Latest Discussions : Electrical & Lighting

JRhandyman11209

06:30PM | 11/26/07
Member Since: 11/25/07
6 lifetime posts
If anyone knows about the type of wiring used back in the day in NYC when it runs through piping in buildings PLEASE HELP!!!!!!!!!! I'm changing a simple light fixture and coming out of the ceiling connecting to the old fixture is three wires with there ends twisted together into one and a fourth wire by its self. the old fixture had a brown wire connected to the 3 wire group and a blue wire connected to the single ceiling wire. no black, white, or green. how do I find my neutral wire and my ground. and whats the difference between the two? any and all info needed. thanks

TimBonham

12:41PM | 11/27/07
Member Since: 01/09/07
199 lifetime posts
Back then, they didn't always pay much attention to what color wire they were using. And 50 years or so can cause the color of the insulation to change a bit. I've found white wires that had turned brown from years of heat in a light fixture.

One quick check: metal pipe (conduit) was usually continuous back to the main box, and grounded. So you can try using a neon tester between each of those wires and the metal conduit. If you show current from one, that is a hot wire; and the other one is probably a neutral wire. If they both show current flow, all bets are off -- let a pro figure it out!

Billhart

03:16PM | 11/27/07
Member Since: 04/25/05
1915 lifetime posts
Some of the first wiring used the existing gas piping used for gas lights.

No guarantee at all it is grounded.

Also he mentioned 3 wires connected to gether for one side and only one wire on the other.

Maybe we think that there might be some knob and tube wiring where they did not always keep the hot and neutral together. Maybe from another box or even another circuit.

Or switched neutral.

Even a pro should not work on this unless he is a "gray beard" or someone that likes to do detective work and does not assume that anything is done according to current practives and everything is suspect.

JRhandyman11209

06:32PM | 11/27/07
Member Since: 11/25/07
6 lifetime posts
thanks for the advice. It will help me win I go back to finish up. I'm usually pretty good with basic electrical but when I see wires so old that they have paper and cloth insulation I get nervous. and I didn't have my tester on me. thanks again for the help. I really appreciate it.

JRhandyman11209

06:45PM | 11/27/07
Member Since: 11/25/07
6 lifetime posts
thanks for replying and quickly. I always wondered why the wiring was in gas piping. I revieved a lot of advice and I'm a lot more confident. plus when I go back I'll make sure to have my tester on me (oops). I'm pretty good with basic electrical but wires with paper and cloth insulation always make me nervious. and thats mostly what I see here. again thank you and I'm sure I'll have another question soon.

TimBonham

08:25PM | 11/27/07
Member Since: 01/09/07
199 lifetime posts
Wiring was in gas piping because houses in metro areas often were 'plumbed' for gas lighting several years before electricity was distributed. Later the house was converted to electricity. The gas pipes were used because they were already there, and in the right places -- the locations for a gas valve were appropriate for an electric switch, and the gas pipes led from there to the the appropriate location for a light fixture. So it just made sense for them to be reused.

If the old wires make you nervous, and if the pipes are continuous back to the breaker box, it's not that hard a task to pull the old wires out and replace them with modern wires. Mostly just a matter of pulling them thru the pipes.


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