I live in Sparks, Nevada and the 2011 National Electrical Code applies to me.

I am installing a new bathroom fan on a separate circuit from the existing bathroom circuit. I want to change the existing light switch's 1-gang junction box to 2-gang to accommodate the new fan switch. However, the existing wiring on the old switch is not up to code (the wires are not long enough to extend 3" outside the box and the sheathing does not extend 1/4" into the box).

Will the inspector require me to bring the existing wiring (which I am not modifying, just putting in a new box in the same place) up to code to add my new switch?

  • Can the existing wiring support 2 switches? If so you can simply change to a dual switch made for a 1-gang box. Changing a simple thing like a switch yoke or built-in appliance is widely viewed as too small a job to justify pulling a permit. Changing a 1-gang box to 2-gang, more of a wobbler. In the latter case you'd need to talk with your AHJ about whether he wants a permit pull and subsequent inspection; they could advise you on the wire length issue at that time. Mar 5, 2017 at 17:14
  • @Harper No, the existing box won't do because I'd have to add two more pairs of conductors to the box, and the box is already too small (not enough volume) for the existing wiring, much less two more pairs.
    – Tim Sweet
    Mar 5, 2017 at 17:16
  • Yeah, you're in permitland then, and this is a question for your AHJ since he'll be doing the final inspection. Mar 5, 2017 at 17:18
  • I have to get a permit anyway for adding the fan, so the inspector will be reviewing my work no matter what. I already have the permit, so my plan is to have the inspection this week and if he wants me to bring it up to code I'll evaluate my options (including putting it all back how it was before).
    – Tim Sweet
    Mar 5, 2017 at 17:19
  • 3
    If the box is fed from above move the new box location up. Code does not specify the height of the boxes.
    – Ed Beal
    Mar 16, 2017 at 16:33

2 Answers 2


Anything you arent modifing falls under the grandfather act. You will need to rerun or make a splice in a box in the attic (where ever it is being fed from) to extend the wire to the switch and fan to bring it up to code. You shouldnt need a permit to install a fan. If you do, it just a waste of 300 bucks

  • Hello, my jurisdiction requires a permit to add any receptacle. The cost is $1 per receptacle so it's not a problem. Thanks for the suggestion.
    – Tim Sweet
    Mar 17, 2017 at 16:37

no nothing has to be code compliant

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