Commonplace of MCB-type distribution panels?

[creyc]

Is it commonplace to find in an electric room of a commercial building, an MCB type 400A distribution panel feeding 3-4 225A MLO-type panels out of breakers?

The distribution panel is fed from a transformer within the same room, which is itself protected by an enclosed circuit breaker.

Is this common practice? I assume the MCB distribution panel is because the panel is located on the secondary of a transformer?

This might all be kosher, I'm just trying to learn a bit more about the things I'm asked to draw.

 

[infinity]

Yes that is a quite common arrangement.

 

[charlie b]

I design most of my buildings with that sort of arrangement. But I am not sure what you are describing as being protected by an enclosed breaker. You have an main breaker on the distribution panel, so the enclosed breaker would not be needed on the transformer secondary. Do you mean there is an enclosed breaker in the same room, and that it is on the primary side of the transformer? I would not do that myself. The breaker on the upstream panel is all I use to protect the transformer primary. A second breaker in the same room as the transformer is not needed.

Welcome to the forum.

 

[creyc]

Correct, the enclosed breaker is protecting the primary of the transformer.

The transformer is fed from switchgear located on the other side of the building, so I'm not sure the purpose of the ECB myself, perhaps to have the ability to kill power to the transformer without turning off everything else in the elec room? (high voltage panels, for example)