I have a Pentair EasyTouch Automation system for the pool, and it is installed on the outside of the house in a subpanel. When it was installed, I also ran 12ga direct burial wire around the pool landscaping, and from the pool, runs through underground conduit into the Panel. In the pic, the wiring is annotated w the red arrow. I was going to purchase an isolating safety transformer, likely the Intermatic PX300. This would supply between 12-14v AC power to the lights.

The PX300 comes with its own outdoor rated box. However, I don't want to install it on the wall. In the pic, where the yellow square is, is typically where the transformer for the salt generation cell would go, but I didn't go for a salt pool, so I have a big empty space in the panel. Can I remove the PC300 transformer from its box, and install it where the yellow square is in the panel pic, screwing is into the holes in the subpanel? Would 725.136(A) prohibit me from doing this?


PX300 Transformer: http://www.inyopools.com/Products/02400015000949.htm

Subpanel Subpanel

  • How were you planning to route the low-voltage wires out of the pool panel enclosure? Commented May 13, 2020 at 1:47
  • If I used the PX300 as designed, by using a knockout on the panel + conduit. But that's not a route I'd like to go.
    – puppycrack
    Commented May 13, 2020 at 2:01
  • That is, you'd rather not have a conduit extending inside the pool panel cabinet to reach the low-voltage transformer's enclosure? Commented May 13, 2020 at 11:45
  • @ThreePhaseEel hey, do you spot the alien breaker(s) in that panel? Think that's a problem? Manual is silent on breaker type. Commented May 14, 2020 at 20:42
  • @Harper-ReinstateMonica -- I'd have to see a clear shot of the label on the inside of the cabinet front to be sure what's going on Commented May 14, 2020 at 21:27

1 Answer 1


You are correct.

There are several points in Article 725 that are not going to allow that to happen. This would give you no viable plan to rigidly separate mains from low voltage wiring, and that won't do.

Further, it would violate NEC 110.2 and 110.3(B) because you'd be defeating the UL-approved enclosure design, and using the transformer contrary to instructions and labeling.

  • Thanks. At the risk of sounding pedantic, can you tell me why this is a bad idea? The transformer would be solidly mounted, in an outdoor enclosure, and it's not like LV wire would just pop off and hit HV lines. I realize code is there for a reason, but I'm genuinely puzzled as to the risk here. Thanks for your consideration.
    – puppycrack
    Commented May 14, 2020 at 1:51
  • Careful... when people want to know "the reason", often they aim to rationalize a way to cheat. Don't go there. At least one of the reasons is the lines interacting, resulting in mains voltage on a low voltage wire. Even more, if there is an accident, the fire inspector and ADAs will go through your setup with a fine tooth comb. Any codevio will be thrown in your face hard, as prima-facie evidence of negligence / liability / non-coverage. Commented May 14, 2020 at 2:34
  • @puppycrack What wiring method were you going to use from the pool panel to the lights, for that matter? Commented May 14, 2020 at 11:57
  • 1
    @ThreePhaseEel -- no EGC required. 12ga direct burial rated LV wiring would exit the transformer enclosure, run ~60' in underground conduit, and then branch in 2 directions from ground installed waterproof box. Wire would either be trenched some inches, or run under landscape stone.
    – puppycrack
    Commented May 14, 2020 at 20:15
  • 1
    Yeah, having mains voltage cross over into low voltage wiring systems is a serious worry for NFPA, and it can happen when either wire overheats and melts for instance. Stuff goes wrong, and you don't want a single point of failure. That's why the compartmentalization rules are so strict. Commented May 14, 2020 at 20:15

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