6/2 CU cable: 60amp cb?

[philsoma]

For the record, what 80% rule?

I was referring to the idea that the load should be no more than 80% of the cb rating.




















5 of the

 

[philsoma]

You guys convinced me. I will go with the 50-amp setting on the EV charger, using 40amps.

 

[infinity]

You guys convinced me. I will go with the 50-amp setting on the EV charger, using 40amps.

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.

 

[retirede]

I was referring to the idea that the load should be no more than 80% of the cb rating.

 

[tom baker]

There are a few supply houses around here that suffer from the "If I never herd of it they must not make it I cant be bothered to look" plague.
You can get copper SE down to #8 from some manufacturers but its a large minimum order.

I used to get “ I have never heard of that”
When I knew what it was I needed

 

[kwired]

Yes, that's the part that makes no sense, as ampacity is a continuous rating. Minimum ampacity required for a 48A continuous load should be 48A.

Cheers, Wayne

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]

For the record, what 80% rule?

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]

210.19(A) says minimum conductor ampacity is to be 100% of non continuous load plus 125% of continuous load.

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]

I used to get “ I have never heard of that”
When I knew what it was I needed

Worst one was supplier in oregon not knowing mc used anything other than 2 screw romex connectors for over 3/4 inch mc.

 

[Stevenfyeager]

You can order 6 seu copper online or another option is 4 AL SE to an ac disconnect then copper 6 thhn in conduit to the copper

 

[Stevenfyeager]

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.

 

[tortuga]

I used to get “ I have never heard of that”
When I knew what it was I needed

Worst one was supplier in oregon not knowing mc used anything other than 2 screw romex connectors for over 3/4 inch mc.

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]

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.

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]

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.