threaded hole is near the center.

 

[synchro]

You'd have to land the wires in the holes before securing it to the box, and then only if the threaded hole is near the center.

Could tap another hole if necessary but that takes more messing around.

 

[oldsparky52]

Since there is no heating/cooling from current usage, the aluminum connected to the box should be just fine if it is fine when it is installed.

 

[infinity]

Ok is it permitted to wrap an aluminum conductor around a ground screw that is not required to be listed for aluminum wire?

That's the question, in my mind it seems like it would not be permitted but there would need to be a code section that prohibits it.

 

[kwired]

I believe listed means is required for box bonding. There's more than 1 way to do this.

Since EGC wirenut is being replaced w/ Alumicon, why not add copper pigtail from Alumicon to Gnd screw.

Nothing is listed (or required to be anyway) in a typical copper conductor and ground screw into the box application. Can even drill and tap new hole for the screw if you want in most circumstances.

 

[tortuga]

My understanding is copper and aluminum are the issue.
How likely is galvanic corrosion between aluminum and a seel alloy outlet box?
I am no metallurgist but I think steel and aluminum are mixed often on other construction assemblies.
I have even seen some old outlet boxes that are made of what I thought was aluminum with ground clips and copper wires attached.

 

[ramsy]

Nothing is listed (or required to be anyway) in a typical copper conductor and ground screw into the box application. Can even drill and tap new hole for the screw if you want in most circumstances.

See NEC 110.14

 

[ramsy]

My understanding is copper and aluminum are the issue.
How likely is galvanic corrosion between aluminum and a seel alloy outlet box?
I am no metallurgist but I think steel and aluminum are mixed often on other construction assemblies.
I have even seen some old outlet boxes that are made of what I thought was aluminum with ground clips and copper wires attached.

The code wants listing means for dissimilar metals, but mechanical strength may also be an issue w/ 15A Aluminum crushed under steel screws. Bend it a few times and it may snap right off.

 

[Clayton79]

You could use zinc plated machine screws, low galvanic corrosion.
Ideal ind. makes a green grounding screw that is zinc plated.

Doesn’t have to be green I know, just saying it is and that’s what they make.

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