philsoma
Member
- Location
- Brighton, Michigan
I was referring to the idea that the load should be no more than 80% of the cb rating.
5 of the
6/2 CU cable: 60amp cb?
- Thread starter philsoma
- Start date
5 of the
philsoma
Member
- Location
- Brighton, Michigan
You guys convinced me. I will go with the 50-amp setting on the EV charger, using 40amps.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Even if you went with the 48 amps setting #6 NM cable is not going to burn up. Code compliant no, real world compliant yes.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
I used to get “ I have never heard of that”
When I knew what it was I needed
kwired
Electron manager
- Location
- NE Nebraska
210.19(A) says minimum conductor ampacity is to be 100% of non continuous load plus 125% of continuous load. If you have 60C insulation then 125% of 48 amps is 60. A 6 AWG 60C conductor only has an ampacity of 55, you must use a larger conductor. If it were a non continuous load then the 6 AWG @ 60C would be ok.
General overcurrent protection rules are basically about the same thing. 100% non continuous plut 125% of continuous.
kwired
Electron manager
- Location
- NE Nebraska
Technically there is only a 125% rule. But if working things backward then 80 is the reciprocal of 125.
So a 60 amp breaker that has a continuous load on it can only have that load be 60 x .80 = 48 amps.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Yes, that rule makes no sense, and should be deleted. 210.20, shown in post #24, suffices to avoid nuisance tripping of non-100% rated OCPD under continuous loads. And then 240.4 will give you the minimum ampacity of the conductor to be protected by the OCPD sized to 210.20.
Where the 210.20 OCPD is over 800A, deleting 210.19(A)(1) will have no net effect, due to 240.4(C). But for smaller loads, this would allow the use of 240.4(B), and would make the proposed install in the OP NEC compliant.
[But until 210.19(A)(1) gets deleted or amended, the proposed install in the OP is an NEC violation.]
Cheers, Wayne
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
Worst one was supplier in oregon not knowing mc used anything other than 2 screw romex connectors for over 3/4 inch mc.
Stevenfyeager
Senior Member
- Location
- United States, Indiana
- Occupation
- electrical contractor
Stevenfyeager
Senior Member
- Location
- United States, Indiana
- Occupation
- electrical contractor
Yes many times on these car charging circuits if there’s quite a distance we will use aluminum SE cable and then change it over to copper in a junction box close to the charger and use number six copper conductors. It really cuts the cost too.
It goes like this for me:
One of our guys says " I called every supply house cant find it they said its not made"
I call manufacturer they say "we distribute thru xyz factory rep and abc electric supply call them".
I call abc electric supply "oh they dont make that its not in our computer".
I call factory rep "oh yeah they are a factory order 3-weeks out you order thru abc".
Me "Can you explain this to abc? Would you hold on a sec while I get abc on the line?"
I call abc and conference them to factory rep.
Part gets ordered arrived 3 weeks later.
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
I usually show them that they can get it. This case in peticular the counter guy just didn't know it was in their system and I ended up showing they had hundreds in their system and they just needed to order from beaverton
Birken Vogt
Senior Member
- Location
- Grass Valley, Ca
I just read on here you could order various wire types on ebay. So I went through and found 6 Cu SEU and SER as well as other sizes and configurations in any length you would want. Seems to come from Nassau.
mtnelectrical
Senior Member
- Location
- Essex, New Jersey
so, nobody has said it yet, but , what we need to run for 48 amps EV charger circuits are # 4 wire copper conductors. 
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Only if you use a 60C wiring method or your equipment has 60C rated terminals. With a 75C wiring method and 75C rated terminals, #6 Cu suffices.so, nobody has said it yet, but , what we need to run for 48 amps EV charger circuits are # 4 wire copper conductors.
Cheers, Wayne
mtnelectrical
Senior Member
- Location
- Essex, New Jersey
could you cite the code reference for that?
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
110.14(C) plus Table 310.16. The 60C ampacity of #6 Cu is 55A, while the 75C ampacity of #6 Cu is 65A.
Cheers, Wayne
dissonant
Member
- Location
- Honolulu, HI
- Occupation
- Electrical Engineer
I always took 110.14(C) as being required to use 60C ratings for circuits lower than 100A and up to 1 AWG and the 75C ratings for circuits above 100A or larger than 1 AWG...
- Location
- New Jersey
- Occupation
- Journeyman Electrician
If the terminals and conductors are rated for 75° C even if 100 amps or less you can still use the 75° C ampacity. NM cable has it's own 60° C restriction due to 334.80. IMO 334.80 needs to be removed from the code as it serves no real purpose when the cable is constructed using 90° conductors.