Question on Wire?

Inspected a remote distribution panel ( sub- panel) today. This was in a condo, I did not look at the main panel. I counted five wires coming from the main to this panel. The fifth wire is not connected to anything. Could someone tell me what this wire if for and what’s it doing here? I always thought only four wires to sub panel.



When I was an electrician, if I were running wires through a conduit or trace that would be impossible to run at a later time, I would run an extra just in case.
Of course, it may be as simple as a helper running one too many wires by mistake.

Hey david you mentioned it was a condo. Could be the building has 3 phase, and the extra wire was run by the builder not knowing if the units would need it or not. It used to be fairly common to see 3 phase for HVAC in some residential settings.

Maybe a ground or bonding wire that was not needed? I see it here all the time

Thanks for the reply’s guys. There are other problems with this panel. I’ll let the electrician figure it out.

That extra conductor is used for 3 Ø useage and it can be used either 208Y120 v or 240/120Delta { the delta system is very tricky to deal with it }

Most condo I useally run into are normally wired in 3Ø setup unless that box was replaced for some reason and not used the thrid phase at all.

A electrician will able verify it if not hook up or hooked up at the metering centre that is the only way you can able find out.


I am with Larry on this one