On Jan 13, 10:01*am, wrote:
On Sun, 13 Jan 2013 05:57:42 -0600, wrote:
A large store downtown has a heavy FOUR wire triplex feeding the
building. *3 wires are black insulated, the other is the bare neutral.

The thing that caught my attention to it, is that the 4th wire is not
connected to anything. *All the triplex I've ever seen is 3 wire, two
are insulated, one is bare. *That's for a standard 240V single phase
system.

Im thinking that this cable was intended to be for three phase wiring.
Three hot, and the neutral. *Is this right?
Maybe that building once had 3 phase service, or they just had that
cable on hand when they wired it, and used what they had...

That says "3 phase".
Three hots and a neutral.

Did you read the part where he says the "neutral"
is not connected to anything? Sounds like a support
wire to me.



You can verify it by looking at the transformers.
If you see 2, one perhaps bigger than the other, it is 3 phase center
tapped delta. (AKA red leg or wild leg)http://gfretwell.com/electrical/red%...ansformers.jpg

If you see 3 equally sized transformers it is usually 3p wyehttp://gfretwell.com/electrical/3%20p%20wye-wye.jpg