HVAC disconnect question

   / HVAC disconnect question #21  
Here we go, over thinking again. The old adage KISS applies here!
 
   / HVAC disconnect question #22  
Well, ive been doing commercial and industrial electrical for 35 years. All our motors have a fused disconnect. And all motor control panels have multiple fuse protection devices along with heaters . Breakers are always rated 125% over motor loads. Offer limited protection .


but i digress from OP. The states i work in require that we follow nameplate on device. For instance my AC unit has a nameplate that states minimum fuse size. I HAVE to use fuse. If label says minimum OCPD (over current protective device) then you can use a breaker. All this is superseded by whatever manufacturer requires. Most A/C Manufacturers install paperwork i used to read REQUIRED a fused disconnect, so it was never an issue.
 
Last edited:
   / HVAC disconnect question #23  
Well, ive been doing commercial and industrial electrical for 35 years. All our motors have a fused disconnect. And all motor control panels have multiple fuse protection devices along with heaters . Breakers are always rated 125% over motor loads. Offer limited protection .


but i digress from OP. The states i work in require that we follow nameplate on device. For instance my AC unit has a nameplate that states minimum fuse size. I HAVE to use fuse. If label says minimum OCPD (over current protective device) then you can use a breaker. All this is superseded by whatever manufacturer requires. Most A/C Manufacturers install paperwork i used to read REQUIRED a fused disconnect, so it was never an issue.
I have had a number of corrections (from inspectors) due to the manufacturers label saying minimum fuse size, and then being required to install a fused disconnect to pass inspection.
If it states minimum OCPD (overcurrent protection device), then a breaker in the panel can be the protective device and non-fused cheap disconnect can be installed next to the HVAC unit.
 

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