Breaker - fused disconnect question

[Chamuit]

I'm out in the field today but I'd like to respond to the inspector today if someone could help me with code sections.

We converted an area from a large conditioned space to a smaller conditioned space and a large unconditioned space. The contractor changed out the condensers. The old required a 50A MOCP and the new a 25A MOCP. Because there were no 25A breakers available when the job was done, I installed a fusible disconnect with 25A fuses. Inspector says I can't do that. Am I wrong?

 

[rcarroll]

You're not wrong. I approve that often.

 

[electrofelon]

I'm out in the field today but I'd like to respond to the inspector today if someone could help me with code sections.

We converted an area from a large conditioned space to a smaller conditioned space and a large unconditioned space. The contractor changed out the condensers. The old required a 50A MOCP and the new a 25A MOCP. Because there were no 25A breakers available when the job was done, I installed a fusible disconnect with 25A fuses. Inspector says I can't do that. Am I wrong?

What did he say the issue was? Barring things like AIC/lack of a series rating I can't think of an issue. In fact fuses may be "better" for such an application.

 

[Dennis Alwon]

Well it depends on the size of the conductor coming from the panel to the disconnect. Assuming the wire is rated 50 amps then you are compliant

BTW, there are 25 amp breakers available- at least for single phase panels.

 

[charlie b]

You satisfied the manufacturer's requirement to not exceed 25 amps for the overcurrent protection. The wires from the 50A breaker to the 25A fuses comprise a feeder, and that feeder's conductors are rated for at least 50 amps. There is nothing to prevent using a wire that is rated for more than 25 amps and protecting it with a 25 amp fuse. So I agree that your installation is compliant.

 

[charlie b]

You asked for code citations. I would offer 240.4, in that the "feeder" I mention above and the branch circuit conductors between the 25A fuse and the equipment are all protected against overcurrent at their ampacities. I would also offer 110.3(B), in that you complied with the manufacturer's instructions related to overcurrent protection for the equipment.

 

[Chamuit]

It is #6. Thanks for the Code sections, Charlie.

 

[LarryFine]

Let's hope the inspector doesn't say that the EGC after the fuses must be upsized.

 

[iceworm]

Is there an issue if the installation literature refers to a "Circuit Breaker" instead of generic overcurrent protection?
It is rare I ever deal with equipment that has a MOCP listed, so I don't know.

 

[retirede]

Is there an issue if the installation literature refers to a "Circuit Breaker" instead of generic overcurrent protection?
It is rare I ever deal with equipment that has a MOCP listed, so I don't know.

It used to be common for some of these units to call for fuses specifically. I don’t think I’ve seen one that required a breaker.
Buy, yes, mfr’s instructions must be adhered to.

 

[rcarroll]

The instructions usually require a HACR rated breaker or fuses.
I've not seen HACR FPE or Zinsco breakers.

 

[iceworm]

rc -
What prompted the reference to "FPE" or "Zinsco"?

 

[charlie b]

Let's hope the inspector doesn't say that the EGC after the fuses must be upsized.

That would be a case of what I would call, "malicious compliance." If you have a 50A OCPD, the correct EGC size is #10. If you have a 25A OCPD, the correct EGC size is #10. But if you leave the #6 wires after the fuses, where a #10 would have sufficed for the ampacity requirements, then the rule book might guide one to increase the EGC (or replace the #6 with #10). Another example of where the rule book does not make sense.

 

[rcarroll]

rc -
What prompted the reference to "FPE" or "Zinsco"?

They are not HACR rated. When using breakers for OCP they need to be HACR rated.

 

[jim dungar]

They are not HACR rated. When using breakers for OCP they need to be HACR rated.

All UL489 breakers are automatically HACR rated, and have been for several decades (maybe as far back as the 80's). A specific HACR label no longer is required as part of the UL Listing, however some manufacturers still offer it, maybe for those AHJ that don't update their requirements.

 

[rcarroll]

Thank you. I didn't know.

 

[Chamuit]

Just to get back with you all. The inspector still insisted that the breaker had to also be 25A. He couldn't cite a code reference. So, for $8.95, I just changed the breaker to a 25. Like arguing with a brick wall. Exasperating.

 

[kwired]

All UL489 breakers are automatically HACR rated, and have been for several decades (maybe as far back as the 80's). A specific HACR label no longer is required as part of the UL Listing, however some manufacturers still offer it, maybe for those AHJ that don't update their requirements.

But those FPE and Zinsco originals were discontinued back in the 80's, so if using an old breaker it may not be HACR rated, I'm presuming any listed/classified replacements made later on would be HACR rated though.

 

[Chamuit]

Regular GE panel, not even 2 years old. It passed, although I did leave a nice note on the turndown sheet.