Green, orange, white wires from 1950's house - which is what?

publickmanSeptember 19, 2011

My house was built in 1950 - originally about 850 square feet, but it was expanded to almost double in 1995. The wiring in the old part of the house is still pretty much what it was in 1950, and in the old master bedroom, the wires for the ceiling fixture are white, green, and orange. When my brother and I tried to install a new ceiling fan, we noticed that the two green wires had been taped off and were not being used. With the circuit breaker on, but the switch off, the green wires have 115 volts running through them when tested with either the white or orange wires. The white and green wires (the ones that were connected to the previous fixture) have no current when the switch is off but have 115 volts when the switch is on. We think that the white is hot and that the orange is neutral but are not sure - it could be the other way around.

What should be do with the green wires? Do they pose a danger? We got the fan to work but have not been successful with the light unit. I am going to check the wire connections this evening, if DB has enough energy left.

BTW, we have one circuit breaker that apparently does not turn anything at all off, and it is in the old part of the circuit box. Is this normal? The previous owner did a lot of his own work, and he did a terrible job of installing the previous ceiling fan. He used a wood screw instead of a machine screw to hold the fixture to the J box, and we had to retap the hole in order to replace that with a machine screw. The heater in the attic makes access to the J box from above very difficult, and it would be extremely difficult to replace the ceiling mounting box anyway, but at least it is very solidly in place.

Can anyone explain the standard wiring for houses built before 1959? I'm particularly concerned about the green wires.


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First, who knows what others may have done in the past? Are you referring to the premises wiring (done by an electrician who comes to the house) or the wires that are part of a light fixture (installed at the factory by the manufacturer)? Is your house wired in conduit?

    Bookmark   September 19, 2011 at 1:21PM
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I am referring to the premises wiring - from the ceiling we have one white wire, two orange (connected together), and two green (connected together). We had an electrician repair an outlet in the living room that was on the same circuit and it had not been properly grounded, causing the cable guy to get a shock when he tried to install our TV cable.

I do not know whether the house is wired in conduit - how do I figure that out? I went into the attic to try to look at the ceiling mounting box from above, but the heater was in the way. If necessary, I can get around that, but it will not be easy.

Thanks for your response!


    Bookmark   September 19, 2011 at 2:01PM
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Look in the ceiling box back into whatever is carrying the wires.

Chicago is one of the only places that requires all conduit, but that does not mean there are not smaller places that may have required it, or that it has not been used.

Use an extension cord in a correctly grounded receptacle to get a ground to check out the wires in the box.

    Bookmark   September 19, 2011 at 2:12PM
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Conduit on the 1950's was a metal pipe. Non-metallic cable had either a smooth plastic outer covering or a braided fabric outer covering. No cable listed for Type NM that I have ever seen has the combination of White, Orange and Green. That plus the fact that that there is only one white leads me to believe that this is conduit. The combination of colors you list could meet code requirements if all are properly connected. If your wiring is cable, it is unlikely that it ever met code specifications.

    Bookmark   September 19, 2011 at 2:26PM
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The ceiling box has metal conduit coming out of it carrying the wires, but I do not know how far it goes. BTW, the house is in Los Angeles. My neighborhood (Westchester) was built mainly for workers at the Hughes Aircraft plant, and most of the houses were built from 1947 to 1952 - mine was built in 1950.

Good idea about the extension cord for ground wire, but how do I know if a receptacle is grounded correctly? Some in the living room on the same circuit were not, but perhaps the ones in the bedroom were done correctly. When we had a home inspection before buying the house, the only problem outlets were the ones in the living room that we had repaired, and so I assume that the ones in the bedroom are okay.

I was unable to find out any information about orange wires, but I will test them again with the extension cord.


    Bookmark   September 19, 2011 at 5:39PM
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Fabric covered red wires, of that vintage,
will now appear orange.

    Bookmark   September 20, 2011 at 9:51AM
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"but how do I know if a receptacle is grounded correctly?"

Use an outlet tester.

While they can give wrong results sometimes, if they indicate the wiring is correct they are almost always correect.

It is the error cases they can mess up on.

    Bookmark   September 20, 2011 at 9:58AM
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Ron Natalie

An outlet tester will give you an idea if the ground pin is connected to something approximating ground potential. It won't tell you squat about if it is grounded CORRECTLY.

    Bookmark   September 20, 2011 at 1:47PM
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For using a volt meter the currents are so small that ground potential if more than adequate.

    Bookmark   September 20, 2011 at 5:52PM
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Regarding fabric covered individual conductors, I never saw those in branch circuit residential wiring after WWII. And we did a few in EMT. Thermoplastic became the norm. Thermoplastic would have been used in the 1950's. The fabric was really rubber with the fabric outer wrap. The 1959 NEC lists T, TW, THW, and TA as thermoplastic types. Other thermoplastic types were for fixture and switchboard wiring.

    Bookmark   September 20, 2011 at 7:00PM
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The woven fabric was used over rubber insulation that only came in one color, black.

The fabric was never the only insulation.

    Bookmark   September 21, 2011 at 9:59AM
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The insulation is plastic, no fabric. I have been measuring the voltages using a digital multimeter.

Here is a link that might be useful: Multimeter

    Bookmark   September 22, 2011 at 10:56PM
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