Pool light - Subpanel problem.


Old 04-12-05, 07:10 AM
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Pool light - Subpanel problem.

What is the correct/safest way to wire a 500 watt 120v wet niche pool light?

Here's what I have done so far...

Pool light wiring comes out of the ground through conduit.

Need to connect this to an outdoor sub-panel, which will be fed from a main panel inside the house.

Currently, I have a 50 amp GFCI double pole breaker feeding the subpanel with #6 wire.

The subpanel has a 20 amp single pole GFCI breaker that the light is connected to.

The light has two grounds, one is going to a grounding rod and the other is going to the subpanel bus.

A ground wire also connects the sub panel to the main panel.

When I try and turn on the 20 amp GFCI breaker in the subpanel box, it kicks the 50 amp GFCI breaker at the main panel.

What have I done wrong?

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Old 04-12-05, 08:03 AM
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Do you have the ground and the neutral properly isolated in the sub panel?
Old 04-12-05, 08:17 AM
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Location: welland ontario
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That two ground wires doesn't sound correct. Are you sure one of them is not a nutral. A ground rod at the pool doesn't sound right either.
What happens of you disconnect the new light and turn on the breaker?
Old 04-12-05, 09:20 AM
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Just a question as an aside to this thread:

Does having a GFCI breaker at the main panel and a GFCI at the subpanel provide any extra protection? Wouldn't everything in the subpanel already have GFCI protection?
Old 04-12-05, 09:55 AM
Join Date: Jun 2004
Location: Ontario, Canada
Posts: 96
The electrical code associated with swimming pools is fairly exacting. (and varies from region to region)

I looked into this a few years ago, when I installed my pool. Around here (Ontario, Canada) the code gets really picky if you have any electrical outlet or light within 3 m (10 feet) of the edge of the pool. I came to the conclusion that I would not go down that road, so I went with low voltage pool lights, and I am happy I did.

Is it too late to return your light and go with a low voltage one? The installation is much easily, and I think, safer. For example, since my sub-panel is more than 3 m away from the pool in a structure (garden shed) not directly accessible from the pool enclosure, I did not need to bond all the metal objects together (pool shell, pool fence, pool steps, etc). If I had installed high voltage lights in the pool enclosure, this and several other requirements would have kicked in.

However, getting back to your problem. Why do you need to protect the light circuit with a CFI? The sub-panel is already protected. However, that should not be cause the 50 amp breaker to trip. Have you tried removing the 20 amp CFI?

Not sure I have been much help. Sorry.

Last edited by impeyr; 04-12-05 at 12:58 PM.
Old 04-12-05, 04:28 PM
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Ground rod? There should be NO ground rod for a pool light.
Do you have the proper deck box installed? (680.23(B) & 680.24)
Is the second ground the one required due to the use of PVC conduit from the forming shell? This is not a ground but a bond. It only goes to the deck box and that's it. If so is it correctly potted in the forming shell?

If I may suggest, I would get an electrician who is very familiar with pools to come in an check all your work. Pools have very specific and complicated codes. Many licensed electricians I know do not even know pools all that well. It's the "If you don't do it you forget" rule. Many guys go years without ever doing a pool.
If anything I would get a very comprehensive book covering pool codes to help you along. This is not an area you want to get something wrong.
I also hope you plan to get everything inspected when you are done. You will not have a C of O on your house unless you do.
Old 04-12-05, 04:51 PM
Join Date: Jan 2004
Location: Oregon
Posts: 1,219
I strongly second Speedy's suggestion.

The rules for pools are exacting to the point of mandating the depth of the light fixtures, and you have to be very picky about properly bonding _all_ metal in the pool, including the ladders and the rebar. Get this wrong, the _grounding_ itself could be dangerous, picking up stray current flowing in the ground and concentrating it to dangerous levels. (Hyperbole note: the worst case that I am suggesting is very far fetched.)

I am guessing that your light has a ground for the actual light itself, and another for the metal shell. Both of these need to be bonded to the pool equipotential grid. See article 680 of the NEC.


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