I know black and white but what is red and yellow?

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Old 07-07-07, 05:01 PM
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I know black and white but what is red and yellow?

All the electrical work I have seen the wires have been black for hot and white for netural and the ground. I was working on a friend's house which was built in 1972 and fouond some wires that are red and yellow in color. there are still black and whites but part of his house has different color wiring. I'm sure they used to be more common but I have no idea which one is which. Please help...thanks
 
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Old 07-07-07, 05:34 PM
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explanaing what they are used for might make it easeir to understand what he has.

Very simply, Nat'l Elect Code color codes are (for the most part, there are a few little oddities not included here)

white or gray=neutral
green or bare=ground
any other color= hot wire.

So, what are the red and yellow being used for?
 
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Old 07-07-07, 06:38 PM
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Originally Posted by nap View Post
So, what are the red and yellow being used for?
To confuse homeowners
 
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Old 07-07-07, 06:39 PM
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Any chance your friend is in the greater Chicago area? Or maybe NYC? Or maybe outside the U.S.?

Note that there are many situations where the white wire is also hot.
 
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Old 07-07-07, 07:23 PM
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Originally Posted by John Nelson View Post
Any chance your friend is in the greater Chicago area? Or maybe NYC? Or maybe outside the U.S.?

Note that there are many situations where the white wire is also hot.
color code requires white to be a neutral. I would have to check to be sure but in the places that a white ends up being used as a hot it is required to be indicated as such.

I don;t do much resi work so NM is a foreign animal to me.

The only place I use a white is when using something like 12/3 SO cord for 3 phase power.
 
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Old 07-07-07, 08:35 PM
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Regardless of the Code, I think he was only warning the OP that, in practice, many whites are used as hots without being recolored as they should.
 
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Old 07-08-07, 06:41 AM
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As already mentioned, any red, yellow, blue, orange, etc. is HOT.

Very common to find red, as most 3 wire NM cable is black/red/white + bare.
This is used for 240 volt circuits, and multiwire circuits.

Yellow is the color which smoke detectors use for their interconnect, so if a building is prewired for interconnected alarms, you might find yellow for that. But it can be any color, and whatever it is, the colors are all hots of some kind.
 
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Old 07-08-07, 06:43 AM
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I checked the wires with a meter. The red is hot and the yellow is netural. After a bit more investigation, I found this to be used in a 3way switch hook-up. This is in South carolina.
 
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Old 07-08-07, 06:59 AM
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What type of meter? How did you determine that the yellow was a neutral? Does it pass through the switches without landing on any of them? Is there no white wire and yellow was used instead? Just making sure, since the wrong color was used. If so, it might be a good idea to put some white tape around it in each box so the next guy won't have to go through what you just did.
 
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Old 07-08-07, 07:29 AM
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I would have to do some reading but I don;t think code allows a wire as described to be remarked as a neutral. Not positive but I believe that is how it is.

Even with that though, I would, as a minimum, mark the wire as mac suggested. In the case of that or nothing, I would prefer that.
 
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Old 07-08-07, 07:55 AM
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I don;t think the yellow is a neutral. I think it part of a three way switch setup and the poster does not know how to properly test...
 
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Old 07-08-07, 08:04 AM
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Probably right there bob.
 
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Old 07-08-07, 09:01 AM
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Well, then how should I test. I got 120 between the red and ground but nothing between yellow and ground and then again, 120 between red and yellow. Afterall, it's not rocket science.
 
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Old 07-08-07, 09:10 AM
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With a switch open (i.e. off) you will read 120 volts between the hot wire and the other wire because you have a complete path back to the panel across the light bulb(s).

If this yellow wire is attached to the switch, it is NOT a neutral wire.
 
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Old 07-08-07, 09:17 AM
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You are right. I guess that's why you're the pro and I'm a novice. I turned the other switch on and now there is juice between yellow and ground as well. I think whoever wired this, just used a yellow instead of black...I'm marking it and leaving it alone. thanks
 
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Old 07-08-07, 10:30 AM
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You don;t need to mark the yellow. It's already properly identified as a hot wire by it's yellow color.
 
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Old 07-08-07, 08:18 PM
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I hung some spot lights today that used a yellow wire with a green stripe as ground. The instructions cleary state it is for grounding, and they are UL listed. That pissed me off so i punched the lowes lady out.


Umm...just kidding ....
 
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Old 07-08-07, 10:48 PM
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Are you sure it wasn't a green wire with a yellow stripe?

This is very common in foreign countries so we see it often on imported fixtures or fixtures that are available for export.
 
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Old 07-09-07, 07:11 AM
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Positive it was yellow with a green stripe.
 
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Old 07-09-07, 09:36 AM
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You also have to be mindful of color fade in the old plastic insulation. Wiring from 1972 is a little too young to be really faded, but old black wires can look brown or red in some cases; and old white wires can look yellow or brown. This is especially true if the wires have been exposed to the elements or are in a box above a light fixture which has been overlamped.
 
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Old 07-09-07, 03:37 PM
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Wink

These were brandy new.
 
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Old 07-15-07, 12:37 PM
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Originally Posted by burkej62 View Post
Positive it was yellow with a green stripe.
So, is a zebra black with white stripes or white with black stripes?


for an equipment ground conductor to be legal it must be bare, green, or green with one or more yellow stripes.(per 250.119)

You need to take all those lights down Burke and mark those EGC's properly.
 
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Old 07-15-07, 08:16 PM
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Even if they were parts of Listed fixtures?
 
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Old 07-16-07, 02:21 AM
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Ya know, that brings to mind a situaation an old friend had. He was doing some work. The hoomeowner was supplying the fixtures. The had ,I think 4 or 5 wires in the fixture. Must have been some dual ballast or 2 circuit lights.

EVERY wire was green. He told the customer he would not put them up.

Believe it or not they DID have a UL sticker on them.

You never win with this stuff.
 
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