Mounting a dry -type transformer in a ceiling

[jar546]

Can you mount an enclosed 45kva 3ph 480/277v to 208/120v wye-type transformer above a suspended ceiling and locate the primary side disconnect for the xfmr in the ceiling too?

 

[Mr. Inspector]

2014 NEC 450.13 (B) Drt-type transformers 1000 v., nominal or less and not exceeding 50 kVA shall be permitted in hollow spaces of buildings not permanently closed in by structure, provided they meet the ventilation requirements of 450.9 and separation from the combustible materials requirements of 450.21(A). Transformers are not required to be readily accessible.

NEC 450.14 requires the disco to be in sight or have a lockable remote disco.

 

[e hilton]

the disco to be in sight .

In sight of what? The transformer, on the person standing on the floor in the room under the elevated transformer. So if you walk into the electric closet, and you know the transformer is above the ceiling, do you need ready access to the disconnect?

 

[jar546]

In sight of what? The transformer, on the person standing on the floor in the room under the elevated transformer. So if you walk into the electric closet, and you know the transformer is above the ceiling, do you need ready access to the disconnect?

Good questions. Within sight of the transformer. The transformer disconnect is not required to be readily accessible.

 

[LCBob]

As previously stated the disconnecting means is required to be "in sight of the transformer or in a remote location."
The 'remote location' portion has some additional requirements such as labeling and lockable.

We need to keep in mind that the required overcurrent protection of the secondary conductors does need to be 'readily accessible'.
NEC 240.24(A)