Hfalz1
Member
- Location
- Houston, Tx.
- Occupation
- Electrician
If i have a 400A service coming in to a 400A disconnect, can i put 200A fuses in it to feed a 200A ATS?
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- Thread starter Hfalz1
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drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
- Occupation
- Registered Professional Engineer
Yes, but you'll also need to do something to assure that nobody else installs 400A fuses in the future.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
dr, where is that in the NEC?
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
I don't think that's correct.
Coppersmith
Senior Member
- Location
- Tampa, FL, USA
- Occupation
- Electrical Contractor
If it's a service rated ATS, then it doesn't matter, the breaker in the ATS will protect it. If it's not service rated, then an OCPD ahead of it is required that is properly rated. In this case, 200 amps. If you are using fuses as the OCPD, then I think that a sign on the disconnect such as "maximum safe fuse size is 200 amps" would be sufficient.
qcroanoke
Sometimes I don't know if I'm the boxer or the bag
- Location
- Roanoke, VA.
- Occupation
- Sorta retired........
There is also a physical size difference between 400 and 200 amp fuses.
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