SER Cable

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moresi

Member
Well since the '08 code change now requiring us to use the 60 degree column for SE / SE style R cable I have an excess number of #2 SER spools in my shop. Bought them a few years back on a closeout to use primarily for 100 amp residential subpanels. So what are all you resi. guys using now for your 100 amp sub panels? Copper / Romex or 1/0 SER?
 

jwjrw

Senior Member
Well since the '08 code change now requiring us to use the 60 degree column for SE / SE style R cable I have an excess number of #2 SER spools in my shop. Bought them a few years back on a closeout to use primarily for 100 amp residential subpanels. So what are all you resi. guys using now for your 100 amp sub panels? Copper / Romex or 1/0 SER?

Im keeping the #2 and fusing it at 90amps.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
we'll see... last draft I saw they simply changed it to "60? when in insulation"
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I didn't say they made it less controversial :grin:

Where installed in thermal insulation, the ampacity shall be
in accordance with the 60?C (140?F) conductor temperature
rating. The 90?C (194?F) rating shall be permitted to be
used for ampacity adjustment and correction purposes, provided
the final derated ampacity does not exceed that for a
60?C (140?F) rated conductor.
[ROP 7-133]
 

jwjrw

Senior Member
I didn't say they made it less controversial :grin:

Where installed in thermal insulation, the ampacity shall be
in accordance with the 60?C (140?F) conductor temperature
rating. The 90?C (194?F) rating shall be permitted to be
used for ampacity adjustment and correction purposes, provided
the final derated ampacity does not exceed that for a
60?C (140?F) rated conductor.
[ROP 7-133]


Yea it would be too easy to say" if ran inside blah you must" blah 60deg column.
Then again if my girlfriend said what she really "meant" then life wouldnt be any fun!:D
 

nakulak

Senior Member
Yea it would be too easy to say" if ran inside blah you must" blah 60deg column.
Then again if my girlfriend said what she really "meant" then life wouldnt be any fun!:D

In a world with rampant and hideously poor comparisons, that, sir, is a truly superior analogy.
 

jwjrw

Senior Member
Assuming aluminum, you're going to need to fuse that 75 amp load and wire no larger than 80 amps.
240.4(B) > 240.6
T310.16

Well when your wrong you are wrong.....I was thinking ampacity at 60 was higher.
Depends on the situation I guess....
 

raider1

Senior Member
Staff member
Location
Logan, Utah
Well since the '08 code change now requiring us to use the 60 degree column for SE / SE style R cable I have an excess number of #2 SER spools in my shop. Bought them a few years back on a closeout to use primarily for 100 amp residential subpanels. So what are all you resi. guys using now for your 100 amp sub panels? Copper / Romex or 1/0 SER?

If the calculated load of the "sub-panel" is less than 80 amps, I would still use the #2 SER and just install an 80 amp breaker.

Chris
 

Dennis Alwon

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Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Well when your wrong you are wrong.....I was thinking ampacity at 60 was higher.
Depends on the situation I guess....
When would 60C be rated higher than 90C? The wire itself is rated for the amperage at 90C or more but the insulation is the weak link. Just look at the difference in #8 wire at 90C in T. 310.16 and then look at the same wire in T. 310.17 for free air. Same size wire can hold alot more amps. The insulation is what breaks down.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
If the calculated load of the "sub-panel" is less than 80 amps, I would still use the #2 SER and just install an 80 amp breaker.

Chris
Yet if it is SEU cable as service conductors that same wire in insulation can be used for 100 amps, :-? IMO. I know Gus and I disagree on this one.
 

jwjrw

Senior Member
When would 60C be rated higher than 90C? The wire itself is rated for the amperage at 90C or more but the insulation is the weak link. Just look at the difference in #8 wire at 90C in T. 310.16 and then look at the same wire in T. 310.17 for free air. Same size wire can hold alot more amps. The insulation is what breaks down.

Once again I didnt express myself well. I was thinking(not looking) that the #2 had an ampacity of 90amps at 60 deg. But its 90amps at :D75 deg.
I even said I was wrong..... Happens to all of us on here.... some more than others.
 

jwjrw

Senior Member
I know it was the part that stated it that made me make my statement.

I wasn't picking just trying to clarify.

Yea I meant depending on the situation I may run pvc, or a bigger wire or fuse it at 80...
Like I said I dont express myself well and you guys do have exerience in areas I have some but not alot of in...
I learn alot and appreciate you questioning me thanks Dennis.:D
 
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