Wiring terminology definitions & why you shouldn't use the safety ground for a Neutral connection

Home wire definitions:

Newer homes:

  • Black wire = Line = Power
  • White wire = Neutral = return
  • Green or bare wire = Safety ground.

Older Homes:

  • Black wire = Line = Power
  • White wire = Neutral = return
  • Metal box and metal armored cable = Safety ground.

The “Line” is considered the wire the power comes from. It is typically 120VAC when measured to the neutral wire and 120 VAC when measured to the safety Ground.

The “Neutral” is wire the power goes out to. It is typically 0 volts relative to the safety ground.

The line and neutral are the wires needed to light a bulb or power a fan etc.

The “Safety Ground”, sometimes called “Equipment Ground” is a feature to protect the user and their family from deadly shocks.

When wiring a smart dimmer situations arise where the location you wish to install the device does not have a neutral wire. There is a strong temptation to use the safety ground in place of the missing neutral. This is not recommended (actually prohibited by law) and can bring unforeseen consequences if something else fails.

When considering using the safety ground in lieu of a neutral I believe people may only be considering the “normal” or 100% working case. The issue here is the danger that can arise when something else goes wrong or is wrong.

I’m not an electrician by trade, but when I was younger I worked summers for an electrician. In doing so I learned the basics. Since then I’ve only performed work on my house or for friends and relatives. Nothing major, only swapping out switches, receptacles, installing GFI’s etc. With this small exposure to house wiring I’ve seen:

  • Line and neutral reversed.

  • Receptacles strung in series where one wire is intermittent causing seemingly weird results when a light is turned or off.

  • Generally not so good connections.

I’ve personally had a good quality electric fry pan short out internally and was saved from potential risk by a GFI

Also consider the equipment ground was first introduced in the 40’s. It was recognized back then that a non-current carrying ground was required to keep users safe. So don’t think you know more than all those folks that preceded us just because you cannot readily see “…but why not…”

Finally, in the works of Buford T. Justice (aka Jackie Gleason) “… you can think about it, but dooon’t do it…”