wire pull question.

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cmreschke

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Here's the scenario: I ordered 4 cuts of 1/0 thhn compact aluminum and 1 cut #2 same for ground per specs on my prints. Run is 420' long 2" emt.
It is feeding a 100 amp mlo 208/120 3 phase with neutral panel from switch gear.
Boss sends out 1 cut 2/0 thhn al, 2 cuts 2/0 xhhw al, and 1 cut 1/0 xhhw al.
Question I have is I believe this to be a violation but have no book here to look it up I am sure you can't mix insulations like that correct?
Would you make the 1/0 your neutral as I think that's a violation as well correct?
Boss says pull it so pull it but how would you mark them?
 
You can mix insulation types (as long as they're not paralleled on the same phase or neutral) and the neutral must be sized for the connected load.
 
You could have had all aluminum conductors and one copper, as long as each one was properly sized for the ampacity required - no problem. Only thing is like Infinity mentioned if you have parallel conductors - the sets of each paralleled conductor must be identical in about every way you can think of - if they are not they will not necessarily carry equal amounts of current.
 
cmreschke said:
Here's the scenario: I ordered 4 cuts of 1/0 thhn compact aluminum and 1 cut #2 same for ground per specs on my prints. Run is 420' long 2" emt.
It is feeding a 100 amp mlo 208/120 3 phase with neutral panel from switch gear.
Boss sends out 1 cut 2/0 thhn al, 2 cuts 2/0 xhhw al, and 1 cut 1/0 xhhw al.
Question I have is I believe this to be a violation but have no book here to look it up I am sure you can't mix insulations like that correct?
Would you make the 1/0 your neutral as I think that's a violation as well correct?
Boss says pull it so pull it but how would you mark them?
Click to expand...

Does the customer know that the specs aren't going to be followed? There is more to this stuff than just the NEC.
 
K8MHZ said:
Does the customer know that the specs aren't going to be followed? There is more to this stuff than just the NEC.
Click to expand...

It seems like his boss did the right thing, upsizing the wire from 1/0 to 2/0 al, based on the length of the run.

(added) asuming a load of 80% on a 100amps you will have a 4.56% voltage drop at 420 feet with 2/0 al, his wire should actually be bigger.
 
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One note on the parallel conductors I mentioned, they only have to have the same characteristic per phase or neutral not all of the parallel conductors. You could have #3/0's on Phase A and 250 kcmil on phase B, etc.
 
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cmreschke said:
Here's the scenario: I ordered 4 cuts of 1/0 thhn compact aluminum and 1 cut #2 same for ground per specs on my prints. Run is 420' long 2" emt.
It is feeding a 100 amp mlo 208/120 3 phase with neutral panel from switch gear.
Boss sends out 1 cut 2/0 thhn al, 2 cuts 2/0 xhhw al, and 1 cut 1/0 xhhw al.
Question I have is I believe this to be a violation but have no book here to look it up I am sure you can't mix insulations like that correct?
Would you make the 1/0 your neutral as I think that's a violation as well correct?
Boss says pull it so pull it but how would you mark them?
Click to expand...

Is this in the same building or a separate structure? If a separate structure or in some cases a tenant's unit, you will need a main shut off at the panel.
 
cmreschke said:
Here's the scenario: I ordered 4 cuts of 1/0 thhn compact aluminum and 1 cut #2 same for ground per specs on my prints. Run is 420' long 2" emt.
It is feeding a 100 amp mlo 208/120 3 phase with neutral panel from switch gear.
Boss sends out 1 cut 2/0 thhn al, 2 cuts 2/0 xhhw al, and 1 cut 1/0 xhhw al.
Question I have is I believe this to be a violation but have no book here to look it up I am sure you can't mix insulations like that correct?
Would you make the 1/0 your neutral as I think that's a violation as well correct?
Boss says pull it so pull it but how would you mark them?
Click to expand...

It appears you were going to have an EGC (wire) thus 5 conductors. Your boss sent out only 4 conductors. Unless he is wanting to use the EMT as the EGC, you are one conductor short.
 
Same building not seperate.
He supplied a ground I just neglected to mention as it had no bearing on the o.p. he sent what I ordered in regards to the ground. Thanks for all the replies. I just questioned the different insulations, as I believed it to be a violation, one of those things I was taught when an apprentice but never bothered to challenge.
 
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