ballasts

[gettingstarted]

Hi all,
I'm a young apprentice, and I have been told that you always want to ground out a florescent fixture to itself. Why is this? Does the ballast make a grounding connection to the fixture by the way it is attached? What will happen if it is not grounded to itself?
Some insight please!

 

[bphgravity]

Re: ballasts

I've never heard of this nor is it a code requirement. Just follow the instructions from the manufacturer on how to ground (bond) the luminaire and you will be fine. The metal to metal contact of the ballast to the fixture housing establishes the effective fault path.

 

[jerryb]

Re: ballasts

Bryan is right on this. No need to do something special, Just make sure that the fixture is bonded to the electrical system. There normally is a green bonding screw inside the fixture housing.

Several years ago I received an electrical shock when I touched a copper water pipe. After a little experimenting I discovered that all the lay-in fixtures were installed with no grounding conductor. The ballast had a small amount of leakage current which transferred to the fixture body and then to the ceiling grid. If I touched any part of the ceiling grid and a water pipe at the same time, I would receive a 120 volt shock. When I installed a jumper from the pipe to the grid, the shock went away. This is just a good example why everything needs to be bonded.

 

[physis]

Re: ballasts

Says something about the difficulty with GFI's too.

 

[iwire]

Re: ballasts

Originally posted by gettingstarted:
Hi all,
I'm a young apprentice, and I have been told that you always want to ground out a florescent fixture to itself. Why is this? Does the ballast make a grounding connection to the fixture by the way it is attached? What will happen if it is not grounded to itself?
Some insight please!

Some of the new electronic ballasts have a terminal marked ground that must be used but this terminal will not ground the fixture body.

So you end up grounding the fixture and the ballast.

The factory usually dose this by installing a jumper from the ballasts grounding terminal to the fixtures body.

 

[jwelectric]

Re: ballasts

Originally posted by gettingstarted:
Hi all,
I'm a young apprentice, and I have been told that you always want to ground out a florescent fixture to itself. Why is this? Does the ballast make a grounding connection to the fixture by the way it is attached? What will happen if it is not grounded to itself?
Some insight please!

Reading those words that are in bold I am thinking that you might be talking about touching the secondary (wires going to the tube) to the fixture case when working on ballast.

Is this what you are talking about?


edited to get codes right

[ August 12, 2005, 11:20 AM: Message edited by: jwelectric ]

 

[LarryFine]

Re: ballasts

Fluorescents start and operate better when nearby a grounded-metal surface. Ballasts are often marked:"Lamps must be mounted within 1/2" of a grounded metal reflector" or something similar.

 

[gettingstarted]

Re: ballasts

JW, I am talking about landing the bare or green grounding wire on the green grounding screw provided on the fixture. I have always been told to make sure to land the EGC in the manner stated above. My question is what will happen if you do not do this? Will the ballast go out prematurely? Will the bulbs go out prematurely?
Or, is that connection solely for protection of a line to case fault?

 

[redfish]

Re: ballasts

I tend to think that the practice of not grounding your equipment would be a bad habit to form. What about the wire the other guy pinched or nicked that is leaking voltage to the frame of the fixture, this might cause an accident, and at the very least, short out your ballast and bulbs.

 

[LarryFine]

Re: ballasts

Originally posted by gettingstarted:
JW, I am talking about landing the bare or green grounding wire on the green grounding screw provided on the fixture. I have always been told to make sure to land the EGC in the manner stated above. My question is what will happen if you do not do this? Will the ballast go out prematurely? Will the bulbs go out prematurely?
Or, is that connection solely for protection of a line to case fault?

The fixture may have a difficult time firing the tube, especially if cold. That's in addition to the fault protection.

Ever had a fluorescent fixture that wouldn't start unless you touch the tube? That's a sign of a missing ground.

 

[marinesgt0411]

Re: ballasts

isn't that kind of like not putting a wire on that obnoxious little green screw on a switch or receptacle?

110.3(B) ya gotta wire it the way it was meant to be wired.

when all else fails read the directions

 

[redfish]

Re: ballasts

Ever had a fluorescent fixture that wouldn't start unless you touch the tube?

Almost like magic.