Faulty flourescent lighting balasts

[TractorLegend]

I have a bunch of those energy efficient four tube flourescent fixtures at my shop with the skinny tubes. Some of them were there already and some I bought frome Home Depot.
All the ones I bought from Depot have gone out one at a time. They have you assemble them yourself, so i'm wondering about if theres a way to miswire the balast. It's got vague directions. So on the burnt out ones I went back to Depot and got just the replacement balasts (Advance brand, replacing sylvania) I hook all the wires with butt splices color to color. Are these just not reliable fixtures or any ideas??
The bulbs are pretty fresh too.

 

[Bully]

Sounds like you might have a wire in the but connector crimped, but not making any connection /forums/images/graemlins/confused.gif I have always had good luck with the heavy ballast. The lights I have trouble with, are the 4' shop lights with the cheep transistorized unit on the side. Maybe you can check the connections with an ohm meter, with power off. check the bulb ends, and the little spring steel sockets that the bulbs fit into, the yellow on one side and red & blue on the other just push into the bottom of the socket, and not making the connections. Bully

 

[Soundguy]

I've had the same problem with those cheapy 4' all in one lamp units. And no place to drop in a replacement ballast.. event he small ones. I'm not sure if 7.99$ is a good deal or not for a lamp that lasts a year then you have to change the fixture /forums/images/graemlins/shocked.gif

Soundguy

 

[TractorLegend]

my fixtures are the ones with four- four foot skinny tubes each fixture, (f32T8) so the overall length is eight feet and the balast is a replaceable rectangle box type. I dont think its the splices because they pass a pull apart test.
The two that went out yesterday were during some connecting new wiring to the junction box they are wired in so power was interrupted on the neutral side intermittently for a spell.

 

[kennyd]

</font><font color="blue" class="small">( The two that went out yesterday were during some connecting new wiring to the junction box they are wired in so power was interrupted on the neutral side intermittently for a spell. )</font>

Do this test:
Disconnect that neutral again, and test the voltage on the hot leg to ground.

There is a chance you will see 220V /forums/images/graemlins/shocked.gif, not 120v as you would expect! If so, I will explian in further detail...

 

[kennyd]

Mark asked me to elaborate in a PM, So I thought I would post here instead for all to read:

Why 220 Volts when there should be 120 Volts?

Here is the best way I can explain it:

This problem usually occurs when two separate circuits are fed with one 3 conductor (w/ground) cable, i.e. 14/3 and 12/3. This is usually done in lighting circuits where you take a 14/3 cable to a ceiling mounted box and switch one leg for the lights (usually the black wire), but leave the other (usually the red) hot all the time for a fan or outlet. In this setup, both hot legs share a common neutral wire (the white wire), and this is perfectly fine IF it is hooked up in the panel the PROPER way.

What happens is this:
If the black and red wire a hooked to breakers on opposing busses, then when the neutral is opened, the devices or appliances on those two circuits will see 220 volts across them, usually doing some damage obviously! If you look at a EL panel with all the breakers removed, you will see that the copper buss that the breaker contacts is different for every other breaker, so breaker #1 and breaker #3 are on different “phases” or busses, as are breaker #2 and Breaker #4.
Does this make sense so far? So, a common mistake by DIY’ers and even some electricians is hook up the black and red on say breakers #1 and #3 (one on top of the other), so if you hooked a meter up across the black and red, you will see 220 volts (think about it…that’s how you hook up a 200 volt circuit isn’t it?) So when the neutral is opened, 220 volts can be present at the devices!

Still with me?

The solution is simple, just move one breaker so that the two hot legs (black and red) are on the same buss (phase), so that when you put a meter across the two hot legs, you will read 0 volts. This would basically be one even numbered and one odd numbered breaker.

This is hard to explain by typing, and I hope I was clear in my exploitation. If all this confuses /forums/images/graemlins/confused.gif you please do not stick your hands in the EL panel and get killed and say it was my fault! /forums/images/graemlins/crazy.gif

 

[midlf]

Hooking up a 3 wire circuit, two hots and one neutral to two breakers on the same bus is in violation of code. The reason is the neutral could then carry the sum of the current on the two breakers. So for #12 wire and 20 amp breakers the neutral could carry 40 amps. In your fan/light example both the black and the red would have to be fed from the same breaker if you did not want to have the 120/240 supply.

 

[Inspector507]

midlf is correct, that is a code violation, at least with the NEC®. And it could cause a fire due to overloading the neutral in that multi-wire branch circuit. Code requires them to be on opposite phases for a reason.

 

[TractorLegend]

Truly great knowledge i would have never considered...code or not. Thanks all!!

 

[Ray2210]

Funny. One of our offices at work has a couple of Home Depot fixtures with electronic ballasts and one of the fixturres just toasted a balast. We were just commenting how it would be nice on what should be a long life balast if it would at least outlast the first set of tubes. It was about a year old.