bjohnson64
Member
I recently found out that I have a 112 1/2 KVA, 480 to 240 Volt, three phase Delta-Delta transformer suppling the panel board in my metal working / weld shop. During preventive maintenance, I found that there was a grounded leg and I corrected it. Which leads me to my questions that I hope someone can help me with. Does the NEC require that the secondary of the Delta-Delta transformer be grounded? Or, if not, does the NEC require that a ground detection system be installed to alert personnel that an undesired ground in the system exists? Any help would be appreciated. Bill