Inground Pool Electrical Safety

Inground Pool Electrical Safety

The CPSC has reported 14 deaths from electrocution in swimming pools during 2003-2014. The cause can be faulty pool light wiring, improper bonding or grounding of equipment, failed Ground Fault Circuit Interrupters (GFCI), or dropping power tools in the pool.

Let’s take a look at each of these possibilities, and if something seems amiss in your pool electrical safety, have a certified electrician check it out. Many electrical hazards around the pool are often created by over-zealous homeowners and pool service techs; call an electrician.

Inground Pool Electrical Safety: Underwater Pool Lights

Pool lights are naturally seen as the most obvious risk area for pool electrocution, being a light that’s underwater. When Calder Sloan, a 7 yr old Florida boy, was fatally shocked by a pool light in 2014, there was a great debate over whether 120V pool lights should be banned. But the Sloan pool had low voltage, 12V lighting, which can also be unsafe when mis-wired, and when GFCI’s fail to interrupt the circuit.

pool lights

The light cord wires run in conduit (pipe) from the back of the light niche, to the junction box where the wires connect to the wires coming from the GFCI breaker. The junction box should be 18″ above the water level, to keep pool water out. Both ground wires from the light and breaker are connected together and pig-tailed to a green ground screw inside the J-box.

An electrician should ground the light niche, to protect against any stray voltage. Inside the wet niche there is a grounding lug that must have a bare copper wire connected to it, normally this a continuous ground around the entire pool. An electrical potting compound is put over the grounding connection, the termination encapsulated in a wet niche potting compound. This helps protect the connection from the possible deterioration from water and chemicals.

Underwater pool lights eventually fail. After about 30 years, the cord casing and lamp housing begin to corrode. Older lights or modified pool lights often lead to hazardous situations. Never make repairs to the pool light cord, or splice an underwater light cord. There are no pool light parts available for the cord or housing, only bulbs, gaskets, lenses and clamp assemblies. Always use the correct replacement bulb, and replace with a new lens gasket.

If you are concerned about your pool light safety, call an electrician to come have a look. A few hundred dollars spent is a cheap insurance policy against pool electrical accidents.

Inground Pool Electrical Safety: Bonding & Grounding

pool electrical grounding

Bonding and grounding are often misunderstood terms, but essentially, grounding is running a green ground wire from the breaker panel, to the green ground screw on the electrical load, such as a pump, pool light, spa blower, electrical outlet or pool heater. All of the ground wires go back to the breaker panel and attach to the ground, which is connected to a buried grounding rod.

Bonding on the other hand, is a continuous loop of bare #8 copper wire, that connects all of the metal equipment and components of the pool. Your pump motor, heater, blower, lights, and also your pool ladders, diving board or slide, steel in the pool shell and in the pool deck.

Bonding lugs are used to connect the continuous bare wire to the pool walls (1), the plumbing (2), pump, heater, skimmer, ladders and handrails (3), and the mesh steel in the deck (4). Image by Burndy.com, maker of specialized bonding lugs for the industry.

Inground Pool Electrical Safety: Ground Fault Circuit Interrupters

The pool light must be installed on a GFCI circuit. That means that the wires coming to the pool light J-box must come from a GFCI breaker. These are often easy to spot by the yellow Test button, and are usually 20 amp breakers.

Ground Fault Circuit Interrupters

Often the same circuit is used to power a GFCI electrical outlet underneath the pool sub panel. The outlet serves as secondary protection to the breaker, both will trip if they sense a voltage variance, or voltage going to ground.

Both GFI breakers and outlets can, and will eventually fail. I recommend having an electrician replace GFCI breakers and outlets used on a pool – every 30 years. You should also test them regularly, by pushing the Test button, to be sure it quickly interrupts the circuit.

Power in the Pool

Sadly, a few electrical accidents around pools are not the result of faulty pool electrical wiring, but from radios, power drills, hair dryers or other electrical items, plugged in and dropped into the pool. Rechargeable tools and radios are the safer alternative. If an appliance is dropped into the pool, a GFCI outlet should shut off the power in 1/4 second, but if not, unplug the power cord first! Do not dive in after your expensive device, or attempt to pull someone who is being shocked to safety, unplug the cord or shut off the power.

