Outdoor Transformer Installations

[p-elec]

Rule 26-242 (2) states that dielectric liquid-*****d pad-mount distribution transformers shall be installed, "...at least 6m from any window, door, or ventilation inlet or outlet on a building."

Does this distance include windows, doors etc. on the second floor of a building?

If so, the notwithstanding clause 26-242 (4) allows for transformers to be installed within this distance provided that "...a wall or barrier with noncombustible surfaces or material [is] constructed between the transformer and that door, window...".

Would this barrier have to be as high as the line-of-sight between the transformer and the second floor window or door? This would mean a pretty high barrier wall.

Just wanted some clarification. Thanks.

[Tony Moscioni]

This Rule applies only to dielectric liquid-*****d electrical equipment containing more than 46L in any one tank or a total of 137L in a group of tanks.

The intent is to keep burning material away from areas of a building that are susceptible to spread fire in the event the transformer faults and ruptures.

The 6m requirement IS measured "line-of-sight"

Choices are to locate the equipment a suitable distance from combustible surfaces or openings, or installing fire-resisting barriers between the equipment and combustible surfaces or openings.

An example of such a barrier would be a concrete or masonry wall built around three sides of a transformer mounted at the side of a building.


The minimum distance of 6m to doors, windows and ventilation openings cannot be reduced without the use of a suitable fire resistant barrier, unless the transformer is single phase, 167 kVA or less, and has an integral current-limiting device.

Tony Moscioni
Electrical Inspector
Electrical Safety Authority

[p-elec]

Thanks for the help Tony.

I'm assuming this line of sight would include, say a window within this length on the second floor. If so, would I have to build a wall to protect this line of sight? Meaning the wall could possibly be a storey or more high.

[twh]

You could put a roof over it.