Ground wire for shop lights

[eric dunkelberger]

I have one hardwired 8' fl light for my shop and need more lights. I bought 6 new t8 fixtures. I planned on using the existing 15amp 120v wires that fed the existing light. It is now a 3way switch with the light at the end. I discovered that the wires have no ground. the house was built in the 50's and it could be original. Do I have any recourse at this point other than to replace the wires back to the panel with grounded wire? Tearing out the walls and installing new wiring was not part of my plan. I only know the basics of electrical work. I could use some suggestions. If i have to rip it out, then that i what I will have to do, but I wanted to see if there were any other options before I did so.

Eric

[Jamie Buxton]

Do the existing wires get to the fixture inside conduit? If so, the conduit is likely ground.

[Lee Schierer]

Code does not allow you to run a separate ground wire. I think your choices are use the circuit as it or run new wiring.

[eric dunkelberger]

Do the existing wires get to the fixture inside conduit? If so, the conduit is likely ground.

No, it is not a conduit. Just standard NM wiring in a wall.

[eric dunkelberger]

Code does not allow you to run a separate ground wire. I think your choices are use the circuit as it or run new wiring.

Lee - I wasn't suggesting adding a grounding wire.

So if I leave it as is, is having no ground to the lights a deal breaker? From the reading I have done, I never got a clear picture of the risk of having no ground. I need a cost benefit analysis of continuing to use the no grounded wires with the expanded lights vs the costs of installing new.

[Phil Thien]

Code does not allow you to run a separate ground wire. I think your choices are use the circuit as it or run new wiring.

This is the correct answer. If it is at all possible, I'd pull a new cable.

[Dan Hintz]

I never got a clear picture of the risk of having no ground. I need a cost benefit analysis of continuing to use the no grounded wires with the expanded lights vs the costs of installing new.

Cost analysis? Your death... high enough cost?

If the metal covering on your lights ever shorts to line, you can quickly become a short to ground when you brush up against it. With no ground wire, the breaker doesn't pop until a lot of power has surged through your body.

[Jamie Buxton]

Code does not allow you to run a separate ground wire. I think your choices are use the circuit as it or run new wiring.

Hunh? The existing wiring has no ground. If he adds a separate ground, it may not meet code, but it is safer than using the existing wiring.

[Duane Meadows]

I'd put the circuit on a gfci breaker. The chance of that not tripping with any fault is slim to none. Any current goes any where but back the neutral... that circuit is dead! And yes, I know it would not meet code that way either!

[Lon Crosby]

Have been told that adding a GFCI to a two wire system meets national code. The outlets affected must be labeled. Easiest way to increase electrical safety in an old house. GFCI's work independently of ground.

[Dan Friedrichs]

I don't think you need to replace the wire. I believe you can just wire up the hot and neutral lines and leave the ground on the fixture disconnected. Certainly no one expects that a house be rewired upon replacement of a light fixture.

In terms of the cost/benefit analysis: As Dan H. said, if some part of the fixture failed which caused the hot wire to short to the metal chassis of the fixture, you could touch this and be electrified. That said, such a failure is somewhat unlikely, and given that this isn't an appliance that you will be touching while in use (I assume it mounts to the ceiling, and you'd switch the power off before touching it to change bulbs), there's really very little risk. The risk posed by using a "3-to-2" plug adapter on an appliance is likely much greater than the risk posed by this fixture.

That said, make sure the wire is the appropriate size for the load you're connecting, and if the wire is aluminum, be sure to read about the various risks and precautions specific to that situation.

[John Lifer]

There is absolutely No reason to run new wire. For those of you who question this, go walk through your house. See how many of your appliances are only Two wires with No ground. Same issue with possibly of internal failure. And no I wouldn't change a light to gcfi.

[Dennis Ford]

If the light fixtures are such that you could touch their metal case; I would add a GFCI breaker (assuming that one is available for the possibly old panel).

[Jamie Buxton]

There is absolutely No reason to run new wire. For those of you who question this, go walk through your house. See how many of your appliances are only Two wires with No ground. ...

Unless they're old -- like fifty years --- appliances which are two wire no ground have plastic exteriors, not metal.

[Dan Hintz]

There is absolutely No reason to run new wire. For those of you who question this, go walk through your house. See how many of your appliances are only Two wires with No ground. Same issue with possibly of internal failure. And no I wouldn't change a light to gcfi.

This is horrible advice because it's based upon incomplete information. The two-prong plugs are double-insulated, i.e., if something internal shorts out, there is still a layer of protection between the user and the electrified stuff (like a plastic case). Old drills, for example, had durable metal cases... but man, when one shorted out, you had best not be holding onto that drill. Wall warts (power supplies) are double-insulated, hence they can get away with no grounding prong.

[Steve Milito]

One issue not mentioned, if these are ceiling mounted fluorescent lights, is that some modern fluorescent lights need a ground plane to ignite.

