Pool Light Cord Too Short? How to Pick the Right Length (Pentair MicroBrite 620425 vs 620426)
A pool light cord that comes up short is one of the most annoying problems in this business. The light itself is fine. The install is fine. But the cord won't reach the junction box, and now the whole job is stuck. We hear about it every week.
That's why Pentair sells the MicroBrite in more than one cord length. The 620425 comes with a 100 ft cord and the 620426 comes with a 150 ft cord. Same light, different cord. This guide covers how to measure your run so you order the right one, and what to do if you're stuck between the two.
What's the difference between the Pentair 620425 and 620426?
Cord length. That's it. The Pentair 620425 is the MicroBrite color LED light with a 100 ft cord, and the 620426 is the same MicroBrite color LED light with a 150 ft cord. The fixture, the color modes, and the low-voltage design are the same on both.
So this isn't really a question of which light is better. It's a question of how far your light niche is from your junction box. Measure that, and the choice makes itself.
How do you measure how much pool light cord you need?
Add up the full path the cord has to travel, not the straight-line distance across your yard. The cord runs from the light niche, through the conduit buried behind the pool wall, all the way to the junction box. Then you need slack on top of that.
- Start at the niche and estimate the conduit run to the junction box. If you're replacing an old light, pull the old cord out and measure it. That's the most reliable number you'll get.
- Add enough slack to set the light up on the deck for service. The standard practice is enough extra cord to lift the fixture out of the niche and rest it on the deck, so nobody has to work on it in the water.
- Add a few more feet for the connections inside the junction box.
If your total lands anywhere near 100 ft, don't gamble. Go up to the 150 ft Pentair 620426. A cord that's a little long is a minor thing. A cord that's a little short means the light won't pass inspection, or won't connect at all.
Can you extend a pool light cord that's too short?
Not inside the conduit, no. Splicing a cord in the conduit or behind the niche is a safety problem and it's not allowed under electrical code. Any connection has to happen in the junction box, and if the cord can't reach the junction box in one continuous run, it's the wrong cord.
This is the mistake that costs people money. They buy the 100 ft light for a 110 ft run, figure they'll deal with it, and end up buying the longer light anyway. If you're not sure your run fits the 620425, spend the extra on the 620426 up front.
What do you do with extra cord?
Coil it neatly behind the light in the niche, or leave the excess at the junction box end. Extra cord stored in the niche is normal and it's actually useful, since it's the slack you'll use to pull the light up onto the deck the next time it needs service.
So don't be afraid of the 150 ft cord on a 100 ft run. Nobody has ever regretted having too much pool light cord. Plenty of people have regretted the opposite.
Which MicroBrite should you buy: 620425 or 620426?
Buy the Pentair 620425 if your measured run, with slack included, comes in comfortably under 100 ft. That covers most residential pools where the junction box sits near the equipment pad a reasonable distance from the pool.
Buy the Pentair 620426 if your run is anywhere close to 100 ft or beyond it, if your equipment pad sits far from the pool, or if you simply can't measure the run and need to be safe. Large yards, long conduit paths, and lights on the far side of the pool are all 150 ft territory.
Both are compatible with the same low-voltage MicroBrite installs, so cord length really is the only call you have to make. Measure once, order once, done.
Not sure this is the right part for your problem? Reach out and we will help you figure out exactly what you need before you spend money on the wrong thing.