ECN Forum Forums General Topics of the Trade General Discussion Area Code legality question on Air conditioning and spa

Ok this may be a pretty obvious thing to someone on here but here goes in any case. I have a customer who wants to use their existing Air conditioner feeder to power a new hot tub since it is located 10 feet from it. They mentioned they realize it would need "a switch" so they both would not run at the same time. Obviously you could use a manual transfer switch and a new disconnect to do this sort of a thing. I was trying to figure out if anyone has ever had this requested. It seems like that is a pretty funky setup as opposed to running a new feeder from the panel etc. My other thought was along the lines of tapping the A/C line using motor tap rules/ calculations for this. Does anyone know what the exact calculation would be involved and what are your thoughts on either of these two options. Personally, I think the guy would end up spending the money on the transfer switch etc that he would save on the labor and extra wire and conduit plus it would be pretty ugly....

On the face it may not be that crazy an idea since you usually use a hot tub in cold weather when the A/C is off but actually doing it may be troubling.
I don't think you really need "transfer equipment" per se but you will need something that interlocks the circuits.
You might actually be able to do this by interupting the controller for the AC on the low voltage side. (Your AHJ will answer that)
How many amps are we talking about and what size is the branch circuit going to the AC? I bet you a cold one this has a bigger breaker than you can support with the wire if this was sized with the condenser label.
The hot hub will need a conductor sized with 310.16, not 440 (or the HVAC label). Just because he sees a 50a in the panel does not mean there is 6ga wire going out there.
You also find 680 wiring methods are more stringent than 440 and you may need a neutral that is not there.
I really don't know enough about what you have to say yes or know but I know there are several land mines along the way.
I would start with the spa label, then look at 680 and 310.16 to see if the wire/wiring method will work. You may hit the wall right there.

Without knowing the particulars - you might be able to both with out the transfer switch - maybe not...

Either way I would avoid to hockiness of a T-switch as there are some seasonal changes where one would want both. And its a grounding and bonding nightmare.