I'm trying to give advice on the civil design of the transformer room. The draft design is a single room that is to house both the RMU and the 3MVA 33kV/400V dry type transformer. My question and a concern in the design is placing both the RMU and the transformer on the same building. I want to know if there is any standard that guides against that.
RMU and Transformer Room
- Thread starter Mthevo
- Start date
Julius Right
Senior Member
- Occupation
- Electrical Engineer Power Station Physical Design Retired
In my opinion, you may install the RMU and the transformer in the same room, but this has to be according to NESC C2 [2017] and NEC 2023.
NESC C2 180. Switchgear assemblies
152. Location and arrangement of power transformers and regulators
NEC Art.110 Part II. Over 1000 Volts, Nominal
NEC 110.56 Energized Parts. Bare terminals of transformers,
switches, motor controllers, and other equipment shall be
enclosed to prevent accidental contact with energized part.
NEC Art.450 Part II. Installation
NESC C2 180. Switchgear assemblies
152. Location and arrangement of power transformers and regulators
NEC Art.110 Part II. Over 1000 Volts, Nominal
NEC 110.56 Energized Parts. Bare terminals of transformers,
switches, motor controllers, and other equipment shall be
enclosed to prevent accidental contact with energized part.
NEC Art.450 Part II. Installation
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
My opinion does not matter much but it seems to me that putting all this stuff in one room is going to make it pretty large. Personally I think big transformers should be outside.
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
Data Centers buy MV transformers and LV switchgear as a single assembly. 3250KVA 16kv-480V. The simple answer is there is no rule against it.
You will have to consider the transformer type and the spacing of equipment. I would also say that depending on the location, it might be better to isolate the two to separate rooms for worker safety. There could also be rack out or hot sticking procedure that should be considered for MV applications.
For example, if you have a water line or fire pump in the same room, you are going to have plumbers or by NEC consideration, non-qualified workers, in an area where exposed live parts could create hazards. So if you fence off or ensure there are no exposed live parts, then you have to ensure that there is still safe working spaces for the qualified electrical workers.
Some people who are comfortable working on LV are not trained on clearances or safe working practices around MV and that is also a consideration for qualified vs non-qualified.
You will have to consider the transformer type and the spacing of equipment. I would also say that depending on the location, it might be better to isolate the two to separate rooms for worker safety. There could also be rack out or hot sticking procedure that should be considered for MV applications.
For example, if you have a water line or fire pump in the same room, you are going to have plumbers or by NEC consideration, non-qualified workers, in an area where exposed live parts could create hazards. So if you fence off or ensure there are no exposed live parts, then you have to ensure that there is still safe working spaces for the qualified electrical workers.
Some people who are comfortable working on LV are not trained on clearances or safe working practices around MV and that is also a consideration for qualified vs non-qualified.
Julius Right
Senior Member
- Occupation
- Electrical Engineer Power Station Physical Design Retired
RMU is for 33 kV: two Feeder cables, one for transformer.
The transformer of dry-type has to be inside located.
RMU width is about 1 m and transformer 2 m.
The transformer of dry-type has to be inside located.
RMU width is about 1 m and transformer 2 m.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Why?
Do you consider "cast coil" transformers to be "dry type".
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
is this installation in an area subject to the NEC? Your voltages infer a non-North American location?