I recently replaced an old 2 tube 48 in. fluorescent lighting fixture in my kitchen that's ballast had gone bad. I mounted the new 48 in T8 fixture and wired it up with the wires coming from the ceiling like the old one. I installed the old one probably 20 year ago and it worked fine. When I turned on the switch the breaker tripped! .I checked the wiring with a volt meter and its getting 120 volts .from the black and white neutral.

. When I disconnect the bare ground wire it didn't trip the breaker. I turned of the power and used a continuity tester to check between the Black and ground wire and the White neutral and ground. When I checked the Black Hot and the bare grounding wire the test didn't lite up. When I tested the White hot neutral to the bare grounding wire the test light lite up!.. I don't know if the ballast on the light is bad and is the problem or if I have a ground fault in the wiring! I don't know if the continuity tester should light up and show continuity with the White wire and the grounding wire. I don't think it should but I'm not certain. When I turned on the switch to the light with out the grounding wire attached to the light it didn't trip the breaker. I would appreciate some advise or what may be the problem, the ballast or the light wiring, and what to do to correct it. The old light worked fine with the wiring. I've installed a lot of electrical things without any problems but I'm getting old and not as sharp as I once was. I don't know if I pierced a wire on one of the mounting lag screws I used..

One was the old hole and the other I had to drill a new hole. Suggestions pleas as what to do! I was told by where I bought it it could be the ballast and I could bring the light back but want to make sure what the problem is first.

 

The light lit when you touched the white and ground wires because they are effectively connect together in the panel.

Reconnect the light as normal. Sometimes a breaker will trip when reset even with no overload. Also inspect all the exposed wires. There may be some damaged insulation someplace that is shorting to ground.

 

How tight did you tighten the cable clamp? I have seen tightened too much and they shorted the wires.

 

I'm going to wire up the fixture again and turn it on and see if it trips again. I didn't over tighten the cable clamps. I checked the Black hot wire to bare ground wire and there's no contact between the two. So I guess its not shorting out. If it trips the breaker I'm taking it back and trying another one to make sure the ballast or wiring on this one isn't shorting out for some reason. They said I could return it. I appreciate you guys replying with your advice. I'll try again and see what happens and get back to you.

 

You could always do a test of installing a receptacle or simple light socket.

 

Too late now but you could have just installed LED tubes that do not use the ballast.

 

I did what you said rewired the light fixture and turned it on and it didn't trip the breaker. Put the blubs in turned on the switch and the light is working fine for now. Thank you for quick response and help from you and the rest of the members. Hopefully it will run OK . Im glad I did want rewire the house wiring. I saw the lED lights but didn't know what kind of light they give off. Happy with this one.