I will be preparing the electrical for a new hot tub installation. I have a sub-panel inside the house in the basement literally 2-3 feet from the panel. That panel also contains a 40AMP GFCI wired to a digital timer inside the house to a double-pole switch and outlet which turns the pool motor on and off that was installed by an electrician.

I would like to do the same thing with the hot tub so that I can keep the 50AMP GFCI breaker in the sub-panel out of the elements, then connect that to a turn-off switch outside which would then feed the hot tub. What I am confused on is the AMP rating for the switch. Do I need to purchase a 50AMP double pole switch (ex: https://bit.ly/2lwNOey)? The pool motor is using 12-3AWG out of the timer to a 30AMP double pole switch making the connection to the switch easy. If I run 6AWG from the 50AMP GFCI breaker to a switch, I am not sure how that could be connected. Can it be less gauge wire? Do I use crimped on connectors?

Any help/input would be appreciated.

  • Is the pool control using a relay or is the digital timer switching the full 40A? That's a big switch... – JPhi1618 Sep 3 '19 at 21:46
  • @JPhi1618 If the pool motor is using 12/3 20A then it is really 20A, despite the breaker being 40A. Which doesn't make sense to me - but also means the timer only needs to switch 20A. – manassehkatz-Moving 2 Codidact Sep 3 '19 at 21:53
  • The pool switch is a 30AMP double pole. It goes, 40AMP GFCI breaker > 12-3AWG > Intermatic Digital timer (something similar to this: amzn.to/2ke0wyJ) > 12-3AWG > 30AMP double pole switch > Outlet (not sure what NEMA). The timer is either on run (program), On or Off. – William Verbist Sep 3 '19 at 22:03
  • I think we'd need to see the manial for this hot tub. I can't believe they'd require 50/60A if 20A would do. Where does the "hot" come from? – Harper - Reinstate Monica Sep 3 '19 at 22:07
  • 30A switch puts a max. of 30A on the pool motor. 40A breaker may be OK there as long as the wire is rated for 40A but if the wire is 12 AWG then it is rated for only 20A. Something doesn't add up. – manassehkatz-Moving 2 Codidact Sep 3 '19 at 22:08

You can do A LOT of things, if your sub panel is actually "sized" for it. If your sub panel is 100 Amps, then yes, you can do that hot tub. But first things first.

  • That is a great point - it is only a 60AMP panel. I will be calling an electrician for this one. Thanks for all of your input! – William Verbist Sep 3 '19 at 22:26
  • Your total load cannot exceed the size of your sub panel, as a matter of fact, only 85% of it. Time for "Plan B" if the total load exceeds that you sub panel was designed to handle. But if your main panel is 100 amps... No can-do. If your main panel is 200 amps. You can more than likely do it. – Retired Electrician Sep 3 '19 at 22:28
  • Oops the 83% rule is only for the main , not feeders to sub panels. I have made this mistake . But after getting a inspection , I was lucky it was an industrial facility under supervision, residential only the service to the main, they need to make it clearer but it is spelled out if you have the nec hand book 2017 version. – Ed Beal Sep 4 '19 at 1:12
  • Nah, I'm retired ... But 👍 thx just the same🙂 I "rounded it off" lol – Retired Electrician Sep 4 '19 at 1:38

You may want to consider utilizing zero-cross solid state relays to do the switching. This will make/break contact @ 0V/0A. These are not cheap, but will be easier on the motors you are switching and extend their life. I did this on my pool pump using a timer to control the solid state relays. It works well.

Here is a beginning search at allied electronics. You can narrow down to your specific current/voltage needs.


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