White wire taped black


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Old 01-06-15, 02:35 PM
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White wire taped black

I have an end-of-the-run duplex receptacle that I'd like to change to a switch/receptacle combo. But the white wire is taped black. I've read about taping the white wire black to indicate that it is powered, but can't figure out why it is so designated in this case. Can anyone help? (House is old construction (40s or 50s, all DYI, I think). Thanks!
 
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Old 01-06-15, 03:09 PM
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Welcome to the forums.

You currently have a receptacle in a box. You want to remove it and install a switch receptacle combo. Will the switch just control that receptacle ?
 
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Old 01-06-15, 03:34 PM
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It would be strange to have a black and a taped black on an end of run receptacle. Are these the only wires in the box?
 
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Old 01-06-15, 07:05 PM
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What is the voltage entering the box?
 
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Old 01-06-15, 07:13 PM
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Good point Joe, I didn't even consider that this might be 240 volts.
 
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Old 01-06-15, 07:18 PM
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I doubt a duplex receptacle would be 240v. We'll need to get confirmation from the OP.
 
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Old 01-06-15, 07:25 PM
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I doubt a duplex receptacle would be 240v. We'll need to get confirmation from the OP.
But, I have seen it.
 
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Old 01-06-15, 08:45 PM
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Yes, just one cable comes in, with a black wire and a white wire (no ground).
 
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Old 01-06-15, 08:48 PM
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I don't have a voltage tester. Both sockets in the duplex receptacle work fine. I'm assuming the voltage is 120.
 
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Old 01-06-15, 08:52 PM
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The switch will control a wall light that I want to install. Currently, a corded wall light is plugged into the top of the duplex receptacle.
 
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Old 01-06-15, 09:41 PM
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Just unusual to see a white wire remarked for no reason.

The only problem when installing a combo switch/receptacle is that the receptacle is a three prong grounded type that can only be installed where there is actually a ground present.

I'm assuming a metal box here. Can you look into the back of the box and see what type of cable you have. It could be two wire BX (metal armor) or a two wire NM (cloth covered cable).
 
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Old 01-07-15, 03:24 AM
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Could it be that the wire is taped because of a repair, possibly from a previous loose connection or frayed insulation in older wire?
 
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Old 01-07-15, 06:21 AM
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The only problem when installing a combo switch/receptacle is that the receptacle is a three prong grounded type that can only be installed where there is actually a ground present.
This can be made legal by installing GFCI protection either by a GFCI breaker or installing a GFCI device ahead of this last box.
 
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Old 01-07-15, 09:05 AM
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Yes, it's a metal box. The cable seems to be cloth rather than metal, although it's really hard (from age?), and it isn't coiled the way BX is (at least from the photos I looked at online).
 
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Old 01-07-15, 09:14 AM
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I looked at the taped wire (took the tape off), and there doesn't seem to be any damage to its sheathing. I'm wondering if the receptacle was once a switch (it's at the height of a switch on the wall). If that were the case, would it be logical to tape the white wire? Maybe when converting it to a duplex receptacle, they didn't bother to remove the tape.
 
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Old 01-07-15, 09:41 AM
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I think you're right choc,
Even in the 50's, a room without ceiling fixtures would have a switched receptacle (1/2 switched).
It sounds like somewhere along the way, this single cable was a switch loop for a receptacle and was reconfigured to deliver constant power to the switch box and a receptacle was added.
You should invest in a cheap meter though just to verify you have 120V between black and white.
Also, in the 50's, the box may be grounded from behind. If you see a machine screw at back of box with nothing attached, this is probably a screw and nut securing a ground to back of box, inside wall.
 
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Old 01-07-15, 10:11 AM
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Many thanks! I appreciate everyone who took the time to answer, and I will invest in a meter!
 
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Old 01-07-15, 10:29 AM
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Just a suggestion. You may want to rethink your adding a plug in light. The configuration you have now is one of the easiest to convert to ceiling fixtures.
You have a power source.
You have a cable running from power source to switch box.
It a simple matter of running only one cable into ceiling, this cable can be from either switch or receptacle, whichever is easier. Whichever route you take, the wiring can be made to work.
 
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Old 01-07-15, 11:06 AM
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I want to change the corded wall light to a wall light controlled by a switch (getting into the wall with a cable would be easier in this situation than getting into the ceiling), but need to keep one half of the receptacle as a "plug-in" outlet because there are no others in the room.
 
 

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