You should know where and how to shut off power to the pool. Most inground pools have a 100 amp sub-panel installed by the pool pump and filter. This is a small breaker box with a flip-up lid. The large breakers are for pumps and blowers, smaller breakers are for lights and outlets. Flipping the circuit breakers to the off position will shut everything off, but power is still being supplied to the breaker box, from a large 100 amp breaker installed in the main house panel.

Be alert for other electrical hazards around the pool, like overhead power lines, which can be contacted with a metal pool pole. Missing protective panels or covers on time clocks and breaker boxes can also be hazardous. Cracked and broken wire conduit powering pumps, lights and heaters can cause wire casings to split, exposing live wires.

Be careful around your pool, and call an electrician if anything looks fishy!

20 thoughts on “Inground Pool Electrical Safety

  1. Paul McGowan

    Hi, I am replacing a very old pool light and switching from Halogen to LED.
    The wet niche is properly grounded as is the light itself to a Pentair Junction Box.
    My question is in regards to the Screw that holds the ring of the light to the wet niche. It’s not there due to the old niche not having a spot to screw the ring to.
    Is it necessary for the ring to be bonded to the niche or not since the light and niche are both grounded?
    (I will need to use some sort of Silicone to hold the new light to the niche as a result)

    • Paul, the niche is bonded, but not the lamp itself. There is a product called Light Wedge that fixes the problem of a broken light niche screw hole, at 12 o’clock. I don’t see it on our (new) website yet, but if you called, 800-288-7946, you could ask for item ZAPC5316, Pool Light Wedge, $13.

  2. Jack Hormozi

    Hi Ichanged my GFCI pool outlet and after instaling I noticed even when I shut it off my pool light can be on what could be the problem

    • Hi Jack, most lights have a separate light switch, usually near the GFCI, under the sub-panel, but sometimes they place it next to the house, or perhaps a secondary switch near the back door, inside.

  3. Lew Hodgett

    Can you provide the Article 680 paragraph number that contains the requirement for a dedicated circuit for the pool light? I looked at Article 680 in my copy of the 2014 NEC and didn’t find it. Perhaps it’s a more recent requirement?

    • Hi Lew, I don’t have a copy of the Article, I believe you must pay $$ for that, Article 680.23 deals with underwater lights (luminaires), and refers to a branch-circuit for the underwater lighting. This means that the pool light is on its own breaker, and if over 15V, must be GFCI protected. If the light niche is metallic, it must be bonded to the grid, or the bonding wire. They do not mention that the pool light must be on an “Individual Branch Circuit” (aka dedicated circuit), with no other loads connected, which is why you often will see the GFCI outlet underneath the pool sub-panel, also connected to the pool light GFCI breaker, in the sub-panel. So, my read is that a pool light must be on a dedicated breaker, I may have mis-spoke saying dedicated circuit. However, your local inspector is free to interpret the NEC differently.

  4. Hello,
    My city pool recently added a spraying feature to the vacuum they have always used and I noticed it was not connected to a gfci outlet.
    I mentioned this to them and they shut the vacuum off but informed me they have always ran the vacuum without a gfci.
    The person also mentioned that the pump house has lots of water inside of it.
    I’m very concerned and mentioned that people could be electrocuted and this is very bad but also the persons responsible could go to jail.
    She said they have insurance.
    Am I wrong believing that liability could include jail time?
    Please let me know and thank you for your reply

    • Hi Rick, in cases of gross negligence, as determined by a court/jury, the possibility for jail time exists, but perhaps more possible would be a lawsuit for monetary damages, against the city and possibly city employees found to be grossly negligent. IT is harder to sue a governmental body than say, an apartment building or a pool service company, because there is a bit of ‘municipal immunity’ but if the evidence of gross negligence is proven and without a doubt, a jury may award a judgement against a city. I’m not a lawyer by the way, and I’m not sure a GFCI is needed or useful, this is just a general observation.

