hardworker
Senior Member
What awg conductor would you recommend for a 150amp sub-panel, that is 110ft distance from the 400amp main panel? What size for the 3 conductors and what size for the ground?
150amp sub-panel - awg question
- Thread starter hardworker
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- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
There is a whole bunch that you didn't tell us. Single phase or three phase? Voltage level? Copper wires or aluminum? Calculated load? Feeder breaker rating (i.e., on the 400 amp panel)?
Presuming this is a 120/240 volt, single phase panel, the load is 150 amps, the feeder breaker is 150 amps, and the wire is copper, I calculated that 1/0 wire will give you a 2% voltage drop. So I see no need to go higher than that. Therefore, the #6 EGC called for in 250.122 will be adequate.
Presuming this is a 120/240 volt, single phase panel, the load is 150 amps, the feeder breaker is 150 amps, and the wire is copper, I calculated that 1/0 wire will give you a 2% voltage drop. So I see no need to go higher than that. Therefore, the #6 EGC called for in 250.122 will be adequate.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Generally for 100 feet you don't need to worry much about VD.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
What's the application? In Charlie's response you would need to use MC cable or conduit and wire for #1/0 to work. SE cable would require larger conductors due to the 60? C rating of the cable.
hardworker
Senior Member
It is a conduit run, copper conductors. 120/240 single phase. 150amp sub-panel supplying lighting, general outlets, HVAC w/ heat pump in a studio.
You say I need 1/0 with #6 ground. I was thinking #1 with #6 ground.
Please comment. thanks.
You say I need 1/0 with #6 ground. I was thinking #1 with #6 ground.
Please comment. thanks.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
#1 THHN Cu is good for 130 amps, next size up 150 amps. Load would need to be 130 amps or less.
hardworker
Senior Member
Most likely 130 amps will run the studio fine, but I don't know for sure. The heat pump condenser requires a 45amp breaker, the air handler w/ the 15kw heat strip requires a 30amp and a 60amp breaker. The rest of the studio is just lights, refrig, computers, makeup area with normal hairdryer. 1800 sq.ft studio.
How many amps would you guess it will pull?
How many amps would you guess it will pull?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I wouldn't guess, I would do a load calculation if I were you.
hardworker
Senior Member
Let's narrow it down. What do you think the HVAC will pull? You have some idea based on the required breakers.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
15000/240= 62.5 amps. Now if a heat pump is involved and if it can be turned on at the same time the strips are engaged then you need to add that.
I think it would be wise to do calculation although I suspect 150 amps will be fine.
I think it would be wise to do calculation although I suspect 150 amps will be fine.
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