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Replacing switches with new ones and wanting to add a zwave dual-relay while I'm at it. It's a 3 gang box and all are on the same circuit. I have an electronics background, but no electrical experience beyond replacing switches and a couple fixtures. I understand the theory but definitely don't know if this is to code. My brief googling is telling me that it should be switched hot for safety reasons.

The house was built in 1922, but it was remodeled in mid-2000 with upgraded wiring. One of the switches controls the living room light and an outlet. However, I discovered the outlet is not grounded when I took it off, so I guess not ALL the wiring were replaced.

Here are pictures of the gang box. enter image description here enter image description here

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  • You really need to test the wires to see if the white wires are indeed hot. While it would be odd to use white wires as hot, you can't make all your assumptions purely based on the color of the wire.
    – Steven
    Commented Jun 24, 2015 at 20:06

3 Answers 3

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You are right to be concerned about switched neutrals. A dangerous situation.

You can test it by using a non-contact tester similar to this one

non-contact

Turn on the breaker (after making sure no terminals are touching anything metal). Check the wires going to each of the switches. If wired correctly, one of each should be hot. If they are not, you have a switched neutral.

Hot should be labled black, red or blue. White wires are often used for hot on switch loops, but they are supposed to be labeld black with marker, paint or tape.

If you do find a switched neutral, you need to rewire the circuits. This may be a time to call in a pro. 

Images and links are for illustration only, not an endorsement of goods or sources.
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  • Won't a switched neutral also read 120v on one pole?
    – Comintern
    Commented Jun 23, 2015 at 23:48
  • On a non-contact tester, unless the neutral has been swapped onto the hot leg, it does not beep and light, even if it is switched and even if current is flowing.
    – bib
    Commented Jun 24, 2015 at 0:18
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OMG what a mess!!!, you are correct this is a switched neutral situation. the white wires are neutrals and should be tied together with out a switch. the black wires should go to the switches.

a white wire can be used on a light switch or a switched plug... if it is then make sure it is the sire going to the load and not the hot side.

black red blue 'hot' white neutral.

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  • Are you certain there is enough information here to diagnose the problem this way? Switch loops will often use both black and white wires as conductors. You might see different combinations depending on whether power enters the switch box or the light fixture, where it routes from there, etc.
    – Craig Tullis
    Commented Jun 25, 2015 at 4:15
  • absolutely certain this is a switched neutral situation, the neutrals are tied together, per photo with the wire nut on right second photo... and go to the switch, the hot has to be on the other side of the switch making it constantly hot. NOT TO CODE. have seen it all in my 45 years of power wiring this is nothing new in the complete screw up department. this box and probably all of the others need to be un tangled , sorted out and then wired by some one with a BAC less than 0.8.
    – SkipBerne
    Commented Jun 25, 2015 at 12:18
  • "You might see different combinations depending on whether power enters the switch box or the light fixture "... yes there are right code ways to do it and wrong non code ways to do it. ... and I have seen it all.
    – SkipBerne
    Commented Jun 25, 2015 at 13:57
  • BAC less than 0.8--funny. ;-) The electrical code of course doesn't specify which box the power has to be pulled into, and in a "typical" switch loop you'll see a black and a white wire connected to the switch, and if you're pulling power straight through a box containing nothing but switches, all of the neutrals would be appropriately tied together in the box. The photos don't show the light box, and it's conceivable the neutral and hot were swapped all the way back at the panel. Just saying... BUT you're probably right, it does look like it's switching on the neutrals.
    – Craig Tullis
    Commented Jun 25, 2015 at 15:28
  • a 'switch leg' using a 14/12-2 black white is fine as long as the colors are right. technically the black wire is hot and the neutral wire is the load side and until the power is on is at 'ground' and not 'hot'
    – SkipBerne
    Commented Jun 25, 2015 at 15:38
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In addition to all the other comments, I would suspect you have reversed colour code- IOW, the wiring may have been installed using white as hot FROM THE BREAKER BOX.

I knew of a house that was wired switched neutral all over the house BY A LICENSED CONTRACTOR. The woman's son died from this gross violation.

Many licensed contractors hire untrained hourlies. You can't trust them, nor inspectors.

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  • "You can't trust them, nor inspectors" casts an awfully wide net of aspersion. Certainly there are contractors (and inspectors) out there who aren't up to snuff for whatever reason. You'd hope most inspectors are actually competent. An electrician with an apprentice should be checking all of the apprentice's work, and you (the homeowner) should do your own due diligence. But there are plenty of honorable, hard-working contractors and inspectors out there and it isn't remotely accurate, let alone fair, to dismiss them all as "untrustworthy" in one blanket statement.
    – Craig Tullis
    Commented Jun 25, 2015 at 4:14

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