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The project is to wire a 125-amp sub-panel from the main, approx. 50 feet away to serve a 220v in-ground 1hp pool pump, heat pump, and 120v LED pool light.

Wondering if the following plan will suffice;

  • Exit the main panel with a 2 pole 220-volt, 125-amp breaker.
  • Run 50-feet of #2 aluminum triplex, and #8 insulated ground to the sub-panel location.
  • Install 125-amp main breaker in sub-panel.
  • Install 60-amp 2 pole, 220v GFI breaker serving pool pump; #6 wire.
  • Install 40-amp 2 pole, 220v GFI breaker serving heat pump; #8 wire.
  • Install 15-amp breaker serving GFI protected 120v for LED pool light; #12 wire.

Specific questions;

  1. Can I direct bury the wire, and then enclose in PVC conduit where it goes above ground to enter the panels?
  2. Will the #2 aluminum triplex, with a #8 insulated ground suffice?
  3. Confirming that in the sub-panel, I DO NOT need to bond the neutral and equipment ground.
  4. Is there likely a better way of going about this?

Update The following is the proposed wiring: enter image description here

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    Is this an inground pool or an above ground, Sounds like above ground from the size of the pump, but there are slightly different rules for both so more info is needed to tell you all the details. – Ed Beal Jun 8 '16 at 1:08
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    Are you saying that the LED and transformer are listed for swimming pool use, the LED is listed for use without a grounding conductor, and that the LED fixture operates below the (stringent) low voltage contact limits defined in Article 680? (30V is the maximum for a constant DC supply -- any interruption at a rate between 10 and 200Hz drops this limit to 12.4V DC, though.) – ThreePhaseEel Jun 8 '16 at 2:19
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    @ThreePhaseEel you realize most common low-voltage pool lighting is 12VDC. It's the least of my concerns. I'm no expert on horsepower since I'm not a horse... but 60A at 240V (14400VA) seems an awful, awful lot for a 1 horsepower motor. Is this a combo heater-pump? – Harper Jun 8 '16 at 5:11
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    The full load current of the motors comes from Table 430.248 for single phase motors NOT the nameplate on the motor. – ArchonOSX Jun 8 '16 at 9:25
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    So I got some more information from the pool place, the pump is a Waterway Champion pump; I called that mfg, and they said the 1hp pump draws 7.1 amp at 230v. The heater is an Aqua Comfort 1100 Heat Pump; haven't had any luck getting ahold of anyone in their office. The light is a Savi LED Light. Either way, the 100amp still seems overkill at this point, yeah? – Sivart Jun 8 '16 at 14:51
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I will answer your questions in turn, and then add a few notes at the end -- the code for pools is complex, partly because they are bespoke installations for the most part and partly because of how pool electrical safety evolved over time.

  1. You actually cannot do this -- the wire run must be in conduit as per 680.25(A)(1). You can use Schedule 80 PVC or RTRC-XW for the entire run provided the stub-up is protected from physical damage (i.e. being clobbered with a mower or whatnot -- 4x4 corner posts around the panel should do the trick, as would mounting it in a drained pump room or pit using an outdoor enclosure, provided clear working space is maintained). Otherwise, you're stuck with RMC or IMC (NOT EMT) -- likely red brass to avoid corrosion.
  2. That 125A number is overkill, requiring a 1/0 or 2/0 triplex in Al. I'd recommend instead using individual XHHW-2 Al conductors instead of a triplex (with an 8AWG copper THWN-2 or XHHW-2 wire for the EGC, of course) -- this will be easier to get through the conduit than a triplex, and also isn't liable to short the neutral to ground unexpectedly if you're running it in red brass. (Conductor/subpanel sizing advice is below, if you wish it.)
  3. You are correct -- never bond neutral and ground in a subpanel.
  4. Your overall plan seems sound, provided the subpanel is correctly placed (it cannot be within 5' of the nearest edge of the pool).

