Max overcurrent protection for AC units

[nrichards]

Did an inspection where home had 2 AC units. Data plates on units indicate max. overcurrent protection of 20 and 30 amps. Breaker in panel labeled for AC's was one 50 amp? Does'nt each unit need its own dedicated circuit?

[Bruce A. King]

Did you look inside the subpanel next to the units? This is where you will typically find the individual breakers.

[Joe Funderburk, CMI]

Bruce is correct. However, once you identify the breakers for the AC condensers, you should carefully match them to the data plates. About 40% of every condenser I see has an inappropriately sized breaker. Seems most HVAC guys only carry the 30 amps on the truck. No matter what the condenser requires, it gets a 30 amp.

[nrichards]

It was my understanding that the breakers at the units are disconnects only and do not act as overcurrent devices? Does not matter size of disconnect I thought...

[Bruce A. King]

You have to confirm what they are, when a subpanel is used like you descibed they should be breakers with the amps indicated on them. If the subpanel has disconnects only it is wrong, If the panel breakers are the right size the exterior can have a straight disconnect or any size breaker (but larger than the panel one).

In summary, you can have the properly sized breaker inside the main panel or at the disconnect location.

[nrichards]

Thanks for your replies, let me clarify my original question. Each unit has a single breaker disconnect next to the compressor. The main panel is located in the garage with one 50 amp breaker that appears to be for both units.

[Bruce A. King]

If the disconnects do not have any amps marked on them then its wrong.

So there is no subpanel? Just two disconnect boxes? That means there is a splice or double tap somewhere.

I have never seen a subpanel with disconnects inside with no overcurrent protection but its possible.

Proper terms would be:
double pole disconnect (not a breaker)
double pole breaker (also functions as a disconnect)