V asked in Home & GardenMaintenance & Repairs · 9 years ago

Is it code to use a neutral from a nearby outlet on a different circuit to install a timer on a light switch?

The timer requires a neutral wire and will control a light fixture. The existing light switch box has only the black hot wire coming from the light fixture. It is not feasible to change the cable coming from the light. There is an outlet near by to which I can connect a cable and run a neutral wire. The light is on a 15 amp breaker and the outlet is 20 amp. Thanks


The light fixture has its own neutral. The way these timers are manufactured, there is a black, a blue, a neutral and a ground wire. The black is attached to the line, the blue to the load. Therefore the light fixture wiring in essence is unchanged. The additional neutral is for the timer itself only. At least that's the way I read it. I've asked the question to two NJ electricians and they indicate they don't see any code issues. At this point it's academic. But I am very curious. Any National Electric Code references would be welcome. On a different note: I always thought mixed wiring on the same circuit was not code until someone referenced the code and indicated it's ok as long as the breaker matches the smallest wire, e.g. #12 & #14 on the same circuit with a 15 amp breaker.

10 Answers

  • Irv S
    Lv 7
    9 years ago
    Best Answer

    Not to Code, .... but it's done.

    Each circuit is only supposed to be connected to it's own neutral.

    They, (the neutrals), all tie together at the main panel.

    What you propose could interfere with a GFI of AFCI breaker or device.

    Source(s): Retired Electrical Consultant
  • 9 years ago

    If the 20 and 15 amp circuits are connected to the same phase and the 20 amp circuit should happen to lose it's neutral connection at the neutral bar, then the added cable of the 15 amp circuit's connecting neutral would be required to carry the load of both circuits. No, this is not allowed.

  • KMA
    Lv 6
    9 years ago

    IF you are wanting to control a coach light by the front door or eve mounted security lights, get an Intermatic programmable wall switch/timer.

    No neutral required.

    DO keep the instructions handy as they are a bear to reprogram by memory!

    Other than that they work very well.

    What ever you do, don't run a wire exposed. Don't run a single wire by itself.

    You don't want to have a safety issue or something you have to remove should you put the house on the market.

    Source(s): a Licensed Electricain
  • Jeff D
    Lv 7
    9 years ago

    I'm pretty sure it's not code and it's definitely dangerous. The neutral on the other circuit is sized for that circuit, not for both. In a worst-case scenario you could overload the neutral and start a fire. There's also a problem when someone goes to work on the other circuit. They flip the breaker thinking it's now safe to work on that circuit but it's not safe--there's still power running through the neutral from the other circuit!

    I'd sooner connect it to a ground wire than another neutral, but I'd probably just fish a wire.

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  • Danny
    Lv 4
    9 years ago

    I would bet if you look a little better you'll find the white neutral wire pinned back out of the way. It sounds like a typical light switch that you’re replacing with and electronic timer. I don’t believe the builder’s electrician would have run a special single black wire to the switch he’d run a regular wire bundle and just pin back the natural. ? ? ?

  • Labman
    Lv 7
    9 years ago

    How many contacts does the timer have? Can you power it off the outlet circuit and switch the light circuit?

    Could you replace the switch with a relay with the coil powered by the timer? You can even buy little ''starters'' meant for heavier loads that fit in a switch box. They have a coil and contacts. AB makes them and likely others.

    Source(s): I have seen blowers wired up that way.
  • 9 years ago

    You may have the wrong type of timer since you have a loop switch (only hot wire) i believe you need one that has only two terminals

  • 9 years ago

    While I'm pretty sure that's not up to code specifications, it might work ok. There are alot of code spec's which are absolutely necessary, then there are those which can be fudged occasionally without any damage to anything or anyone.

    Source(s): 40 + years of home building, remodeling, repairing and maint.
  • ALAN
    Lv 4
    9 years ago

    yes, unless the wire is a different size,as in smaller.

    Old houses often routed the neutrals around in a separate kind of circuit.

  • 9 years ago

    Although it will work, there is no electrical or building code that allows this.

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