hello. looking for advice on working on a 3 ph, 3 wire 480 delta that i believe fits the definition of a corner grounded delta. the title of the thread is appropriate because theres only 3 wires marked for each phase and no neutral going into the customers main disconnect switch which powers a 3 phase 480v motor control circuit.
i say its corner grounded because there appears to be a bonding strap tying the middle phase conductor to the meter enclosure but am puzzled at why its bonded at that location especially when the manufacturer's label states specifically, "When service is not grounded, remove [this] bonding strap..."
i think the meter enclosure was intending for the middle conductor to be a neutral (a grounded system) but in this case its not (3 wire, 3 phase delta) or at least not supposed to given the customers requirements for a 3 ph 480v motor.
so my question is where is the proper place to ground a phase conductor? at the pole or pad mounted transformer? at the customer's first disconnect? or at the meter or anywhere else?
i will post pictures as soon as i can figure out how to do so.
i say its corner grounded because there appears to be a bonding strap tying the middle phase conductor to the meter enclosure but am puzzled at why its bonded at that location especially when the manufacturer's label states specifically, "When service is not grounded, remove [this] bonding strap..."
i think the meter enclosure was intending for the middle conductor to be a neutral (a grounded system) but in this case its not (3 wire, 3 phase delta) or at least not supposed to given the customers requirements for a 3 ph 480v motor.
so my question is where is the proper place to ground a phase conductor? at the pole or pad mounted transformer? at the customer's first disconnect? or at the meter or anywhere else?
i will post pictures as soon as i can figure out how to do so.