Can a 25, 35 or 45 amp breaker can be used to protect a branch circuit?

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maxbillington

Elec Engineer, Adjunct Faculty
Location
Colorado
Occupation
Prof Engineer
I had a staff member ask whether a 25, 35 or 45 amp breaker can be used to protect a branch circuit.

Article 210.3 lists branch circuit ratings as 15, 20, 30, 40 and 50 amps. Likewise, Table 210.24 provides a summary of branch circuit requirements. 25, 35 or 45 amp breaker sizes are not mentioned, even though they are commonly available.

Article 240.6 lists standard trip ratings as 15, 20, 25, 30, 35, 40, 45 and 50 amps.

So, even though a 25, 35 or 45 amp breaker is a standard size, can they not be used to protect a branch circuit?
 

jumper

Senior Member
Yes, you can have a branch circuit of those sized, but the devices and/or equipment must be rated for the size used. Conductor size must correct also.

You could not use 12# and 20A receptacles on a 25A or larger breaker.
 
I had a staff member ask whether a 25, 35 or 45 amp breaker can be used to protect a branch circuit.

You have to look at the definition of branch circuit:
Branch Circuit. The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).

and the limitations/exceptions in table 210.2 and elsewhere around the article. You can have a 400a branch circuit for some things.
 

peter d

Senior Member
Location
New England
Of course you can, they're just limited to very specific loads - water heaters, air conditioners and motor loads come to mind.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I had a staff member ask whether a 25, 35 or 45 amp breaker can be used to protect a branch circuit.

Article 210.3 lists branch circuit ratings as 15, 20, 30, 40 and 50 amps. Likewise, Table 210.24 provides a summary of branch circuit requirements. 25, 35 or 45 amp breaker sizes are not mentioned, even though they are commonly available.

Article 240.6 lists standard trip ratings as 15, 20, 25, 30, 35, 40, 45 and 50 amps.

So, even though a 25, 35 or 45 amp breaker is a standard size, can they not be used to protect a branch circuit?


Are you asking whether or not those size breakers can be used on a receptacle or lighting circuit???
 

kwired

Electron manager
Location
NE Nebraska
I had a staff member ask whether a 25, 35 or 45 amp breaker can be used to protect a branch circuit.

Article 210.3 lists branch circuit ratings as 15, 20, 30, 40 and 50 amps. Likewise, Table 210.24 provides a summary of branch circuit requirements. 25, 35 or 45 amp breaker sizes are not mentioned, even though they are commonly available.

Article 240.6 lists standard trip ratings as 15, 20, 25, 30, 35, 40, 45 and 50 amps.

So, even though a 25, 35 or 45 amp breaker is a standard size, can they not be used to protect a branch circuit?
You are missing one part of 210.3:

The rating for other than individual branch circuits shall be 15, 20, 30, 40, and 50 amperes.

An individual branch circuit can be any rating, multi-outlet branch circuits need to be 15, 20, 30, 40 or 50.
 
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