Terminating 350kcmil AL Compact Conductors

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curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
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Electrical Contractor
I?m going to be pulling a 200 amp feeder about 400? between 2 buildings. I was originally thinking of using 4/0 CU but now considering going with 350 AL. The line end will be a 225AF/200AT amp breaker located in a 400 amp panel board. The load end will be a 400AF/225AT enclosed breaker serving only as a service disconnect at the building being supplied.

The lugs on the breaker at the load end can easily handle the 350 AL conductors since it is a 400 amp frame breaker. The supply breakers lugs are rated for up to 300 kcmil.

The problem I have is my 350?s are technically too large for the 300 kcmil lugs. In reality since the aluminum conductors are compact conductors they are actually smaller in diameter that standard 300 kcmil conductors so would easily fit in the lugs.

I have 2 options.
(1) Install some Polaris connectors or = in the panel with a short section of smaller wire to connect to the breaker.

(2) Cheat and just terminate the 350?s directly on to the breaker since they will easily fit and I don?t see a real hazard.


I?m just curious to get the opinion of what others would do in this case. The first option is the only one that is really compliant but it is adding 2 additional connection points plus the additional cost.
 
are these existing breakers? what kind of lug options do you have?

have you considered pin adapters?
 
I would have no problem with (2)... but that's no assurance your AHJ/inspectorwill not have a problem with it. The way I see it, you can revert to (1) if necessary.

In the meantime, contact the breaker manufacturer and see if that upper range value is for standard stranding, and if 350 compact stranding is permitted under the listing. If yes, get their reply in writing, then copy and distribute as necessary for storing with permanent documentation.

350kcmil compact conductor diameter = 0.616"
300kcmil standard stranding diameter = 0.630"
 
Thanks for the replies so far.

The breaker is just a "cheap" GE TQD breaker already installed by my panel board manufacture. I'm sure there are no lug options available for these breakers.

Pin adapters are an option but I have always wondered about the listing of the pins with standard lugs since the lugs are not specifically listed for pins. In reality pins just reduce the size of the conductor so it will fit the lug. Since I'm proposing using compact conductors I feel I'm using 400' pin adapters. :)
 
Regarding the 350 kcmil Compact AL into the 300 kcmil rated lug....you would indeed ask the manufacturer of the lug and circuit breaker if applicable. Why...because I have asked them (we make the conductors) and they have told me (Thomas and Betts, in terms of LUGS) that the lug is designed in regards to the thickness of the lug, side walls of the lug and so on to accommodate the conductor size listed and expressed on the lug. Anything larger, be it concentric, compressed or compact would not be acceptable, they only test the lugs to the listings and sizes given, since a 350 kcmil compact technically could handle more ampacity than the 300 kcmil it is frowned upon. In other words, a lug with a maximum 300 kcmil could take concentric, compressed or compact up to 300 kcmil....and nothing larger even though it would technically fit.

When asked about the use for voltage drop considerings they said it would not matter in their eyes, they only consider the size listed and the evaluation that takes place on what could be placed (in terms of amps) on the conductor and lug.

Just some of my thoughts and two cents.....however every manufacturer of lugs are different so thats why I would reach out to them.
 
I would just connect the 350 compact AL into the 300 AL lugs and be done with it.
they fit and you are not loading above 200 amp so there won't be any problem.
 
curt swartz said:
...Pin adapters are an option but I have always wondered about the listing of the pins with standard lugs since the lugs are not specifically listed for pins. ...
Click to expand...
No worry with these: http://www.greaves-usa.com/pdf/Shoo-Pin Color Sheet.pdf

However, I'm uncertain if they are listed for compact AL conductors.

Here's a link to their adapter catalog: http://www.greaves-usa.com/pdfs/azone_cat.pdf

You might want to give them a call if this is the route you want to take.
 
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There is more to a UL Listed assembly (breaker and lug together) than simply 'does the conductor fit and is the amp rating adequate'.

Some of the other issues are: Wiring bending space in the listed enclosure and conductor pull out, especially during short circuits.
 
jim dungar said:
There is more to a UL Listed assembly (breaker and lug together) than simply 'does the conductor fit and is the amp rating adequate'.

Some of the other issues are: Wiring bending space in the listed enclosure and conductor pull out, especially during short circuits.
Click to expand...
THUS why we said to the OP...Call the manufacturer of the lug for clarification
 
MasterTheNEC said:
...Call the manufacturer of the lug for clarification
Click to expand...

As others have mentioned, it is the manufacturer of the assembly (e.g. the beaker) that needs to be contacted, although the lug manufacturer should be able to answer the pull out question.
 
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