The 2011 National Electrical Code required a neutral in every switch box to accommodate new devices like motion sensors, occupancy sensors, home automation switches, and dimmers. If your switch box doesn’t have a neutral wire, find a device that doesn’t require a neutral or have the box rewired by a professional electrician. White and gray wires are normally used as neutral conductors. Don’t make this mistake. If you see a ground wire connected to a current-carrying screw or terminal on a switch or outlet or to a white, black, or any other color wire, stop immediately and call an electrician to sort it out.
Still, many older homes don’t have neutral wires, and some inexperienced do-it-yourselfers will connect the white neutral wire from a new switch to the ground conductor to make do. Photo: Green, green with a yellow stripe, and bare copper wires can only be used for grounding purposes.Ī ground wire can never be used as a neutral, even though it connects to the same bus at the main panel-that’s a huge safety violation that can cause electrical shock, serious injury, or death. That’s allowed by code as long as the wire is marked with red or orange tape or paint to alert future service people, electricians, or knowledgeable do-it-yourselfers that the wire is not a neutral but rather a current-carrying conductor.
Since those appliances don’t require a neutral but use two current-carrying conductors and a ground wire, an electrician may repurpose the white to carry the secondary phase (also called a “secondary leg”) of the 220-voltage. However, when sized appropriately for the load, two-wire armored cables can also be used to provide power to 220-volt appliances like a water heater or well pump, which is where things get tricky. The hot or “live” conductor sheathed in black typically carries power to a 110-volt light or receptacle, while a neutral conductor would carry energy away and a bare copper ground wire can conduct any excess energy that might otherwise be a shock or fire hazard.
In this case, your water heater is probably wired with two-wire flexible armor-clad “BX” or “MC” cable-that’s a factory-made cable with a metal jacket protecting a black, white, and bare copper wire. A: You’re right, white sheathing does generally indicate a neutral wire, but it’s not always so simple to decipher.
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