ser cable

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electric291

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Can you still use type SER cable for sub panels in dwellings sized at #2 aluminum for 100 amp and 4/0 aluminum for 200 amp. I had an inspector tell me you can no longer do this because the insulation is only 60 degrees. I thought it was ok per table 310.15 (B) (6).
 
IMO if you had to choose one answer it would be no. You'll need to use the 60 degree column of 310.16. As Augie mentioned there are exceptions.
 
electric291 said:
Can you still use type SER cable for sub panels in dwellings sized at #2 aluminum for 100 amp and 4/0 aluminum for 200 amp. I had an inspector tell me you can no longer do this because the insulation is only 60 degrees. I thought it was ok per table 310.15 (B) (6).
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a lot of people do it, but there is a new sentence in 2008 code that makes a clarification between main panels and subpanels. the only time you can use the 310.15 chart for subs is when you have a meter disconect.
 
iand74 said:
a lot of people do it, but there is a new sentence in 2008 code that makes a clarification between main panels and subpanels. the only time you can use the 310.15 chart for subs is when you have a meter disconect.
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I am not sure I understand you but I think you are saying that it is okay to use 310.15(B)(6) if the SER carries the entire load of the service. Just clarifying.
 
Dennis Alwon said:
I am not sure I understand you but I think you are saying that it is okay to use 310.15(B)(6) if the SER carries the entire load of the service. Just clarifying.
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Dennis,in a CEU class I was in with all the Wake Co. inspectors this came up. They were of the mind set that if you have a 200amp back to back service then (B)(6) applies, if you have a 200amp meter combo with feed though lugs to a single panel it would still fall under (B)(6). There reasoning was even though you may install breakers in the combo to feed an A/C unit that service is carrying the total load.
 
ceb58 said:
There reasoning was even though you may install breakers in the combo to feed an A/C unit that service is carrying the total load.
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Another reason is that any load supplied by the combo is a load not placed on the feeder.
 
ceb58 said:
Dennis,in a CEU class I was in with all the Wake Co. inspectors this came up. They were of the mind set that if you have a 200amp back to back service then (B)(6) applies, if you have a 200amp meter combo with feed though lugs to a single panel it would still fall under (B)(6). There reasoning was even though you may install breakers in the combo to feed an A/C unit that service is carrying the total load.
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Well a back to back service is different. Are we talking conduit or ser or seu. Certainly a meter outside to a panel directly inside would meet the requirements of (B)(6) whether or not se cable was used. Our state inspector Ron Chilton would definitely argue with those Wake Co. guys on the other issue. The NEC plainly and simply does not allow it. There was some talk at the state meeting that there was some discussion about allowing an a/c and/or a detached garage to be fed from the main panel without losing the (B)(6) ruling to a sub panel. That is not the code at this point.
 
Dennis Alwon said:
Well a back to back service is different. Are we talking conduit or ser or seu. Certainly a meter outside to a panel directly inside would meet the requirements of (B)(6) whether or not se cable was used. Our state inspector Ron Chilton would definitely argue with those Wake Co. guys on the other issue. The NEC plainly and simply does not allow it. There was some talk at the state meeting that there was some discussion about allowing an a/c and/or a detached garage to be fed from the main panel without losing the (B)(6) ruling to a sub panel. That is not the code at this point.
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And the discussion they had with Mr. Chilton also came up. A meeting of the minds that resembled a head on collision. The way I read (B)(6) is " all loads that are part or associated with the dwelling unit". To me it defines the application as the main feeder to the panel board. Let me ask this, If because of lay out, you had to set a 200amp meter/combo and run 30' of ser. What size ser would you use.
 
Especially in residential work. All service/sub-feed conductors are installed in PVC conduit. :wink:

We don't use no stinkin' SER

Besides, you can't use that junk when feeding a mobile home anyhow.
 
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kbsparky said:
Especially in residential work. All service/sub-feed conductors are installed in PVC conduit. :wink:

We don't use no stinkin' SER

Besides, you can't use that junk when feeding a mobile home anyhow.
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kbsparky,
Is disallowed use of SER a local call or CA code for interior feeds? (I.e. Range feed and meter center tenant disconnect to multi-unit panels) rbj
 
I don't use SE cable either. I use PVC and copper conductors. Most of my customers don't want aluminum so it is an easy sell. Personally I like working with copper and at 3/0 or 2/0 the wire size is very manageable.
 
ceb58 said:
Let me ask this, If because of lay out, you had to set a 200amp meter/combo and run 30' of ser. What size ser would you use.
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That can be answered 2 ways. If their is no other loads in the exterior meter combo then 4/0 SER AL will suffice. Now, as I see it but don't agree with it, the code would require 300 MCM SER AL if their was another load in the meter combo. Now the SER does not serve the entire load of the dwelling-- ridiculous ? Yes, but that is the official ruling from Ron and my understanding of the 2008 NEC.
 
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