Additionally, given the type of pool you are dealing with, there are a few additional points to consider:

  1. You'll need a convenience receptacle somewhere outside 6' but within 20' of the pool -- this can be at the subpanel, attached to the lighting circuit and protected by its GFCI. (While you don't need GFCI protection on a lighting circuit that's feeding listed low-voltage ground-free luminaires -- it's cheap insurance.)
  2. Your branch circuits will need to be run in conduit as well -- either red brass RMC or IMC, or Schedule 80 PVC or RTRC-XW if you wish to use nonmetallic conduit. In any case, you must run an insulated EGC with the branch circuit.
  3. EQUIPOTENTIAL BOND ALL THE THINGS. If it is conductive, not a hot or a neutral, and is within 5' of the pool, don't take a chance -- just hook it up to the equipotential grid. In your case, since your pool is vinyl-lined, you do not need to run the grid under the pool, just as part of the perimeter paving -- 12" O.C. 8AWG bare copper is used for at least 3' beyond the sides of the pool, with cadwelded (i.e. exothermically welded) or otherwise listed connections. You'll also need to hook this grid up to the pool pump motor's ground wire (which is where it'll tie into the electrical system's equipment grounding system -- for a double-insulated pool pump, just run an EGC down to the pump's j-box as normal and tie the equipotential bond wire to it there), and to an underwater equipotential bonding electrode made from corrosion-resistant materials that has a minimum of 9 in^2 of surface area and can't be damaged by pool activity if there is no bonded metal in contact with the pool water. Also, I recommend running another bare wire from the grid to the subpanel itself, directly -- this is insurance against the EGC connection at the pump motor getting undone.

As to that forum that told you not to bond the equipotential grid to the house grounding system, whoever was posting that there is full of baloney, to put it extremely mildly. NEC 680.26(B)(6)(a) explains it most clearly (strong emphasis mine):

(a) Double-Insulated Water Pump Motors. Where a double-insulated water pump motor is installed under the provisions of this rule, a solid 8 AWG copper conductor of sufficient length to make a bonding connection to a replacement motor shall be extended from the bonding grid to an accessible point in the vicinity of the pool pump motor. Where there is no connection between the swimming pool bonding grid and the equipment grounding system for the premises, this bonding conductor shall be connected to the equipment grounding conductor of the motor circuit.

Finally, as to that 125A number, it's hooey -- the pool pump motor is 8FLA@240V as per Table 430.248 and uses a 20A breaker from table 430.52, not the whopping 60A fib that you were told. In fact, that 60A number that they're giving you just for the pump is enough to leave 1200VA (600 per leg) for lighting and convenience receptacle loads after the 10A max load from the pool pump and the 40A number given for the heat pump -- which is well over three times the 180VA/outlet the Code tells you to allocate to general receptacles and outlets that aren't covered by other loads.

With that information in hand, we can run 4 6AWG THWNs for the feeder, just as you propose, and 14AWG for the pool pump as 430.22 specifies a conductor rating of 125% of FLA, or 10A in your case. (You can also use 14AWG for the receptacle/lighting circuit -- nothing says it has to be 20A.)

  • My question is about the pump 2 pole 60amp 1 hp pump,,,, I agree with most of 3phase's info but this needs to be questioned. #2 using aluminum in a pool area is not smart in my opinion. Or any type of ridged conduit would be allowed. – Ed Beal Jun 8 '16 at 3:33
  • Regarding your point 3, and the equipotential bonding; I read somewhere that you were not supposed to run the grid to the EGC? – Sivart Jun 8 '16 at 3:54
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    Where did you read that? The NEC requires all grounding systems on the premises to be bonded together. – ArchonOSX Jun 8 '16 at 9:19
  • I can't remember the exact place, but it was another electrical forum. I also finally found out exactly what the pump was, and called the manufacture; they said that there was an external grounding connector, and an internal circuit grounding connection; the external is for the equipotential bonding grid; he also stated to NOT connect the bonding grid to the EGC. Thoughts? – Sivart Jun 8 '16 at 14:53
  • @Sivart -- just what is the pump manufacturer smoking?! – ThreePhaseEel Jun 8 '16 at 22:58

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