Minimum overcurrent protection required for an apartment unit

Tainted

Senior Member
Location
New York
Occupation
Engineer
Each apartment unit is fed by a 2-pole 50A circuit breaker. What is the minimum overcurrent protection required for each unit? Meter bank is indoors and provide power to each unit. Each dwelling unit panel is technically considered a sub panel.

225.39 only applies to branch circuit and feeders outside of the building which means it doesn't apply
230.79 only applies to services which doesn't apply.

My gut is telling me 60A is the minimum but I don't know if it's true or how to prove it.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
There is no minimum amp for a feeder afaik. We always used 60 amps for our needs and that makes sense but a feeder just has to be as large as the calculated load for that panel.
 

Tainted

Senior Member
Location
New York
Occupation
Engineer
There is no minimum amp for a feeder afaik. We always used 60 amps for our needs and that makes sense but a feeder just has to be as large as the calculated load for that panel.
You're talking about feeders but I'm talking about overcurrent protection.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
You're talking about feeders but I'm talking about overcurrent protection.
The overcurrent protective device must match the feeder ampacity. In essence if you talk about a feeder ampacity then you are talking about the overcurrent protective device because they work together. If your calculated load is forty amps then you could run #8 but because of the #8 you are limited to 40 amps. The is no minimum for overcurrent protective device that I know.
 

Tainted

Senior Member
Location
New York
Occupation
Engineer
The overcurrent protective device must match the feeder ampacity. In essence if you talk about a feeder ampacity then you are talking about the overcurrent protective device because they work together. If your calculated load is forty amps then you could run #8 but because of the #8 you are limited to 40 amps. The is no minimum for overcurrent protective device that I know.
I see your point, just wanted to make sure we are on the same page. Thank you. I've seen mixed responses from other threads
 
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