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Forgive me for my crappy drawing :) to make a long story short I just moved into a home and I am taking a look at one of the lighting jobs. I noticed the light switch had no power feeding it and the "neutral" wire was hot. I was a bit confused and worried.

After doing some testing I realized the white "neutral" wire was actually the wire feeding the light switch power. Then the black "hot" wire was the wire giving the light can its power. (See picture).

Is this legal (in terms of electrical code) and is this safe? Is there any cause of concern since the light switch has no neutral wire connected to it?

ElectircHelp

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    In multiconductor cables, white does not connote neutral. Neutral wires must be white but white wires can be re-tasked to be hots. Today's code requires the wires be marked with tape or paint to signify that they have been re-tasked. In conduit, white or gray connotes neutral. Commented Apr 27, 2018 at 23:23
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    A light switch, as shown in the initial question, is simply an in-line device to open or close a circuit. No more, no less, it simply breaks or completes the circuit, no matter the color of wires connected. Commented Oct 24, 2018 at 0:27
  • The reason why a white wire was allowed to be used for hot in a switch loop is that this allowed common non metallic cable with two insulated wires to be used. This cable in 14/2 (or 12/2) + ground with a white and a black colored insulation was the common cable used in residental wiring. Ordinary mechanical switches do not need a neutral, but only hots (line hot and switched hot). Nowadays the code requires a neutral in switch boxes even if it is not used in the original installation. This allows later installation of devices, e.g., some smart switches, which do require a neutral. Commented Feb 8, 2022 at 20:40

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This is fine in an existing setup...

This is the old way a switch loop was done, using the white wire to carry power to the switch and the black wire to carry the switched-hot back to the light. For a dumb light switch, not having neutral at the switch is a nothingburger, so all's well that ends well. There should be electrical tape wrapped around the white wire at each end to reidentify it as a hot, though -- if that's not the case, turn the circuit off at the breaker and add a wrap of black electrical tape around that white wire on each end.

However, new work works differently

In new work, though, this is not to Code. The 2011 NEC added provisions for neutral (what Code calls the grounded conductor vs ground, which Code calls the equipment grounding conductor) at switch locations in 404.2(C) due to the proliferation of advanced "smart" switches, dimmers, timers, and suchnot that need constant power. The alternatives involve returning that constant current through the load (which is incompatible with LED light bulbs and some other loads) or returning it on the equipment grounding system (which is a dirty hack).

(C) Switches Controlling Lighting Loads. The grounded circuit conductor for the controlled lighting circuit shall be provided at the location where switches control lighting loads that are supplied by a grounded general-purpose branch circuit for other than the following:

(1) Where conductors enter the box enclosing the switch through a raceway, provided that the raceway is large enough for all contained conductors, including a grounded conductor

(2) Where the box enclosing the switch is accessible for the installation of an additional or replacement cable without removing finish materials

(3) Where snap switches with integral enclosures comply with 300.15(E)

(4) Where a switch does not serve a habitable room or bathroom

(5) Where multiple switch locations control the same lighting load such that the entire floor area of the room or space is visible from the single or combined switch locations

(6) Where lighting in the area is controlled by automatic means

(7) Where a switch controls a receptacle load

Informational Note: The provision for a (future) grounded conductor is to complete a circuit path for electronic lighting control devices.

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    "grounded conductor" is actually CodeSpeak for "Neutral". The "grounded conductor" does not refer to ground. Ground is called the "equipment grounding conductor". Commented Apr 28, 2018 at 1:46
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If you mean this ....yes it's illegal. You cannot send a live wire constantly to a bulb terminal.

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    Welcome. The diagrams in the question make the situation fairly clear. I can't really see what you're presenting here, but the question has an accepted answer on it already. Please see How to Answer and take the tour.
    – isherwood
    Commented Feb 8, 2022 at 15:47

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