[Rod Sheridan]

I have one hardwired 8' fl light for my shop and need more lights. I bought 6 new t8 fixtures. I planned on using the existing 15amp 120v wires that fed the existing light. It is now a 3way switch with the light at the end. I discovered that the wires have no ground. the house was built in the 50's and it could be original. Do I have any recourse at this point other than to replace the wires back to the panel with grounded wire? Tearing out the walls and installing new wiring was not part of my plan. I only know the basics of electrical work. I could use some suggestions. If i have to rip it out, then that i what I will have to do, but I wanted to see if there were any other options before I did so.

Eric

Hi Eric, check with your local electrical inspector, they are very helpful.

They will probably allow you to run a ground wire to a suitable ground, such as a water pipe, or to a grounded electrical box.

It is important to have the ground wire, both for personal safety, and to make sure that the flourescent lamps work properly...........Regards, Rod.

[Phil Thien]

In terms of the cost/benefit analysis: As Dan H. said, if some part of the fixture failed which caused the hot wire to short to the metal chassis of the fixture, you could touch this and be electrified. That said, such a failure is somewhat unlikely, and given that this isn't an appliance that you will be touching while in use (I assume it mounts to the ceiling, and you'd switch the power off before touching it to change bulbs), there's really very little risk. The risk posed by using a "3-to-2" plug adapter on an appliance is likely much greater than the risk posed by this fixture.


I don't disagree w/ anything you've said.

And yet my sister was electrocuted by a light fixture when she was carrying a long piece of conductive metal (an antenna, in her case).

IMHO, the OP should run a new cable, or add the GFCI breaker. Do one, or the other. But I wouldn't just leave the ground hanging.

I'm not a fanatic, but when we're doing electrical work, we have the perfect opportunity to visit these safety issues and pick-off the no-brainers. That GFCI solution seems like a no-brainer to me.

[eric dunkelberger]

One issue not mentioned, if these are ceiling mounted fluorescent lights, is that some modern fluorescent lights need a ground plane to ignite.

they are ceiling mounted fluorescent lights. I didn't know this was an issue for them to ignite.

Eric

[Steve Milito]

Some of the one's with reflectors need to have the reflector grounded, which makes it act as a ground plane.
It depends on the design.
http://www.science-bbs.com/69-electronics-design/fb127e1d404764c9.htm#.Uik-fsaTh8E

[Dan Friedrichs]

I think replacement of the light fixture is really a separate issue from the wire. Replacing the fixture makes the situation neither more safe nor more dangerous - the fixture doesn't change anything. So if the OP is OK with living with ungrounded cable, he can go ahead and replace the fixture and he won't have changed any aspect of the system's safety.

That said, I'd probably pull new wire, if it were my house. BUT - I understand that re-wiring a house is a major project (time and money), so I'd probably prioritize replacing wires on circuits that see more direct-user contact. The light fixtures on the ceiling are not a high priority, if the rest of the house is wired without grounds.

[Ken Tucker]

Also Eric check your total amp draw you say that you are installing 6 fixtures on 1- 15 amp braker and you already have a 8'er on this circit . I never let the load exceede more than 75% of the breakers size.should be around 11.25 amps on a 15 amp brkr . if all fixtures are going to come on at the same time . check start up amps . anyway a dead short is going to take the path of least restants wheather human or copprer.you pick, dont go with odds it wont ,go with odds it will.only when. run a ground or gfi . you only need 1 or 2 gfi outlets $$$ is not much. and easest. gfi= go for it .lol.

[Jim Neeley]

There's another consideration here: if you have all of your lights on one breaker and for some reason the breaker trips, you are in the dark (although your power saw may still be spinning). If you split your lighting between two or more breakers, all of the power must go out to lose all of the light, which will also kill the power to the tool (saw).

Just a consideration.

Jim

[Mike Cutler]

Eric

I'm a little late, but have a question. Are you absolutely certain that your house has no grounding scheme? This has been a code requirement for decades, and decades.
The "standard", if you will, was to pull the NM wire to the box, metal, and terminate the ground to the box. Also at that time separate "ground bus" wiring was tied to all boxes, sometimes on the back. It's possible to see both, depending on when the house was built.
All of your boxes should have a ground and the grounds should tie back to the panel, and terminate with the neutral returns under the bonding bar. This is what would allow a current GFCI, post 1978 code, to work with an older system. No ground, No GFCI.
Provided that your actual box has the ground, the only section of wire that you would need to replace is the section from the switch to the fixture, and tie in a ground.
I really think that you are in need of an electrician at this point to determine, where, what, and if, you have a grounding scheme. It could save you a lot of time and money.
I do not know if you have pulled your main panel front plate, and I don't recommend it unless you really know what you are doing, but if you have there should be bare copper wire, or maybe a green sheathed wire tied to the white ones. Each NM termination may not have it's own ground, there may be just one or two that "daisy chained to the boxes".
Older house wiring can be a little difficult at times. I've seen fuse protected knob and tube, still in service, with wiring upgrades through the years that included sub panels ,all still in use in the same house. Split systems, Edison wiring, you name it.

As for your current light replacement; If it/they came with the provision to tie in a ground, and I'm sure they did. You should/need to use it. Whether for safety, correct operation, or code compliance, it should be used.
Ground is always your friend.;)