      • Thanks Davy,
        Are gfi’s required for pumps by NEC 680?

        • yes, The National Electric Code requires that all swimming pool pumps be connected to a GFCI breaker.

  5. Curtis Crowell

    My concrete pool is approaching 29 years or so. The stainless steel lamp housing (120v) got wet and moisture entered below the resin base that includes the bulb socket as well as an embedded thermal breaker. The socket contacts have some corrosion so I figured I will just replace the entire lamp housing, as the GFCI trips when the circuit is turned on.

    Does the line just pass back through the niche and up the conduit to the junction box? No frost damage issue, or silocone sealant that would prevent water from freezing inside the conduit (I live in NJ).

    When the pool installer first closed the pool they lowered the lamp to the bottom with a weight, then later they stopped doing that saying it was not needed. I have closed it myself for 15+ years and also stopped lowering the light with a weight.

    • Hi Curtis, yes the cord passes thru the hole in the back of the light niche and runs to the junction box. I normally cut off the cord on the back of the existing lamp and strip off the cord casing, wind the old wires and new wires together, wrap very tightly in a few layers of duct tape in different diagonal directions, and then with power off of course, open the junction box and disconnect the old light cable and start pulling the new cord thru, by pulling out the old cord. First stretch out the lamp to the shallow end and remove the coils in the cable, and it may help to have a helper helping to push the cable into the conduit, while you pull on the other end. Pull the new cable thru, but leave 4-5 ft so the lamp can be pulled up on deck later for service. Then cut off the excess cord at the junction box and wire the power leads to the light cable as before. Yes, no need to weight down the lamps for winter, that is very old school. The idea was to prevent ice from cracking the lens, which just doesnt happen.

  6. Shannon tisdel

    Hi there, we recently had a under water pool light replaced in our in ground pool, it never worked when we bought the place, our pool guys when pulling in the new found that at some point org was cut in half,there was a 12gauge green ground wire traveling with it and assuming it was cut also they never hooked it back up,I guess is that it was grounding the niche, my question is how safe are we swimming in the pool with only the light itself being grounded to GFI and breaker?

    • Most pools are like you have it, well most older pools, the newer codes have the additional bonding wire, connecting the light niche with that 12 ga wire. I think you may be safe, but if you want to wire it to code, they could certainly run a new wire.

  7. Joel Jordan

    We are renting a house and the pool light went out. The leasing agent sent out an electrician that said he couldn’t pull the existing wire through the conduit so he spliced the new light to the old cord. Then applied some kind of bonding agent on the splice, which will always be underwater. Is this against code? He did install a GFCI but those could fail after time correct?

    • Hi Joel, I don’t believe that is allowable, per code, but if done properly, by a licensed electrician, I would assume (?) it is safe. Adding the GFCI was good.

  8. Question: Is it acceptable to run an electric line from pool light junction box three feet to an electric panel (using the panel for any additionally needed breakers and such), and from that panel to power led lights in a shed that is about 10 feet away from pool??

    • Answer: No, not at all! That is definitely not in compliance with Article 680 of the NEC, and should be terminated. The pool light circuit must be a dedicated circuit.

  9. anthony Bachelier

    I installed a rebuilt pool motor & now it will not turn on,I have tested the timer & the switches & the Gfci with a voltmeter & iam getting power from circuit,iam stumped & cannot figure this out! Plz Help

    • Hi Anthony, are you getting power to the motor? You can test with your voltmeter leads placed directly on the motor terminals, where the wires connect (with power turned on of course). If not, one of the wires could be split, or loose connections on the ends. If there is power, is it correct for the motor? Many motors have reversible voltage, and can be switched from 220V to 110V. Look at the voltage diagram on the motor label, and compare it to the set-up on the terminal board. If all is correct, check the capacitor, it may have discharged power and need replacement. Also check the centrifugal switch on the rear of the shaft, to be sure it is tight, and aligns with the stationary switch, the triangular switch screwed in at 6 o-clock.

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