Table 310.15(B)(6) Service conductors Dwelling

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Sierrasparky

Sierrasparky

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USA
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Electrician ,contractor
Hey,
Was wondering. Will a dwelling feeder #4-3 w/10g romex be compliant at 100 amp rating if all the load is through this feeder?
I want to use cable and all the supply house in my area has for available for cuttng is #4-3 Romex. They do not have any
USE or SE cable.
 
Oh I forgot This is after the Main breaker, But will feed the entire dwelling. It will be fed through the wall.
 
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George is stating that you need #1 NM because of using the 60 deg. column of the ampacity table which gives you 110 amps or

#2 at 95 amp. I would argue that you could go to the next higher breaker 100a. I could be wrong!


I would also want to know about not required to exceed the size of the service entrance wires. What I don't necessasrily understand is for feeders you must only use the wire types in the table.
 
Sierrasparky said:
#2 at 95 amp. I would argue that you could go to the next higher breaker 100a. I could be wrong!
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If the load is less than 95 amps, you up size this breaker 240.4(B)


I would also want to know about not required to exceed the size of the service entrance wires
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It says ampacity not size.


. What I don't necessasrily understand is for feeders you must only use the wire types in the table.
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Because I said so. J/k:), I think I may know this but at 2:30AM ,I give up
 
jumper said:
If the load is less than 95 amps, you up size this breaker 240.4(B)




It says ampacity not size. You are correct!, and # 1 would be greater!




Because I said so. J/k:), I think I may know this but at 2:30AM ,I give up
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Yep it's late
 
The values in 2008 310.15(B)(6) are an average of 12% under the 75 degree equivalents in 310.16. Since they despise NM anyway, they sure don't want it to take advantage of this table.
 
George Stolz said:
NM is no good, you'd need #1 NM or #2 AL SE-R.
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Sierrasparky said:
George is stating that you need #1 NM because of using the 60 deg. column of the ampacity table which gives you 110 amps or
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iwire said:
You cannot use Table 310.15(B)(6) for NM, if you want to use NM you have to use Table 310.16.
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I understand about not using Table 310.15)B)(6), what I didn't understand was George's statement "NM is no good", then said use NM. That is what confused me.
 
The #4 would be good for 100A (assuming it's copper), but the #10 ground is not. 100A requires #8 Ground.
That would be first thing besides other restrictions on rommex.

Sierrasparky said:
Hey,
Was wondering. Will a dwelling feeder #4-3 w/10g romex be compliant at 100 amp rating if all the load is through this feeder?
I want to use cable and all the supply house in my area has for available for cuttng is #4-3 Romex. They do not have any
USE or SE cable.
Click to expand...
 
Strife said:
The #4 would be good for 100A (assuming it's copper), but the #10 ground is not. 100A requires #8 Ground.
That would be first thing besides other restrictions on rommex.
Click to expand...
#4is only good for 100 amps when using Table 310.15(B)(6) or (B)(7) in the 2011. That table does not allow nm cable. I believe the reason is that at one time SE cable was rated 75C and all other cables and conductors in that table were rated 75C. I will be curious if they revise this table since se cable is often rated 60C.
 
Dennis Alwon said:
I will be curious if they revise this table since se cable is often rated 60C.
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Do you have anything to back that up?

UL White Book said:
Type SE — Indicates cable for aboveground installation. Both the individual insulated conductors and the outer jacket or finish of Type SE are suitable for use where exposed to sun. Type SE cable contains Type RHW, RHW-2, XHHW, XHHW-2, THWN or THWN-2 conductors. Maximum size is 4/0 AWG copper or 300 kcmil aluminum or copper-clad aluminum.

Types USE and USE-2 — Indicates cable for underground installation including direct burial in the earth. Maximum size is 2000 kcmil. Cable in sizes 4/0 AWG copper, aluminum or copper-clad aluminum and smaller and having all conductors insulated is suitable for all of the underground uses for which Type UF cable is permitted by the NEC. Multiconductor Type USE cable contains conductors with insulation equivalent to RHW or XHHW. Multiconductor Type USE-2 contains insulation equivalent to RHW-2 or XHHW-2 and is rated 90?C wet or dry. Single- and multiconductor Types USE and USE-2 are not suitable for use in premises. Single and multiconductor Types USE and USE-2 are not suitable aboveground except to terminate at the service equipment or metering equipment. Both the insulation and the outer covering, when used, on single- and multiconductor Types USE and USE-2, are suitable for use where exposed to sun.
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Looks like they use all conductors rated for 75?.
 
George Stolz said:
Do you have anything to back that up?
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We were taking about a sub panel that carries the load of the service-- I thought. To use T. 310.16(B)(7) NM would not be allowed however ser is allowed even though it is rated 60C or in 2011 it is rated 60C when run thru insulation.
 
Well thanks for the great info I tried to pass it along. I contacted the supply house and they are baffled. They told me that they carry #2 CU and that good for dwelling service, feeders ect. at 100 amps. I told the owner it won't work code does not allow it. He tells me they don't stock the SE stuff as we only stock Copper wire no Aluminum. I said you can get the stuff in copper too. He's going to continue with the same. I guess I am out of luck unless I want a big roll. That is what I get for wanting to use copper.


I had a some #2 AL SE cable out back so I used it.
 
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