Having an issue with inspector

[texie]

This just happened to come up on another forum.

Cheers, Wayne

View attachment 2568178

In my view, this is a perfect example of why the inspector is correct in the OP. This illustrates that the manufacturer has had the NRTL test it for both types of OCPDs and the results can lead to different values for fuses VS breakers based on how their overload system is built.

 

[mtnelect]

In my view, this is a perfect example of why the inspector is correct in the OP. This illustrates that the manufacturer has had the NRTL test it for both types of OCPDs and the results can lead to different values for fuses VS breakers based on how their overload system is built.

If you use a fuse instead of a HACR breaker it must be dual element.

 

[LarryFine]

If you use a fuse instead of a HACR breaker it must be dual element.

Which suggests and/or confirms that it's all about starting current.

 

[wwhitney]

This illustrates that the manufacturer has had the NRTL test it for both types of OCPDs and the results can lead to different values for fuses VS breakers based on how their overload system is built.

From my admittedly shallow perusal of UL 1995, there is nothing in the standard to indicate that the testing procedure depends on the nameplate MOCP, or what OCPD type is specified on the nameplate, or that when multiple OCPD types are listed on the nameplate, the testing is done multiple times.

As discussed in post 39, the standard tells you how to calculate MOCP, which matches the procedure in the NEC, and the Marking section 44.3(i) tells you to use "MAX. FUSE _____" or "MAX CKT. BKR. _____" or "Maximum overcurrent protective device." With no references to other sections of UL 1995, which is what I'm used to seeing in the Marking section--something like "mark it EXTRA GOOD when the unit complies with the requirements of section 73.27."

So as far as I can see, the nameplate marking OCPD type is just a manufacturer instruction, not backed up by any testing procedure.

Cheers Wayne

 

[kwired]

If you use a fuse instead of a HACR breaker it must be dual element.

Which suggests and/or confirms that it's all about starting current.

For non time delay fuse to hold for across the line starting it would have to be higher setting than the max OCPD typically marked on the unit, most if not all of them specifically say time delay fuse AFAIK.

 

[kwired]

Am I correct to assume that, unlike ducted heat pump systems, mini-splits do not incorporate a resistance heating option? I know that my MIL's Panasonic system just runs out of heating capacity both at low outdoor temps and when low on refrigerant.

I haven't seen as many of these as some people but have never seen one with any back up heat of any kind that was part of same system. They claim they are rated to use down to zero F or even below, but you know output has to be lesser the colder it is outside, particularly once you start getting below 10F.