600 KCMIL wires

[lady sparks lover]

I used to be in favor of using only up to 500 KCMIL wires, but now my supervisor tells me he's heard from some of the contractors that they like to use 600Kcmil wires instead.

It's a dispute between the older man who's experienced and my supervisor the department head and an ex-contractor about going past 500KCMIL size wires and using the 600KCMIL wires.

what's your take on this?? What do you prefer??

 

[don_resqcapt19]

Re: 600 KCMIL wires

Lady,
I think that in most cases you will find that a set of smaller conductors in parallel is cheaper and easier to work with than 600 kcmil.
Don

 

[roger willis]

Re: 600 KCMIL wires

I'm with you Don, I always paralleled over 500. So much easier to work with.

Roger

 

[ed downey]

Re: 600 KCMIL wires

Lady,
I Agree That 500 MCM Conductors Are As Large As You Should Go Except In Special Circumstances. One Of The Local Utilities In This Area Also Requires That You Pull Nothing Larger Than 500 MCM To The Secondary Side Of The Utility Transformer.

 

[ryan_618]

Re: 600 KCMIL wires

I agree with what everyone is saying so far with one difference... as per 240.4(C) once you are over 800 amps 500's are no longer good for 400 anmps each. With that in mind I would say that a 1200 amp service would PROBABLY be cheaper and easier with (3) parrelled 600's.

 

[gregoryelectricinc]

Re: 600 KCMIL wires

500 MCM is as large as I will go before paralelling. I used 600 MCM 1 time amd 1 time only. The local utility then drilled out the 500
MCM rated lugs in their transformer while I watched because they did not have any larger lugs to install. THAT was the ONLY time I wanted to witness that particular act.

 

[tom baker]

Re: 600 KCMIL wires

I had a 400 amp pump station with the service entrance conductors at 750 MCM. The power company only had 500 MCM lugs, so they trimmed off the extra strands on the 750 to make it fit. After about ten years the lugs overheated, melted, and dripped down onto the roof.
If the power company had lugs for 600 it would OK. Actually on the larger sizes, 4/0 and up, I prefer alluminum, due to reduced ampacity its a natural to run it in parallel.

 

[pierre]

Re: 600 KCMIL wires

Tom

Could you clarify the last sentence of you last post? Thanks

Pierre