pdesai1071
New User
- Location
- Chicago, IL
- Occupation
- Electrical Engineer
Scenario:
Two Building Transformers 208V Delta - 208/120V Wye ( Isolation Transformers) are connected in M-T-M switchboard configurations within the same electrical room.
Questions:
1. Is it acceptable to establish GEC and Supply Source Bonding (N & G) at the M-T-M Switchboard, or this has to be established at the secondary of the transformers?
2. If the GEC and System Supply Grounding are established at the transformers, please confirm if the switchboard ground bar is not required to connect to the external service ground electrode, but the ground conductor is to be installed with the phase conductor from the transformer to the switchboard.
3. Does the M-T-M require 4 Pole C.B. (Switched Neutral)?
4. Is it okay to use 3 pole C.B. with the use of a common natural bus?
5. Because both the service transformers will have the GEC at the same ground potential, is it necessary to provide the differential ground relay within the switchboard?
Two Building Transformers 208V Delta - 208/120V Wye ( Isolation Transformers) are connected in M-T-M switchboard configurations within the same electrical room.
Questions:
1. Is it acceptable to establish GEC and Supply Source Bonding (N & G) at the M-T-M Switchboard, or this has to be established at the secondary of the transformers?
2. If the GEC and System Supply Grounding are established at the transformers, please confirm if the switchboard ground bar is not required to connect to the external service ground electrode, but the ground conductor is to be installed with the phase conductor from the transformer to the switchboard.
3. Does the M-T-M require 4 Pole C.B. (Switched Neutral)?
4. Is it okay to use 3 pole C.B. with the use of a common natural bus?
5. Because both the service transformers will have the GEC at the same ground potential, is it necessary to provide the differential ground relay within the switchboard?