I'm installing a whirpool tub in our master bath and I know ideally it should be on a separate breaker, but I have no room in my box for another switch. I temporarily hooked it up to the dedicated breaker for our A/C unit (nothing else running off that breaker). I ran both the A/C and the whirlpool pump for about 45 minutes. I started up the A/C while the pump was running and I also started up the pump while the A/C was running. It never tripped the breaker. Can I keep both the A/C and the pump on the same breaker?

 

We need to know the "ratings" of the 2 motors, specificaly the "full-load current" rating and the rated HP. Look for this info on the motor "name-plates" and any installation/service manuals that you may have.Also-----waht is the rating of the CB which protects the 2 motor-Branch-circuits.?

 

The pump is 1/2 HP/10.5 amps.
The A/c is 10.4 amps.
The CB is 20 amps.
I know the full load is slightly over the 20 amps, but the pump would not be run for probably more than 15 minutes at a time, unless of course my wife decideds to take one of those extra long soaks - still probably not longer than 30 minutes before the water starts to cool (there is no heater with this unit).

Two more questions;

I noticed that most/possibly all the outlets in the house are 15 amp outlets even if they are run off a 20 amp circuit. Is there any danger in that?

All the wire in the house is 12 guage (even on the 15 amp circuits). Can I change the 15 amp CBs to 20 amp?

 

I'm baffled that the 20 amp CB doesn't trip on the motor starting-surge-is it a Federal-Pacific CB? The breaker may deteriorate from over-heating because of conducting it's rated amps over a prolonged period.Much depends on the "duty-cycle",i.e., for what time-period are both motors in operation?

The Code permitts connecting 15 amp receptacles to a 20 amp Branch-Circuit.

It's best to have 15 amp breakers protecting 20 amp conductors. The lower the rating of a breaker protecting a circuit, the safer the protection.

 

IMPORTANT: Tell us what type of panel you have: square D, siemens, cutler-hammer, westinghouse, fed.Pacific, GE, etc.

Really you should install a tandem breaker, and not have both loads on the same circuit (for safety and meeting NEC requirements).
gj