Matt Mckenzie
Member
- Location
- United States
Does a 120 volt vacuum with a 25 amp nameplate load really need an #8 thhn? If it were 24 amp nameplate #10 thhn would work? Motor load? 125%?
Commercial vacuum
- Thread starter Matt Mckenzie
- Start date
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kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If you have 75 degree C terminals (if new equipment that is pretty much standard today), then 25 x 1.25= 31.25. 10 AWG, 75C conductor has an ampacity of 35.
If you must use conductors at 60C rating then yes you must use at least 8 AWG.
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
I think kwired picked up on your "error" but please explain why you think a 25 amp motor needs a #8 wire? And by the way, what is the horsepower rating on the nameplate? Read article 430 or Mike Holt's instructions on sizing motor feeders and you will learn why I asked this question.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
My reply was based on having a FLA of 25 amps regardless of how it was determined. No more details then OP gave we don't know if 25 is the FLA or is some other value.
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
I knew that, I just didn't want to ask for more information from him without acknowledging that he had actually received the answer from you.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If the 25 amps mentioned is recommended breaker size the actual FLA may very well be low enough that 14 AWG conductors are code compliant.I knew that, I just didn't want to ask for more information from him without acknowledging that he had actually received the answer from you.
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