A/C Over-Current Protection Fuses or Breakers?

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David40

Member
I was reading my code book and caught the section on over-current protection for A/C units. The interpretation I got is that if a unit calls for a "Max. Fuse Size" that this indicates the unit is only UL approved for fuses and that fuses must be inserted in that feed somewhere. They go on to discuss the nomenclature for units approved for both fuses and breakers. ( Can't remember the section where I found it )
I am going to be installing the wiring for a couple of mini-split A/C systems and the specs call for the "Max. Fuse Size" or 15 Amps. The A/C guy looked at me like I was crazy and told me other electricians he's worked with say they have not used fuses in years. So what's up with this? Is it something new, or something old that nobody enforces any longer?
Thank for any input.
 

raider1

Senior Member
Staff member
Location
Logan, Utah
110.3(B) requires that listed equipment be installed in accordance with any instructions that are part of the listing.

So if the manufacturer states that you must use fuses then you must use fuses.

Chris
 

ceb58

Senior Member
Location
Raeford, NC
Some name plates will state xx-amp max fuse. You then must use fuses.
Some will state xx-amp max fuse or HVACR type breaker. You then can use ether. A fuse or breaker.
I got tagged on this once. I just gave the name plate a quick glance for the amp rating. I installed the breaker in the panel and a non-fusible disco at the unit. The name plate stated max. fuse size. I had to replace the disco with a fusible one.
 
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augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
To back up what ceb58 stated... some will say "max fuse" and then hide a little footnote, "or HACR breaker" elsewhere on the nameplate, so look carefully.
I seldom find HVAC equipment that isn't listed for fuse or breaker, but I often find refrigeration equipment that is only listed for fuse protection.
 

marti smith

Senior Member
Augie, allow me a moment to expose my youth: why is it that that refrigeration eqp. is only listed for fuses?
 
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