6/3 NM cable

[nizak]

Can residential feeders that are 6/3 NM be protected by 60 Amp O.C. Protection?

55A not a standard size breaker.

Thanks

 

[infinity]

Yes if the calculated load is 55 amps or less.

 

[retirede]

Perhaps. As long as at least one of these is true:
1. The required circuit ampacity (load) does not exceed 55A. (A 48A EVSE requires a 60A circuit, so in that case, no).
2. You are in Massachusetts. They have an amendment for this case.

 

[nizak]

Yes if the calculated load is 55 amps

Thank you.

 

[kwired]

Thank you.

Keep in mind that calculated load will be 125% of continuous load. So you are looking at max continuous load of 44 amps that can be supplied or 55 amps of non continuous load. Or 125% of continuous plus 100% of non continuous can not be more than 55.

Motors or air conditioning needs to follow art 430 or 440 and you possibly could have even higher OCPD in those cases, but MCA or 125% of FLA still would need to be no more than 55.

 

[tortuga]

Perhaps. As long as at least one of these is true:
1. The required circuit ampacity (load) does not exceed 55A. (A 48A EVSE requires a 60A circuit, so in that case, no).

They should bring back 5 AWG like a 5/2 NM-B it would be perfect for EV's as it would be about 63 amps, there is 5AWG in the old codes.

 

[infinity]

They should bring back 5 AWG like a 5/2 NM-B it would be perfect for EV's as it would be about 63 amps, there is 5AWG in the old codes.

Didn't that end about 1943?

 

[tthh]

Or just make #6 SE widely available and ditch the #6 NM.

 

[curt swartz]

Or just make #6 SE widely available and ditch the #6 NM.

I agree 100%.

Actually get rid of NM cable entirely. No reason to have a cable that has unknown conductor insulation, can't be installed in wet locations and is limited 60C.

The only real difference between NM and SE is the paper fillers and the unmarked conductors. Get rid of the paper and use THHN/THWN-2 insulation on the conductors.

 

[electrofelon]

I agree 100%.

Actually get rid of NM cable entirely. No reason to have a cable that has unknown conductor insulation, can't be installed in wet locations and is limited 60C.

The only real difference between NM and SE is the paper fillers and the unmarked conductors. Get rid of the paper and use THHN/THWN-2 insulation on the conductors.

A men brother

 

[Fred B]

I agree 100%.

Actually get rid of NM cable entirely. No reason to have a cable that has unknown conductor insulation, can't be installed in wet locations and is limited 60C.

The only real difference between NM and SE is the paper fillers and the unmarked conductors. Get rid of the paper and use THHN/THWN-2 insulation on the conductors.

A men brother

Actually that might get rid of the handyman, DIY from the electrical field. Haven't seen one that can bend pipe.

 

[Eddie702]

I think of it another way. Isn't NM although the cable assembly is rated for 60C max the wires are actually THHN rated at 90C although unmarked?

I mean if SE cable is allowed to run 75C why is NM not allowed to run at 75C? SE is usually XHHW and NM is THHN both 90C conductors although NM wires are unmarked

Also, if someone knows when was NM cable restricted to 60C? It was commonplace to use it to feed HVAC equipment that called for 75C wire using the ampacity charts for motors and HVAC equipment that allowed over/fuse/breaker MCA & MOCP?