Hvac

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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
OK, I opened up the unit this morning and this is what I found. First, remember that the label only has a option of one circuit, however there has been two ran to it. Inside the unit there was a fuse bank. Locations for 4 fuses. Two spots for the heating element and two for the compressor. The 2 for the heating was fused at 60 amps and that is what the inside sticker called for. The other two however were not used. They were bypassed. The inside sticker called for a 50 amp on this circuit. But it was run on a #10 on a 30 amp for the compressor. Interesting install.

Have you got the answer to your question now.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
The 2 for the heating was fused at 60 amps and that is what the inside sticker called for.

The inside sticker called for a 50 amp on this circuit. But it was run on a #10 on a 30 amp for the compressor.
Does the control wiring prevent the compressor and heat strips from running simultaneously?
 

lmchenry

Senior Member
My conclusion is this. First, the manufacturer only lableled this unit to be used as a single circuit piece of equipment. If one were to be able to separate it then yes you would not be in violation of 424.22. However, to bypass the internal fuse and do as done is not acceptable. Do you agree?
 

augie47

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Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
you say they were not used and they were bypassed. By "bypassed" do you mean the compressor was fed by a different circuit ?
The nameplate should give MCA and MOCP for the compressor (or as a no heat option). If the compressor is protected per that rating, I see no real problem.
In this area that is pretty common.
With the installed "fuse kit" it would appear the a single circuit could have been used, 60 amp for the heat and whatever the nameplate prescribes for the compressor.
The double fuse "kit" takes care of 424.22.
Hopefully you have a disconnecting means in sight for both circuits.
A case could be on 110.3 if the nameplate doesn't show a 2 circuit install, but I wouldn't doubt that is covered in accompanying literature.
 

lmchenry

Senior Member
Gus, the compressor was on a separate circuit and it did not go through the fuse kit. Interestingly the kit called for a 50 amp on the compressor circuit. However the outside label called for a 30 with no heat.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Gus, the compressor was on a separate circuit and it did not go through the fuse kit. Interestingly the kit called for a 50 amp on the compressor circuit. However the outside label called for a 30 with no heat.

strange.. perhaps the fuse kit was actually for a different unit
 
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