Wiring – Please clarify wiring to and for remote pool load center

subpanelwiring

I am replacing an old remote mechanical timer power box for a swimming pool with a new "Pentair Easytouch 4 Load Center with circuit breaker sub-panel".

Background:

  • 200A Main Panel (Sylvania – home built in 1984). Main Panel has two bus bars
    (running vertically on the left and right sides inside the panel); however,
    each bar has both bare copper and Green insulated wires attached to it.

  • Power is supplied to the old pool equipment power box by THREE wires from
    the Main panel, run in a conduit: A Black & a Red hot wire, each connected
    to one of the two screws on a double pole (30A/30A) breaker in the Main
    Panel, plus a single Green wire connected to the right-side bus bar (among
    several other green & bare wires attached to that same bar).

  • At the pool equipment location, there is a copper ground rod previously
    driven into the earth from which a 12 ga. uninsulated copper wire runs
    to and through (and secured at) a lug on the bottom of the old power box
    and then that wire continues on to connect to the ground screw of the
    pump, and then to a ground lug on the bottom of the power supply for
    a Salt Water Chlorine Generator (this power supply will go away, too).

  • Inside the old power box, there is a single bus bar into which is inserted
    BOTH (a) a bare copper wire running from the power box lug (through which
    the earth ground wire passes) and (b) the green insulated wire from the
    Main Panel. [From other posts about service panels, I understand this
    configuration is incorrect]

  • An illustration in the instructions for the new load center anticipates
    FOUR wires coming "From Main Panel" (identified as L1, L2, N, GND). This
    illustration shows L1 and L2 each going to separate connectors on the
    sub-panel, GND attached at the "Ground Bar Bus", and N attached to a
    separate Neutral bus.

  • Then, on that same page, the text instructions say "For the AC supply . . .
    from the main circuit breaker at the house, use three conductors, one each
    for red, black, and white (or red, red and black for 240 VAC)." [As noted,
    we have red, black and green here]

  • The instructions also say the new Load Center ". . . is rated for 150 AMP
    maximum Single Phase (3 conductor)". [The 30 Amp breaker already in the
    Main Panel is less than 150 Amp, so I assume continuing to use it shouldn't
    be a problem until/unless more capacity is required down the road]

Now, my principal question: Do I simply treat the green insulate wire from the
Main Panel as the N (neutral) wire, connect it to the "Neutral Bar" in the new
Load Center and then connect the bare wire from the local ground rod to the
"Ground Bar Bus" in the Load Center? If not, how do I wire this?

Thanks

EDIT/ADDITIONAL INFORMATION:

  1. The conduit is grey 3/4" i.d. PVC and runs from the Main Panel to a junction box just below the old pool power box.

  2. At the Main Panel:

    • Each of the Black & Red wires is 10 ga. (they are connected to
      a double-throw 30A/30A breaker).

    • The Green wire is 12 ga. (connected to the same bus bar
      as are most of the bare wires in the panel [ground bar]).

  3. Also in that conduit are one 14 ga. Black wire and one 14 ga. White wire.

    • The 14 ga. Black wire is connected to a single 15A breaker in the panel.

    • The 14 ga. White wire is connected to the second bus bar in the panel
      (along with all of the panel's other White wires and a couple of the
      bare ground wires [neutral bar]. (Should I move those bare wires to
      the other bus bar?)

  4. In the Junction Box at the other end of the conduit:

    • The 10 ga. Black and Red wires are connected to the "Line" side
      of a single throw on/off switch and a jumper from the Green 12 ga.
      wire is connected to the ground screw of that switch. Additional
      10 ga. Black and Red wires run from the "Load" side of that switch
      up into the old equipment power box (switch is local power cutoff).

    • The 14 ga. Black and White wires are connected to the "Line" side
      of a GFCI outlet and a jumper from the Green 12 ga. wire is
      connected to the ground screw of that GFCI outlet. Additional 14 ga.
      Purple and White wires run from the "Load" side of the GFCI outlet
      into another PVC conduit along with a Green 14 ga. jumper from the
      Green 12 ga. wire. The 14 ga. Purple and White wires from
      the "Load" side of the GFCI are connected to the "Line" side of a
      second single throw on/off switch and the Green 12 ga. wire is
      connected to the ground screw of that switch. Additional 14 ga.
      Purple and White wires are connected to the "Load" side of that
      second switch and, together with another 14 ga. green wire connected
      to the ground screw of that switch, run through another PVC conduit
      to power the pool light.

