Easy Question on Switchloops

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  #1  
Old 09-07-06, 06:26 AM
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Easy Question on Switchloops

I replaced an old fixture in the hallway last night. This is one of the few fixtures in the house that receives power first before going on to the switch. I wired the new light up exactly the way the old light was wired and it works fine. I was reading up on switchloops this morning and I'm a little concerned because what I'm reading differs from what I did last night.

I have the incoming black (marked with white tape) wire to the light fixture. Black wire from the other light fixture terminal going to the switch. White from the switch back to the light fixture box and connected to the white wire going back to the source.

Is this OK......or is this, in effect, switching the neutral?

Thanks.
 
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  #2  
Old 09-07-06, 06:55 AM
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Unless your house wiring is backwards, you are switching the neutral which is wrong. If the house wiring is backwards that is also wrong.

To fix your mistake, connect the black power wire to the switch loop white wire: Connect the black switch loop wire to the black light wire. Connect the white power wire to the white light wire. Connect all grounds at all locations and ground the switch, the metal boxes and the light.
 
  #3  
Old 09-07-06, 07:21 AM
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Thanks Racraft.

Your comment about the wiring being reversed has me thinking, because it was a registered electrician that set the light fixture up this way.

After the recent house fire, the fixture was removed to replace some wiring. The electrican said not to re-use the fixture, so he installed a temporary one that I just replaced. He replaced the box also and the power feed wire is also new. It was he who put the white shrink tape around the black wire and wired everything this way.

So one of two things is going on:
1. The electrician messed up or
2. My wiring IS reversed.

How can I test the wiring safely?

I have a bulb tester.
 
  #4  
Old 09-07-06, 07:26 AM
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Test the black wire with the ground. Test the white wire with the ground. The hot wire (which SHOULD be the black one) and the ground wire will light the light.

I cannot come up with a reason that an electrician would intentionally miswire this. Either you aren't giving us the entire story or you didn't hire a proper electrician.
 
  #5  
Old 09-07-06, 07:49 AM
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The electricians That we hired were top-notch. It is a small company in Pittsburgh, but they do a ton of work for the city. The inspector said we chose an outstanding company to do the electrical work. The two guys that came out to do the work had 35 years between them. They were really a good bunch of guys and seemed to know exactly what they were doing.

The guy that wired the light grabbed me and showed me the condition of the light fixture and told me there was no way he would put it back in there. He placed a temporary fixture in for me and told me to replace it whenever I could.

When I took the temporary fixture down, I noted all the connections.

The ceiling box (new work box) is new (they were able to replace this because the ceiling was torn down).

The power feed wire is new coming into the box. It was one of the wires that was damaged and was replaced. I know the electricans put the white shrink tape on the black wire because it doesn't come like that.

The wiring to the switch is old.

Also, most of the wiring in and around this area was replaced (back to the new panel) due to the fire, so the polarity shouldn't be reversed, right?

I guess I'll go home and check things out with my bulb tester.
 
  #6  
Old 09-07-06, 11:14 AM
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Even top notch electricans, like me make mistakes..

Call him back and ask him what to do.
 
  #7  
Old 09-07-06, 11:19 AM
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The white tape on a black wire confuses me. You aren't allowed to remark a black wire for use as a neutral (this is why 14-2-2 has two white wires).

You certainly need to either understand why this was done and go from there.
 
  #8  
Old 09-07-06, 12:15 PM
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If you have any interest in home electrical DIYing, invest in a non-contact voltage probe. You can get them for as cheap as $10-12, and they're a great safety double check. You may also want to get an inexpensive digital multimeter, good for diagnosing voltage issues, circuit continuity, etc.

With a non-contact voltage probe, you would only need to take off the coverplate on the switch, and (careful not to touch the terminals with anything conductive, including yourself) 'scan' near each of the terminals. If it's wired right, one of the two terminals should buzz or beep indicating line voltage. Otherwise, you're switching the neutral.

Marking #12 black wire with white tape is not to code, but there are worse things an electrican can do - at least it's marked if it is in fact the neutral. However, the whole setup is fishy, since he's got a black and a white wire at the switch (even if it's old work, it's wrong). Maybe the white is poorly marked with black paint, or some tape fell off... I don't know, it sounds odd.
 
  #9  
Old 09-07-06, 01:34 PM
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I'm going to check things out tonight.

I'll remove the connections from where power comes into the light and check each wire.

Since the metal box is grounded, I can just touch one probe to the black (marked white) wire and the other probe to the box and see if I get a light, right?

And then do the same thing with the white wire (make sure that it doesn't light) just to be sure.
 
  #10  
Old 09-08-06, 06:00 AM
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I pulled the fixture and tested the wires. My wiring is NOT reversed..........the black was hot.

I removed the white tape on the black wire, marked the white wire black, and wired everything up correctly.

Incoming black connected to white (marked black) going to switch. Black from switch going to Black light terminal. White light terminal connected to white wire going back to source.

Thanks for all the help.
 
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