Heat pump and breaker question

[Randall Clark]

Trane package heat pump (2016 mfg date). Panel box beside unit has one 60 amp breaker (not labeled). The label lists a max breaker size of 35 amps. Typically, a heat pump would have separate circuits for the heat strips and compressor. I understand there might be an internal fuse, but the mfg label should be followed. Any insight as to why there is only one circuit?

[Jerry Peck]

Trane package heat pump (2016 mfg date). Panel box beside unit has one 60 amp breaker (not labeled). The label lists a max breaker size of 35 amps. Typically, a heat pump would have separate circuits for the heat strips and compressor. I understand there might be an internal fuse, but the mfg label should be followed. Any insight as to why there is only one circuit?

My guess is this:

That "Panel box beside unit has one 60 amp breaker (not labeled)" is not a breaker if it is in a small panel (disconnect) next to the unit. Instead, that would likely be a "molded case switch" (no overcurrent tripping limit, it is just a switch inside the mold case which looks like a breaker.

If ... IF ... that is the case, then there would be an overcurrent device (breaker or fuse) back at the panel where that circuit originates.

If ... IF ... that is not the case, and that panel is a larger panel with other breakers in it, then it is likely a 60 amp breaker, and, yes, that would need to not be larger than the maximum rating shown on the label.

Do you have a photo of that panel?

[Jim Luttrall]

Trane package heat pump (2016 mfg date). Panel box beside unit has one 60 amp breaker (not labeled). The label lists a max breaker size of 35 amps. Typically, a heat pump would have separate circuits for the heat strips and compressor. I understand there might be an internal fuse, but the mfg label should be followed. Any insight as to why there is only one circuit?
So many unknowns here. But Jerry gave a good start.

[Randall Clark]

My guess is this:

That "Panel box beside unit has one 60 amp breaker (not labeled)" is not a breaker if it is in a small panel (disconnect) next to the unit. Instead, that would likely be a "molded case switch" (no overcurrent tripping limit, it is just a switch inside the mold case which looks like a breaker.

If ... IF ... that is the case, then there would be an overcurrent device (breaker or fuse) back at the panel where that circuit originates.

If ... IF ... that is not the case, and that panel is a larger panel with other breakers in it, then it is likely a 60 amp breaker, and, yes, that would need to not be larger than the maximum rating shown on the label.

Do you have a photo of that panel?

Thank you for the reply, Jerry. Very good information. I do not have a photo of that panel but it is one that has space for ~6 or 8 breakers. There is a breaker at the panel where the circuit originates with a 60 amp breaker.

[Dom D'Agostino]

Any insight as to why there is only one circuit?

Is it an older (original) breaker from a previously installed HVAC unit?
Newer equipment has a different requirement, including different ampacity.
Most package units around here have 2 breakers in a small panel enclosure, but this wasn't so strictly enforced years ago. Also the breaker size is wrong the majority of the time.

The interior panel may have separate breakers, as has been stated, or the original unit had built-in breakers.

[Randall Clark]

Is it an older (original) breaker from a previously installed HVAC unit?
Newer equipment has a different requirement, including different ampacity.
Most package units around here have 2 breakers in a small panel enclosure, but this wasn't so strictly enforced years ago. Also the breaker size is wrong the majority of the time.

The interior panel may have separate breakers, as has been stated, or the original unit had built-in breakers.

Yes, the breaker is definitely older.

[Larry Morrison]

I have a canned statement handy for this as I run across this in about 50% of the homes I inspect here in Southern Utah. About 3-4 years ago the City Code Inspectors started checking this (because of fires) on the Final Inspection for the CO but anything built before about 2014 is very likely to have a larger breaker than the manufacturer of the unit recommends/requires. Both Heat-Pumps and traditional AC units.

When homes are (were) built, the Electrician has no Idea what the unit will call out. So in the 80s a 60-70 amp breaker would be thrown in the panel, mid 1990s and on, a 50 amp...

In Utah at least, an HVAC tech can't change out a breaker at the panel if not also an electrician, so even new energy efficient installs will still have the OEM breaker.

[david shapiro]

On the faint chance . . . if the conductors coming from the 60 amp breaker are sized appropriately, this could be legal if a local cutout for it is fused, with 30 or 35 amp cartridges.

[Randy West]

Larry Morrison described my area in AZ exactly. Up to the early 2000's the electricians would put a 60 amp breaker in the main panel for the AC, and the hvac tech would put in the proper size fuses at the AC disconnect. Then we started seeing disconnects at the ACs without overcurrent protection, and of course newer ACs are more efficient so those 60 amp breakers in the main panels can be considerably oversized. I also see 20 year old homes where the AC has been replaced with a more efficient unit and the tech never checked/changed the fuses at the AC. A very common problem here.

[Stuart Brooks]

I ran across this frequently in my ?old days?. The original unit called for a higher amperage breaker than the replacement unit and the installers didn?t bother to check. So if you run into a house older than the heat pump, check the breakers.