Swimming Pool Blog

10 Steps to Replacing a Pool Light

by Rob Cox, June 28, 2010

10 Steps to Replacing a Pool Light

lighted pool Ladera RanchUnderwater pool lights don't last forever.  Bulbs, Gaskets, Lens are parts in good supply, but eventually the body of the light fixture, the socket or the cord may fail. At this point you will need to replace the entire fixture or pool lamp, as they are sometimes called.

It is likely that since the time you put in your pool, the technology has improved in underwater lighting. Halogen and LED lamps predominate now, and fiber optic lighting has gained a small foothold in the market. Color Changing lamps or bulbs are really popular now as well.

So, if you are replacing your pool light, you can replace like with like, or you can consider some of the energy conserving LED pool lamps, with color changing ability.


But wait! Not all Lamps will fit all light niches. The light niche is the "bucket" in the wall. The width and depth of your light niche will determine which pool light choices are available to you. Consult your favorite pool dealer (hope that it's poolcenter.com!) to match up your light niche to lamps which will fit.

But assuming that you have made the hard choices, decided against all the available options nowadays, determined your voltage and length of cord needed and are now ready to install your new pool light - how is a new pool light installed? 


1. Shut off power at the breaker. It should be a GFCI protected circuit. This is the one with the yellow "test" button. In most areas of the country, pool lights are 120V - so make sure your light circuit is GFCI protected! In Maryland, and a few other states, pool lights are required to be 12V. Make sure you bought the correct voltage pool light! The label on the light should tell you. Or, if you are 12V - you will have a transformer wired into the circuit, in between the breaker and the junction box. There is no need to lower the water level in the pool to change the light.

2. Locate the Junction Box and remove the cover. The junction box, aka J-box, is usually located directly behind the light, at the edge of the pooldeck, at a height of 12" above the water level. If your pool is very old, the j-box may be located IN the deck, at deck level. This is unsafe, and should be brought up to code, by entending the conduit from this box to an above ground arrangement described above. The distance from the J-box to the light niche, plus 4 feet extra, is what determines the length of cord needed when purchasing your light. The extra 4 feet is necessary to allow enough cord to pull the light up on the pool deck for future maintenance.

3. Disconnect the wiring. Green will be grounded. And the hot and neutral lines will be wire nutted together with the pool light cord. Save the wire nuts. Make sure the light cord does not fall down into the conduit as you are working.

4. Pull the existing pool light up on the deck and cut off the cord at the back of the light. Clean and dry the existing cord. Lay the new cord and the old cord end to end and using Duct Tape, secure the existing (old) cord to the end of the new. Use diagonal, overlapping taping, being careful to keep it slender. If too bulky it may get stuck at a turn or connection in the conduit.

If you don't want to cut the cord from the back of the old light, tape a string or fishtape to the end of the cord, at the J-box. Pull the string or tape through the conduit and out of the niche, then tape securely to the end of the new light cord and pull the new cord back through the conduit and up to the J-box.


5. Standing at the junction box, pull up on the cord, hand over hand motion, until the new cord is drawn up through the conduit and out of the J-box. Cut or peel off the duct tape. It helps to pull the new pool light cord out straight, to remove the coil memory of the cord. It also is helpful to have a helper hanging over the edge of the pool, pushing the new cord into the conduit.

If you are having trouble at this point, getting the cord to move through the conduit, the conduit opening at the back of the niche may have been sealed with putty or silicone. This is done in many cases on leaking pools, to fix a leak in the conduit, or to rule out the conduit as a leak source. In this case, you would be advised to lower the water level, so that you can work on removing the packed in putty, or silicone.

6. Cut the new cord to the proper length. Leave just enough cord sticking out into the pool to allow the light to be pulled up on deck. After cutting the cord at the junction box, strip the cord casing down to the base of the j-box. If there is a clamp to secure the cord, tighten this, so the cord does not slip down into the conduit. 

7. Strip the wires of the new cord and wire nut them to the wires coming from your breaker box. Make tight connections and then securely replace the lid to the junction box.

8. Coil the cord behind the new fixture and secure the new lamp into the niche. The usual attachment method is to insert the tab at 6 o'clock and then tighten the screw at 12:00. If your screw tab has broken off, and there is no threaded screw receiver, you can use a Light Wedge to fix this common problem.  

9. Test your light! Important to mention that a pool light turned on without being underwater will quickly overheat, shattering the lens! You are OK to do a quick 1 second test, but left on for 30 seconds or so, and it will literally explode.  

10. Congratulate yourself on saving hundreds of dollars - doing your own pool repairs.

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