Pool light cutting off? Then back on?

Old 08-08-02, 08:33 AM
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Pool light cutting off? Then back on?

In October 2001, we bought a house with a pool. This is our first pool. The pool is 18x36 inground with vinyl liner. We have noticed that if we turn on the pool light, it will stay on for about 20 minutes. It will then cut off. After 10-15 more minutes, it will cut back on. This is a 120V light, not 24V. I believe that it is made by Hayward.
At first, I thought that it might have some sort of thermal overload protection, like some recessed lights have. However, I have spoken to our electrician and to two different "pool technicians". None of them have ever heard of this kind of behavior. That at least tells me that it is unlikely that this is a design feature.

I believe that the previous owners had the pool light replaced last summer.

Any ideas?
Old 08-08-02, 10:05 AM
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What you are describing is exactly how a thermal protector is designed to work. You say that the light is 115 volts, are you saying that there is no box or transformer anywhere on the circuit?
Please tell us how this light is run to the pool and where it gets it's power from. This light MUST be protected by a GFCI.. in fact I would recommend removing the light and replacing it with a light that operates with 12volts. It is expensive to retrofit but, what's a life worth.
For now do not use that light as I believe that there is a problem with it and the thermal protector is working like it's supposed to.
Old 08-08-02, 12:35 PM
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As far as I know, there is no transformer on the circuit. I suppose that it is possible that there is one under the diving board ( where the junction box for the wires from the subpahel are connected to the cord from the light.

The power for the light comes from a subpanel mounted on the back wall of our house. This is at the opposite end of the pool from where the light is. The subpanel is protected by a 30 amp breaker in the main service panel. Within the subpanel are two circuits. The first is a 15 amp gfci breaker protecting the light. The other is a 20 amp 2 pole breaker feeding the main pump and the Polaris pump. This breaker is a gfci breaker. The pumps are direct wired and are wired for 220 volt operation.

From the 15 amp gfci breaker, the wire goes to a light switch in an outdoor box ( cast aluminum ) that is attached to the subpanel via a short piece of pvc conduit. From the switch, the wire goes underground ( in conduit ) uninterrupted ( as far as I know ) to the junction box where it is connected to the light fixture.

I would have guessed that at least one of the pool guys could have said something like "Oh, yeah, those pool lights have a thermal protector that can cause them to shut off.". Howerver, both of them ( I have had two different companies out to do various work on the pool ) acted like they had never heard of anything like that.

I will probably look into the lower voltage lighting options.

Thanks for your input.
Old 08-08-02, 06:47 PM
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Take a tep measure and measure from the top of the water to the top of your underwater light if you have less than 18" then your light is over heating and was installed wrong unless that light was designed for installation with less than 18" of water cover. The water is the coolant for that underwater light from overheating. While the NEC allows 120 volt underwater pool lights to be installed in you pool there are specific rules that apply. You should read those rules that apply in 680 of the NEC concerning underwater lights to ensure that you are meeting the minimum safety standards. I am suspecting that you pool light is not deep enough in the water to cool or you have the wrong light bulb in that underwater light which is just as dangerous.



(5) Location, Wall-Mounted Luminaires (Fixtures). Luminaires (lighting fixtures) mounted in walls shall be installed with the top of the luminaire (fixture) lens not less than 450 mm (18 in.) below the normal water level of the pool, unless the luminaire (lighting
fixture) is listed and identified for use at lesser depths. No luminaire (fixture) shall be installed less than 100 mm (4 in.) below the normal water level of the pool.

Hope this helps

Old 08-08-02, 07:22 PM
Captain Avenger
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Wgoodrich makes a very important point. Although 110volt lights are permitted for inground pools, he recommends you replace it with a low voltage light. This advice is correct.

99.99999% of all of the pool light installations that I have seen are low voltage. Please be careful and consider the information you received here today.

You can probably make the change for less than 100 bucks, isn't that worth the peace of mind?? Just a thought.

The Captain.
Old 08-09-02, 12:35 PM
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Capton Avenger I suspect you mixed my comments with sparkone42's comments. I made no comment at the time concerning advising to switch to low voltage underwater light.

In my are 80 % of the underwater lights are 120 volt rated with dedicated 12 awg 20 amp branch circuit GFI protected with the proper bonding grid sysetem installed.

Only 10% of the underwater lights are 12 volt low voltage rated again using 12 awg 20 amp GFI dedicated branch circuit to serve the low voltage transformer allowed only if that transformer and low voltage light fixture is approved as an underwater pool light.

Now if you are really concerned about safety why not install a fiber optic lighting system to light the pool eliminating any voltage to the underwater light system at all. Then you could create a motorized changing color scheme of the pool lighting and hit optumum safety concerning eliminating voltage to that light altogether yet alumiating the pool under water at the same time.

Just a thought


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