Air Compressor Feeder

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NSmithIN

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Valparaiso, IN
Sullair Air Compressor
250HP Compressor 5HP Cooling Fan
Wye-Delta Starter
Motor NP Amps -250HP Compressor Motor=279A 5HP Cooling Fan Motor=7.58A

NEC FLA 250HP=302A 5HP= 7.6A
Feeder calculation 302*1.25=377.5A + 7.6A=385A

Breaker - Eaton M6H3 800AF/600AT w/adjustable trip
2 sets of 3C 4/0KCMIL w/#4 ground 600V Tray Cable. Ampacity = 404A (75 deg C Ampacity corrected to 40 deg C ambient because compressor is located in Boiler Room)


Comments?
 
Does the unit have a nameplate or factory recommendations ?
It's been a few years since I've installed a Sullair but I thought at the time the mfg. had a "max fuse size". Failure to follow their requirements might negate the warranty.
 
NSmithIN said:
Sullair Air Compressor
250HP Compressor 5HP Cooling Fan
Wye-Delta Starter
Motor NP Amps -250HP Compressor Motor=279A 5HP Cooling Fan Motor=7.58A

NEC FLA 250HP=302A 5HP= 7.6A
Feeder calculation 302*1.25=377.5A + 7.6A=385A

Breaker - Eaton M6H3 800AF/600AT w/adjustable trip
2 sets of 3C 4/0KCMIL w/#4 ground 600V Tray Cable. Ampacity = 404A (75 deg C Ampacity corrected to 40 deg C ambient because compressor is located in Boiler Room)


Comments?
Click to expand...
Your ground wire is too small
 
Max Fuse Size

Max Fuse Size

augie47 said:
Does the unit have a nameplate or factory recommendations ?
It's been a few years since I've installed a Sullair but I thought at the time the mfg. had a "max fuse size". Failure to follow their requirements might negate the warranty.
Click to expand...


Good point. A fused disconnect switch may be in order.
 
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