50amp 8gauge

[Debbie_Affeldt]

i understand 8 awg thhn wire is exceptable on a 50 amp circuit breaker if run three wire in conduit by itself , Question , does this mean that this would be a dedicated circuit to run a peice of equipment or is it ok to supply a subpanel that would run different circuits ?

[lkage (Larry Kage, CMI)]

@Debbie_Affeldt

i understand 8 awg thhn wire is exceptable on a 50 amp circuit breaker if run three wire in conduit by itself , Question , does this mean that this would be a dedicated circuit to run a peice of equipment or is it ok to supply a subpanel that would run different circuits ?

Respectfully, the question appears to indicate, to me, a sufficient lack of electrical understanding that I would recommend getting a qualified electrician to do what you need done.

[Debbie_Affeldt]

Thanks for the reply Larry ,in what respect is the sufficient lack of electrical understanding in your opinion ?
Deb

[Jim_Port]

I believe you are asking is #8 in conduit can have 50 amp overcurrent protection.

A feeder to a sub panel need to be 4 conductors.

[Debbie_Affeldt]

@Jim_Port

I believe you are asking is #8 in conduit can have 50 amp overcurrent protection.

A feeder to a sub panel need to be 4 conductors.

Yes Jim, thought i read 50 amp on 8awg THHN wire is ok for 50amp breaker useing three conductors , To me that would possibly mean a dedicated circuit running one peice of equipment, with that said would it be acceptable to run 8 THHN wire, three wires, in conduit add a forth that is twelve gage of a different rating and feed a subpanel ?

Deb

[rmeier2 (Robert Meier)]

@Debbie_Affeldt

i understand 8 awg thhn wire is exceptable on a 50 amp circuit breaker if run three wire in conduit by itself , Question , does this mean that this would be a dedicated circuit to run a peice of equipment or is it ok to supply a subpanel that would run different circuits ?

Yes, THHN is a 90 degree conductor with a 75° C ampacity of 50 amps. Since almost all modern terminals are rated for 75° C you can use the 75° C ampacity of #8 AWG THHN. This would apply to conduit and wire and MC cable. If you’re using NM cable then the ampacity is limited to the 60° C rating {334.80} which is 40 amps.

[Martin_Brooke]

@Robert_Meier

Yes, THHN is a 90 degree conductor with a 75° C ampacity of 50 amps. Since almost all modern terminals are rated for 75° C you can use the 75° C ampacity of #8 AWG THHN. This would apply to conduit and wire and MC cable. If you’re using NM cable then the ampacity is limited to the 60° C rating {334.80} which is 40 amps.

Best answer, very well said:D

[tspargo (Tim Spargo, CMI)]

with that said would it be acceptable to run 8 THHN wire, three wires, in conduit add a forth that is twelve gage of a different rating and feed a subpanel ?

Deb… can you clarify? Are you meaning to pull a 4th wire as the Equipment Grounding Conductor? #12 would be undersized via 250.122, which indicates #10 CU/Copper wire for 40 - 60 Amps, if I understand you… if I don’t, maybe elaborate a bit.