FeelingLucky
New member
Hi everyone,
I have a new 3000kVA 16.5kV to 480V Delta/Wye transformer feeding a 4000A Switchboard. The switchboard is a 3 wire system because there is no need for the neutral.
-A 3phase 3wire cable bus system will be connecting the secondary of the transformer to the switchboard main.
-I am using a System Bonding Jumper, included in cable bus system, to connect the neutral of the transformer to the grounding bus bar at the switchboard.
-Grounding Electrode Conductor is connected from the transformer neutral to structural steel.
My Question is:
1. Do I need to supply another ground connection from the Grounding bus bar(at the Switchboard) to structural steel? If so, which table should I use for sizing?
2. Does the second ground connection at the switchboard create a parallel path for neutral current?
3. Which table should be used to size the System Bonding Jumper?
Thank you very much for your input. There has been much argument about this subject between my peers
I have a new 3000kVA 16.5kV to 480V Delta/Wye transformer feeding a 4000A Switchboard. The switchboard is a 3 wire system because there is no need for the neutral.
-A 3phase 3wire cable bus system will be connecting the secondary of the transformer to the switchboard main.
-I am using a System Bonding Jumper, included in cable bus system, to connect the neutral of the transformer to the grounding bus bar at the switchboard.
-Grounding Electrode Conductor is connected from the transformer neutral to structural steel.
My Question is:
1. Do I need to supply another ground connection from the Grounding bus bar(at the Switchboard) to structural steel? If so, which table should I use for sizing?
2. Does the second ground connection at the switchboard create a parallel path for neutral current?
3. Which table should be used to size the System Bonding Jumper?
Thank you very much for your input. There has been much argument about this subject between my peers
