HACR Circuit Breaker

[BadRoy]

I'm looking at a Trane spec plate and I see for US installations - BR CKT SEL CUR: 20 / 18 AMPS, Max Fuse or HACR TYPE CKT BREAKER: 45/40 AMPS - so I'm assuming this is telling me that any HACR breaker at or above 20 AMPS and less than or equal to 45 AMPS is ok to use - correct?:?

 

[augie47]

Your slash rating makes me think one rating is for 208 volts, the second for 240.
Once you select the proper one for your voltage, you are correct in that you can not exceed the maximum rating. The more you reduce that number the greater your chance of a nuisance trip on start-up.

 

[jumper]

To add:

Are not all modern common, IT, breakers HVACR rated?

 

[Gregg Harris]

To add:

Are not all modern common, IT, breakers HVACR rated?

Yes I believe since 1995

 

[Cavie]

some inspectors feel you must use the MAX size.

 

[Gregg Harris]

some inspectors feel you must use the MAX size.

That is the best way to go to prevent excess tripping .

 

[iwire]

That is the best way to go to prevent excess tripping .

I agree, if not now when the equipment gets older.

But that still does not make it an NEC requirement.

 

[iwire]

I'm looking at a Trane spec plate and I see for US installations - BR CKT SEL CUR: 20 / 18 AMPS, Max Fuse or HACR TYPE CKT BREAKER: 45/40 AMPS - so I'm assuming this is telling me that any HACR breaker at or above 20 AMPS and less than or equal to 45 AMPS is ok to use - correct?:?

I agree with Gus, it depends on what voltage you are running it at.

At 240 volt you could use as small as 14 AWG with a maximum of a 40 amp breaker.

 

[JDB3]

iwire; At 240 volt you could use as small as 14 AWG with a maximum of a 40 amp breaker.

I know that you are correct, but would you please post the code article for this. Can't find it again. Thanks

 

[ActionDave]

iwire; At 240 volt you could use as small as 14 AWG with a maximum of a 40 amp breaker.

I know that you are correct, but would you please post the code article for this. Can't find it again. Thanks

240.4 (D) and (G) and then the table takes you to 430 or 440