240V 3-phase delta?

[u2slow]

I'm doing some work in a dual-serviced shop. There's the basic 120/240 3-wire single phase "lighting" service. The second service I had assumed to be 120/208 4-wire 3-phase - until I put a meter on it and found 236V between phases and approx 140V to ground. [img]graemlins/hmmm.gif[/img]

Is this a 240V 3-phase delta service?

Are standard 120/208 3-phase wye load centers compatible?

[electric-ed]

This does not sound like a 3 phase, 4 wire delta to me, where the voltage to ground would be approximately 208 volts.

It is most probably an ungrounded 3 phase delta. The voltage to ground is determined by the distributed capacitance in the system conductor insulation, and is usually somewhere around 138 volts (240 divided by 1.732).

This would normally be a 3-wire service, without a neutral conductor.

Ed

<font color="#a62a2a" size="1">[ July 29, 2004 07:55 AM: Message edited by: electric-ed ]</font>