corner grounded system

[sparkyclark]

I'm trying to find some more info on corner grounded delta systems, the company I work for wants to install one and I told them that it's not a very safe system can anyone help?

 

[resistance]

I never deal with delta systems, but from what I read: When installing or grounding a corner grounded delta system, it is best to see it as a single-phase system. If you plan to use circuit breakers--instead of fused switches--make sure they are marked with a straight voltage rating (240 or 480). See Art 200.6 for identification of the grounded leg. See Art 250.24(C). Also 240.85 if using breakers.

Wait for other for a more lucid explanation!

 

[pismo]

I'm trying to find some more info on corner grounded delta systems, the company I work for wants to install one and I told them that it's not a very safe system can anyone help?

I think you are required to ground one leg. Otherwise you may get transient voltages. It the same as grounding the center of a winding on a delta or the center of a Y transformer. When you read voltage with a meter to the grounded leg it will be zero. But between any of the others it will be whatever the applied voltage is.

 

[thinfool]

Why is it not a safe system? The coal industry uses corner grounded systems profusely. They install a resistor in the grounded phase and monitor the current thru it. When the current exceeds a predetermined level, the sensing device trips a shunt trip on the main breaker, leaving a deenergized system for maintenance to repair.
On a corner grounded system, lighting/receptacles are handled by sds transformers. The delta 3 phase system is only used for powering large manufacturing or processing loads.