2/0 copper amperage

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bth0mas20

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Maryland
I dont get these jobs often enough to keep up with the codes. I got a call today to replace 150' of 4/0 copper wire from a meter to the 200amp panel in a resturant.
Its 3 phase and the inspector said that the 4/0 needs to be removed and 2/0 pulled in place of it. I looked in the code book and saw that 2/0 copper is good for 195 amps 90 deg C. With the run being 150' and its only good for 195 amps is this allowed? I cant replace the pipe because its already in the floor.
 
augie47

augie47

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sounds like a misunderstanding. I would run it by your inspector again.
Under normal conditions a 2/0 cu in this situation would be good for 175 amps maximum.
 
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hurk27

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Location
Portage, Indiana NEC: 2008
If you cant use 3/0 then the main will have to be lowered, What size is the conduit? and since they ran 4/0 was this because of voltage drop?, Is the conduit RMC , EMT, or PVC?
310.16(B)(6) can only be used for dwellings, maybe this inspector is thinking it can be used for this restaurant?
 
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Cow

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Eastern Oregon
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Electrician
bth0mas20 said:
I dont get these jobs often enough to keep up with the codes. I got a call today to replace 150' of 4/0 copper wire from a meter to the 200amp panel in a resturant.
Its 3 phase and the inspector said that the 4/0 needs to be removed and 2/0 pulled in place of it. I looked in the code book and saw that 2/0 copper is good for 195 amps 90 deg C. With the run being 150' and its only good for 195 amps is this allowed? I cant replace the pipe because its already in the floor.
Click to expand...

They ran 150' from the meter into the restaurant? That seems awfully long.....
 
infinity

infinity

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More information is needed.

-What size and type of conduit?
-What size is the OCPD and is it located at the panel?
-The 150' of conduit is completely encased in concrete or run outside of the building?
 
Dennis Alwon

Dennis Alwon

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Chapel Hill, NC
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I am very confused. You said the inspector wants you to remove 4/0 copper and install 2/0 copper???? Why. I could understand if he said remove the 2/0 and use 4/0.
 
Dennis Alwon

Dennis Alwon

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Chapel Hill, NC
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1793 said:
If it is a 200A OCPD then the 2/0 copper would be too small.

Why 2/0 is a great question.
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I know that, Why does the inspector not realize bigger is fine. I guess in his mind bigger isn't better. :grin:

He is think resi work where 2/0 is fine based on T310.15(B)(6)
 
cowboyjwc

cowboyjwc

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Simi Valley, CA
Because you can't run 3 4/0 and a ground in a 2" conduit. Plus it's only 200 amps anyway, but I do agree that he would need at least 3/0.
 
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Dennis Alwon

Dennis Alwon

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cowboyjwc said:
Well we may disagree here simply on the bases of geography. Here you are required to have a main service disconnet at the meter, which would make everything after that a feeder.
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I agree with that but the op said from meter to panel so..... Who knows?:)
 
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bth0mas20

Senior Member
Location
Maryland
I only know what the owner is telling me so far. Im going to look at this job tonight to understand beter whats going on. Ill know more later.
 
infinity

infinity

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New Jersey
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bth0mas20 said:
I only know what the owner is telling me so far. Im going to look at this job tonight to understand beter whats going on. Ill know more later.
Click to expand...


If we give the inspector the benefit of the doubt then something has been lost in translation.
 
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