I have three 3 phase 240 volt commercial dryers with name plate ratings of 79 amps. The name plates state that a 100 amp breaker is "recommended". The delima I have is that I have existing 125 amp circuits that I can use without making any changes. 422.10 requires a branch circuit "not less than" 125% for continuously loaded appliances. Since the name plate doesn't give me maximum size overcurrent device do you think I will be OK with the 125a breakers or should I change them to 100a breakers.
Commercial Dryer overcurrent protection
- Thread starter johnnyp
- Start date
- Status
- Location
- Massachusetts
Re: Commercial Dryer overcurrent protection
I would go with what the manufacturer recommends, sceepe's suggestion sounds good.
I would go with what the manufacturer recommends, sceepe's suggestion sounds good.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
Re: Commercial Dryer overcurrent protection
if the instructions say to use a breaker would you not be at least technically in violation if you used a fuse?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Re: Commercial Dryer overcurrent protection
If no maximum OCP is specified, I'd leave well enough alone.
If no maximum OCP is specified, I'd leave well enough alone.
john m. caloggero
Senior Member
Re: Commercial Dryer overcurrent protection
Johnny, The rating of the dryer in questions sounds like an industrial dryer. It is not classified as an "Appliance" according to Article 100. I assume it is a listed by a testing laboratory, so the installation instructions must be followed as required by 110.3(B). If it is a listed product, the motor and heater loads are precalculated and the 79 amp rating includes the 125% required for the motor load in 430.22 and 430.24. Seems to me that the 100 amp breaker is the way to go.
Johnny, The rating of the dryer in questions sounds like an industrial dryer. It is not classified as an "Appliance" according to Article 100. I assume it is a listed by a testing laboratory, so the installation instructions must be followed as required by 110.3(B). If it is a listed product, the motor and heater loads are precalculated and the 79 amp rating includes the 125% required for the motor load in 430.22 and 430.24. Seems to me that the 100 amp breaker is the way to go.
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