My pool pump draws about 11 amps and we just converted the pool to salt which requires powering a chlorine generator. This draws an additional 7 amps for a total of 18. When both are powered on, the breaker is tripping since it is only a 15 amp breaker. The pool guy said swap it out for a 25 amp breaker. I thought, however, that the solution was not this simple depending on the gauge of the wire on the circuit. Is there a way to figure out the wire gauge from looking at it? Should I just hire an electrician to check it out and determine if it needs a thicker gauge wire? Thanks

  • Is the circuit in question wired using a cable or in a conduit? Commented Jul 1, 2017 at 5:28
  • Your pool guy wants to burn your house down... The breaker is there to protect the wiring - so you're correct that it's not so simple and does depend on the gauge of the wire (and other things).
    – brhans
    Commented Jul 1, 2017 at 12:47
  • Your pool guy wants you to sign off on the project so he can get paid. After that, not his problem. Commented Jul 1, 2017 at 15:24

2 Answers 2


You could try the following to determine the gauge

  1. Cut the power off
  2. Open the connection and pull a wire off
  3. Use a wire stripper and find the largest hole it fits in

As to the rest of the question...

25 amps is nuts. You have 18 amps so a 20 amp breaker on 12 gauge wire should be sufficient. My bet is that, since you have a 15 amp breaker, that your wire is 14 gauge (it's pretty rare to find higher gauge wire on a lower amp circuit like that). When in doubt, run new wire. It's not worth it to try and guess. Know that your setup is sufficient.

I would suggest dropping new 10 gauge wire (more than you need in case you ever add anything else, like a Polaris, although you'll probably want a subpanel at that point) and adding a 20 amp breaker. If you're burying it, make sure it's UF and preferably in conduit. Take the existing wire and stick it in a box with a GFCI and make it an outlet.

  • 1
    The pump and chlorine generator are not listed to be used on anything bigger than a 20 amp circuit so whatever you do that is the maximum. There was no comment on GFCI'S any changes to the circuit would require the addition of a GFCI even if both the pump and generator have them built in to there cords. 12awg would be the correct size for a 20 amp circuit and the size is stamped on the wire/insulation if you don't have a good set of strippers to gauge the wire.
    – Ed Beal
    Commented Jul 1, 2017 at 14:20

Actually what we are talking about here is upgrading your power to your new system. NEC Article 210.20 (A) requires your wire size to no more than 80% of your calculated load. So if you have a load of 18A you should be installing 30A worth of power.

You can do this one of two ways:

  1. Rerun the pool circuit with a 30A breaker and a #10 conductor and connect to your equipment.

  2. Some how split the power and connect at least 5A up to the existing 15A circuit and run another 15A circuit to supply the rest.

Of course there are different combinations of circuits you can run, such as a 15A and a 20A. But according to the NEC in no case should you run more than 12A on a 15A circuit or 16A on a 20A circuit.

  • 1
    Can you put two <15A loads on a 30A cable? I didn't think you could. I believe you can run a circuit at nameplate capacity if the load is not continuous (not likely to run 3 hours or more). Commented Jul 1, 2017 at 15:43
  • @Harper -- I'm pretty sure you can put two <15A loads on a 30A circuit; however, you are correct that noncontinuous loads are allowed up to full circuit nameplate ampacity. Commented Jul 1, 2017 at 21:01

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