Correct amperage for pool heater

[shwn2405]

Been a long time follower of trouble free pool and I respect all the advice that I get from this website. That being said my dad has been electrician for 45 plus years. But he's getting old. Cancer and other s*** from working at these refineries has taken a toll on him. My question is I have 6 gauge 50 amp running to my pole barn. I hardly ever have power pulling through my pole barn but through my pole barn I have the wires run to my pool. That being said, I have my variable speed pump that I run mostly on 1750 which is at 1.5 horsepower. My question is, what is the biggest heat pump I can put on my pool? Can I run a 6 gauge 50 amp while continually running my pool pump or should I get a heat pump that runs on 8 gauge at 40 amps? Or should I use a meter to see how many amps my pump is pulling at 1750 RPM? Just trying to gather some information before I try to buy heat pump, thanks guys

 

[zero_sports]

Hi,

Assuming you are talking about 240v circuit, your 50 amp breaker have a maximum capacity of 240v x 50a = 12000 watt. You should aim at maximum 80% of that capacity so 9600 watt. Substract the max continuous watt your pump use ( not peak watt ) and you have the power available for your heatpump.

 

[ajw22]

Do you want to conform to National Electrical Codes or just want it to work?

NEC requires that a breaker be loaded to no more then 80% amperage or 40 amps on a 50 amp breaker.

NEC also requires the maximum motor data plate amperage be considered, not the lower speed you may say you run it at.

Things may work if you don’t follow the NEC however long term problems can show up.

 

[zero_sports]

1.5 HP pump is about 1100 watts. With 8500 watt available ( 9600 - 1100 ), you can put a 140000 BTU heappump ( 8500w x 17 = 144500 BTU ).
It's more than enougth for your pool. If you want your heatpump to be the most efficient, you need the smaller one that does the job.