diy shop light pulses?

[pretzelb]

OK, this may be better in the lighting forum but let me start here.

I have a 10g tank setup in my garage to experiment with some stuff. I had an old light over the tank but I wanted to try a new light. I had a 30w "shop" light that I bought from Home Depot that I wanted to put over the tank. By shop light I mean the cheap flourenscent white metal lights that you typically put in a workshop. I bought a cord for the fixture so I could plug it into a timer.

Everything seemed fine after I setup it up last night. This morning the light was freaking out and pulsing. It almost looked like an old barber shop pole in that it looked like a streak was circling the bulb from left to right. I was very shocked and immediately disconnected it and put my old 20w back into place. I did plug the shop light back in but it didn't do the pulsing but I didn't want to leave it in my garage alone until I knew what the deal was.

Anyone have an idea of what this might be? The fixture said 30w and I picked up a 30w bulb. The bulb seemed to be seated securely in the sockets. I think the cord I bought was rated for mid sized appliances in a range from 10-25 (going off memory). The cord was pretty basic to install and I made sure to secure everything inside the fixture. It was unused prior to this so I don't think the ballast that came with it could be bad. I'm not sure what to think, but it scared me.

[Sponsors]

[valiko]

30 watt shop light?

The power cord, is it 2 prone pr 3 prone?
You might have to use 3 prone to ground the fixture.

What is the bulb? T-12? T-8?

[pretzelb]

Originally Posted by valiko

30 watt shop light?

The power cord, is it 2 prone pr 3 prone?
You might have to use 3 prone to ground the fixture.

What is the bulb? T-12? T-8?

The cord was 2 prong. I grounded the cord to the light fixture then just connected the black/white wires from the fixture to the corresponding wires on the cord. I'm struggling to remember the bulb type. I searched online and I think this is the description:

For applications that require medium illumination levels and narrow construction. Suitable for general or task lighting such as utility rooms or storage areas. This 3 ft. fluorescent fixture has a 120 volt ballast and uses one 30 watt preheat T12 lamp. The housing is white enamel steel.

Link to Home Depot light fixture

[Hoppy]

Some timers won't work well with magnetic ballast flurorescents. I found that even the digital Intermatic timers have a hard time with them, and they are supposed to be compatible. It looks to me like your timer is causing the problem. Also, that can happen if the light is too cold when you start it. Magnetic ballast fluorescents also have a minimum starting temperature - around 55 degrees F. as I recall, but they start badly at even higher temperatures at times.

[pretzelb]

I'm not sure what I was thinking with my first post. My cord is a 3 prong, which is obvious since I know that I grounded it. It's also definitely a T12.

I was wondering if it could be timer. That's too bad if that is the case. I found a really cheap timer/powerstrip combination at Home Depot and was hoping it could be used for this. I use it on my main tank with it's Coralife and it works well. Also, my testing was done manually so this morning was the first time it was turned on by itself. I'm not sure why that would matter but it could be the problem.

I guess the next question would be to figure out if it's a fire or explosion hazard.

[DarkCobra]

Originally Posted by pretzelb

I'm not sure what I was thinking with my first post. My cord is a 3 prong, which is obvious since I know that I grounded it. It's also definitely a T12.

Whooa.... I was about to freak out on your earlier post, because if you "grounded" the fixture to anything on a two-prong cord, you did something very bad!

It's possible your power strip, timer, or maybe even outlet is not properly connected to ground on the third prong. Try plugging the light directly into the wall. And double-check the ground connection on the fixture.

Originally Posted by pretzelb

I guess the next question would be to figure out if it's a fire or explosion hazard.

Probably not. Improperly grounded fixtures can do this, so can bulbs approaching the end of their lifespan. Never seen or heard of one suffering catastrophic failure as a result.

[pretzelb]

I'll have to double check the ground on the fixture and make sure it didn't come lose (but I'm pretty sure I secured it as well as I could). What's odd is that after I replaced the fixture I tried plugging the troublesome fixture into the power strip and it seemed fine again, just like it did when I first installed it yesterday. This makes me wonder if it has something to do with the timer, but I can't imagine why that would matter.

I will check it out and post back if I find something.

[pretzelb]

I checked the ground and it's secure. I tried to recreate the problem but with no success. I even let the timer trigger and it seemed fine. I don't feel safe hooking it back up yet so I guess I need to babysit it for now or just give up on the idea.

[oceanaqua]

I have 6 shop light running that I got from Home depot and they are doing great, not a problem for 6 months now. I also run it from a timer that I got from HD. No problem so far...I also ground everything, not a problem. Check if the fixture is not defect, and what kind of bulb. I use phillip sunlight..6500K.

[DarkCobra]

It may be some intermittent problem that only shows up at certain temperatures. Or you may never see it again.

I don't think it's a safety hazard. But if it will help you sleep better, you should return the fixture to the store and get another one.

[jpod1977]

I dont know if this will help you but if you live in a colder climite some cheep flourenscent lights have trouble starting in cold weather (its caused buy the cheap balast they use to make them if you take the light in to a room tempture area of the house it will start working again

just a thought...