Peter Czutrin
New member
- Location
- Orlando FL
Gentleman,
Question #1:
In a scenario where I have a Utility Service Transformer ~ 30’ from a commercial parking garage, then near it another transformer – Emergency service - that is fed from a generator plant, both 480V 3Ph, 4 wire, on the secondary going into a dual ended main electrical gear. Of course, the main gear has to be grounded to the building structural steel as the main service grounding reference. I will not mention yet the Bonding of the Neutral inside the gear.
Assume a None-Separately derived system (Neutral is Not switched), both neutrals are connected to the Neutral bus in the gear. My question is do I bring in any Grounding wire from any of the Transformers?
Normally, we do not bring in grounding wire from main service transformer, the transformer is grounded at its location, and the gear is grounded to the building, and, if I have an emergency generator than yes I do bring in grounding wire from it because it has to be “equipment grounded”.
However, in the scenario that I described above I have two transformers, so my question is I do not bring in any grounding wire from neither of them or yes from one – the emergency one?
We will have to make sure that the CTs inside the gear will detect faults.
Also, Do I bond the Neutral to ground in the gear?
Question #2:
If I must feed power from the above - call it Building 1 – to a second building’s main electrical rom/gear call it to Building 2, the parking garages will be constructed near each other connected to each other just in different phases.
I view the feed to Building 2 as a sub main feeder. That building 2 gear will be grounded to the building structural steel, and utility and emergency power will come to it from building 1.
The question is do I bring also Grounding wire from building a with the feeder conductors (4 wire) to building 2? The reason I would justify to do it is to place both buildings under very same equipotential grounding levels. Is it necessary?
What with bonding the neutral in the gear in this building 2? It of course directly impacts what is done to Building 1 if bringing grounding wire from there? I would like good analysis of all things considered and best and safest practices.
Thank you,
Question #1:
In a scenario where I have a Utility Service Transformer ~ 30’ from a commercial parking garage, then near it another transformer – Emergency service - that is fed from a generator plant, both 480V 3Ph, 4 wire, on the secondary going into a dual ended main electrical gear. Of course, the main gear has to be grounded to the building structural steel as the main service grounding reference. I will not mention yet the Bonding of the Neutral inside the gear.
Assume a None-Separately derived system (Neutral is Not switched), both neutrals are connected to the Neutral bus in the gear. My question is do I bring in any Grounding wire from any of the Transformers?
Normally, we do not bring in grounding wire from main service transformer, the transformer is grounded at its location, and the gear is grounded to the building, and, if I have an emergency generator than yes I do bring in grounding wire from it because it has to be “equipment grounded”.
However, in the scenario that I described above I have two transformers, so my question is I do not bring in any grounding wire from neither of them or yes from one – the emergency one?
We will have to make sure that the CTs inside the gear will detect faults.
Also, Do I bond the Neutral to ground in the gear?
Question #2:
If I must feed power from the above - call it Building 1 – to a second building’s main electrical rom/gear call it to Building 2, the parking garages will be constructed near each other connected to each other just in different phases.
I view the feed to Building 2 as a sub main feeder. That building 2 gear will be grounded to the building structural steel, and utility and emergency power will come to it from building 1.
The question is do I bring also Grounding wire from building a with the feeder conductors (4 wire) to building 2? The reason I would justify to do it is to place both buildings under very same equipotential grounding levels. Is it necessary?
What with bonding the neutral in the gear in this building 2? It of course directly impacts what is done to Building 1 if bringing grounding wire from there? I would like good analysis of all things considered and best and safest practices.
Thank you,
