Latest Discussions : Electrical & Lighting


06:33PM | 09/11/05
Member Since: 08/19/02
29 lifetime posts
I have a 150-watt high pressure sodium security light that mysteriously began cycling on and off about a month ago, after about three years of faithful operation.

Thought the photoelectric cell might have gone bad, so I replaced that.

No improvement.

I suppose my next move will be to try a new bulb, but these things are supposed to last much longer than this one's been in service.

Do these things have some kind of ballast or starter that might have gone bad?

Any ideas on what's causing this on/off cycling?


09:14PM | 09/11/05
Member Since: 04/12/05
15 lifetime posts
Yes, these lights have both a ballast and an ignitor (or starter). And this sounds to me like a bad ignitor. If you open up the fixture, the ignitor is probably a black cylinder a little larger than a 35mm film container, with three wire leads (if memory serves correctly, it's been a while).

Good luck!



05:51AM | 09/12/05
Member Since: 05/03/05
79 lifetime posts
One of the tattletale signs of a bad lamp in an HPS fixture is the cycling of the lamp.

Average life of the 150W hps lamp is 24,000 hrs. This is an average! Some last longer, some don't.

If the ignitor goes bad the lamp will not light at all. Same with the ballast. Some of the "cheaper" fixtures have the ignitor as part of the ballast. I have found that sometimes it is more economical to replace the fixture than to do the repairs after replacing a bulb.


06:26AM | 09/12/05
Member Since: 08/19/02
29 lifetime posts
Yeah, I think it's the bulb, whose behavior seems to fit the consensus here and on another board.

The lamp is a Regent from Lowe's. I've had a number of these and they've all performed well.

And actually, the bulb is closer to four years old than three.

Thanks, guys -- appreciate your help.


02:29PM | 02/05/16
1st thing to try from what I read is to change the bulb. It's called end of life cycling and a common occurrence.
If that doesn't fix the problem, hey, you have a spare bulb, money not wasted. Put the old bulb back in and try other more difficult things like transformer or starter or replace the fixture. (wisest choice). Some fixtures might be able to be purchased without the bulb to save some money. I have two of the HPS lights and a spare bulb would be good to have, even for just testing.
This is the common sense approach I am taking.


11:00AM | 01/28/18
Most of what i hear about it is the bulb. Over time, the gas in the bulb can degrade and leak out. you think it may be all the other things, like ballast, transformer, or the ignitor, but pretty much, the bulb won't light if it is one of those things.
I replaced a bulb, and it still went off a couple of times, then has been very steady operation since then. but before that, i fought this thing for years on different sizes of HPS lights. Change the bulb, and get 2 to 3 more years out of it. after that, if the fixture is bad, change the entire thing.
I never get the 20 to 25000 hours they claim, but i can get 10 to 12000 hours. Things are changing. i expect in the next couple of years, these things will become LED. and those will be lasting.


10:20PM | 01/19/21
I am having the same issue but this bulb was just changed and is only a few months old. Can I have gotten a bad bulb???


02:48PM | 01/21/21
Is it possible that the photoelectric cell, that triggers on and off states, is exposed to the light being emitted? - Light turns on in dark is immediately exposed to the light and turns off - over and over again. This is to ask, is it just the positioning of the sensor or that enough of the light is reflecting back to the sensor, somehow, that is causing the problem? I have seen this before with regular flood lighting.


11:51AM | 04/26/21
Light won't turn on.


11:36AM | 07/29/21
I have 5 (count them) lights that do this on and off thing. Here's what I think: whenever the air conditioner (or for that matter, anything that pulls a lot of current) kicks on, the light goes out, and then has to cycle back on. I'm thinking that there is a critical voltage that must be maintained in order for the light to stay on; as soon as that voltage goes down just a little bit, the light goes off. A brand new light usually doesn't do it, but it only takes a couple of weeks before even a new one will start this.


12:07AM | 11/08/21
My security light bulb was a E17 150 watt high pressure sodium bulb. Will a ED17 150 watt bulb work in that light fixture? Not sure what the difference in those bulbs is.

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