200 amp feeder cable for residential.

Status
Not open for further replies.
R

rhovee

Member
So I have heard about people being called on using 4/0 SER for a 200 amp panel since SER is rated in the 60 degree column and therefor is only good for 150 amps. Just seeing what type of cable people have been using for 200 amp services. I am setting a 320 meter with (2) 200 amp breakers, then running it into the house. In Washington, we are limited to 15 feet of SEC inside the building.
 
The answer is a bit elusive depending on Code cycle and can vary by jurisdiction.
You OP confuses me (not a difficult thing to do). Do you have overcurrent protection at the meter ?
(only slightly related but the 15ft limit threw me).

Since you have two cables most jurisdiction would have the opinion that 310.15(B)(6) did not apply, as flatlander notes above, so you would be limited to the 310.16 ampacities. That ampacity will vary depending on the Code cycle and if the cable is installed in insulation.
 
augie47 said:
The answer is a bit elusive depending on Code cycle and can vary by jurisdiction.
You OP confuses me (not a difficult thing to do). Do you have overcurrent protection at the meter ?
(only slightly related but the 15ft limit threw me).

Since you have two cables most jurisdiction would have the opinion that 310.15(B)(6) did not apply, as flatlander notes above, so you would be limited to the 310.16 ampacities. That ampacity will vary depending on the Code cycle and if the cable is installed in insulation.
Click to expand...

Long story short, inspectors are calling 4/0 SER 60 degree column and making us put on 150 amp beaker. Just seeing what others have done short of piping and pulling wire.
 
Depending on which Code cycle you are under and the specifics of the installation, the inspectors call may well be valid. Once the 60° SE limitation entered the Code a lot of the E/Cs in this areas went to conduit.
 
And to clear things up from my OP, what we have to do in Washington is set the 320 meter and offset nipple out each side to a 200 amp disconnect. Than I used to run 4/0 SER directly to a 200 amp panel. But recently the local AHJ has called me on 60 degree and says they need to be 150 amp breaker because of 60 degree column. And we are on the 2014
 
rhovee said:
And to clear things up from my OP, what we have to do in Washington is set the 320 meter and offset nipple out each side to a 200 amp disconnect. Than I used to run 4/0 SER directly to a 200 amp panel. But recently the local AHJ has called me on 60 degree and says they need to be 150 amp breaker because of 60 degree column. And we are on the 2014
Click to expand...

I believe what the inspectors are citing is that having 2 feeders to 2 separate panels coming from the 320 amp meter pan does not meet the requirements as specified in 310.15(B)(7)(2) and therefore you must size the feeder in accordance with Table 310.15(B)(16). If the SER cable is installed in thermal insulation 338.10(B)(4)(a) requires that you use the 60 degree column of 310.15(B)(16) for the ampacity of the feeder conductors.

Chris
 
victor.cherkashi said:
NEC 2008 permits you to do 4/0 for 200A aluminum. New one, No

Sent from my Nexus 5 using Tapatalk
Click to expand...

depends on a lot of factors. Load, service or main feeder, and conductor or cable type.
338.10 throws a wrench in the deal when SE is involved.
 
raider1 said:
I believe what the inspectors are citing is that having 2 feeders to 2 separate panels coming from the 320 amp meter pan does not meet the requirements as specified in 310.15(B)(7)(2) and therefore you must size the feeder in accordance with Table 310.15(B)(16). If the SER cable is installed in thermal insulation 338.10(B)(4)(a) requires that you use the 60 degree column of 310.15(B)(16) for the ampacity of the feeder conductors.

Chris
Click to expand...
That is exactly what I am seeing. If supplying two separate panels and neither is carrying the entire load of a dwelling unit, they must be 200 amp conductors (or whatever allows next size up of 200 as long as load doesn't exceed actual conductor ampacity).

But same 4/0 can be in parallel to a 400 amp switch/panel and are going to be suitable for 400 amps, as long as that is supplying the entire dwelling unit load.
 
raider1 said:
No, I believe the question is in regards to the 2 feeders from the service to the 2 200 amp panels

Chris
Click to expand...
:thumbsup:Which, as stated, means neither of them carries the full occupancy load and so special treatment which would apply to service conductors does not apply.
 
Status
Not open for further replies.
Top