NOW –

From the comments, I understand I must end up with one more (White) conductor coming from the Main Panel to this new Load Center. However, because the new Load Center also serves as a sub-panel, it seems like it might be a good idea to pull those 14 ga. wires out of the conduit, move the 15A breaker into the New Load Center, and then connect the GFCI/pool light wiring to the 15A breaker in the New Load Center. At the very least, it seems like that would free up one space in my already crowded Main Panel and provide a bit more room in the conduit.

I do have a 100' fish tape (this run is about 75'), but the above makes me think of two more things:

  1. If I simply add one 10 ga. White wire, will the two 14 ga. wires I remove be strong enough to pull that new White wire through the conduit at the same time?

  2. I believe the present 30A/240V power from the Main panel will be enough for now. But in a few years we may add water features or other powered amenities that would require more power. So, would it make any sense to pull ALL of the existing wires out of the conduit now and replace them with a single cable containing larger ga. wires (three 8 ga. or 6 ga. conductors and a ground), leaving only a breaker change to be done at the Main panel if needed later? (I'm guessing that, with the heavier cable here, I wouldn't be able to pull such a new cable through by tying it to the old wires being removed, could I?)

Thanks,
Paul

Best Answer

Neutral is not ground. Connecting a white wire to ground may seem like a "neat hack wrapped up in a bow", but it is out of the question. (You would be wiring a pool like an obsolete NEMA 10 dryer connection, which is just asking for an electrical drowning.)

By the way, the color codes for ground are green, yellow/green or bare. They are all the same thing, and all such wires should be connected together.

To start with, given the price they want for this thing, you should be able to consult the factory and ask them how to connect a 240V-only supply, which is what you have. The subpanel appears to be a mere convenience and it looks like the guts of the machine run on low voltage. It could be as easy as changing (or even rejumpering!) a transformer.

Your wiring is in conduit!

That makes this a simple matter. Get enough strong light nylon rope to cover the distance and then some. Pull all 3 wires off the panel and splice it to the rope overlapping by about a foot. I recommend splicint 1 wire to the rope then adding the other 2 wires to the bundle with another layer of tape.

Then push the wires through carefully (so they don't whip around and contact something in the panel) and once they're clear, go to the other end and pull, pull, pull! This replaces the wires in the conduit with the rope.

If the pulling is difficult, it means there is a pulling point (junction box, conduit body) somewhere in between. Those are there to make pulling easier. Find each pulling point and work backwards.

Once the wires are all the way out and replaced by the rope, carefully inspect each wire's insulation for any damage. Any you find, add it to the list of wires to buy.

Then go out and buy a white wire of that same length + 3 feet, and any other wire colors needed. Ground must be green or bare. Neutral must be white or gray. Hots can be any other colors, and they can be the same color.

Then add white (and whatever other wires you may be replacing) to the wire bundle, and use the rope to pull it back through.

Hook it up as you found it, plus neutral to the neutral bar.

The neutral bar maybe the same as the ground bar in this panel, but still, Neutral is not ground anywhere else.

If you were not in conduit...

Or you can obtain a 7.5 KVA 480/240V/120V transformer and derive neutral locally. That is a complicated setup, so price those transformers of size 7.5 KVA or larger, and if that's agreeable ask us how to do it.

The simple fact is that you are installing an entirely new device with entirely new requirements. The existing line was installed to support a pool pump, and that's all. Reuse of a line like this is hit-and-miss. The right answer is run a new cable.

Also, regardless, since this is a pool and you are upgrading a single circuit to a subpanel, you will need appropriate grounding rods. The grounding rods are an addition to, not a substitute for, a ground wire. Dirt is a poor conductor. If you try to carry fault current with dirt, you get voltage gradients that kill anyone not standing on one leg.

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