mdw228
Member
- Location
- Baton Rouge, LA
There was an incident at the refinery that i work at a couple of years ago that involved an individual wiring one phase to ground of a welding machine during a shutdown. Because of our high resistance grounding that is on the secondary side of all of our 480 V transformers, this ground fault was not detected. Consequently, every time the welding machine was used, people were getting a nice buzz when they touched a nearby stairwell (no one was hurt, thank goodness).
A recommendation has come about to look into providing ground fault protection for 480 V equipment that is brought into the plant to use on a temporary basis during shutdowns. All of our step-down transformers to 480 are D-Y with a high resistance ground. Is it possible to give ground fault protection on a four wire system with a high resistance ground? Everything that I've found online is a three wire system, which I'm guessing monitors for an imbalance between phases.
Let me know if any other details are needed. I'm a young dumb engineer. So, I may be leaving some pertinent information out.
A recommendation has come about to look into providing ground fault protection for 480 V equipment that is brought into the plant to use on a temporary basis during shutdowns. All of our step-down transformers to 480 are D-Y with a high resistance ground. Is it possible to give ground fault protection on a four wire system with a high resistance ground? Everything that I've found online is a three wire system, which I'm guessing monitors for an imbalance between phases.
Let me know if any other details are needed. I'm a young dumb engineer. So, I may be leaving some pertinent information out.