Outdoor Transformer used Indoors 1

[koolbean]

Is it permissible to use an outdoor liquid-filled transformer, inside a building?

Assuming that it meets local fire regulations....would the transformer be subject to temperature issues...

thanks,

 

[dpc]

Assuming it is legal, the oil-filled transformer will work fine indoors.

Before PCB oil was prohibited, Askarel (Interteen) filled transformers indoors was considered state-of-the-art for indoor transformers. I believe the original EPA building in Washington DC had indoor oil transformers with Askarel.

 

[BJC]

How big is it? It might be cheaper to buy a dry-type transformer than the building modifications required to bring the oil filled unit indoors.

 

[advidana]

There is a lot of restriction for mounting oil types indoor, it was common in the past but not now. What happens if the transformer leaks oil. Oil need to be contained etc- Check the nfpa fire protection hand book and the people that make the oil type transformer they know.

 

[peebee]

See NEC 450.23 - 450.26 for requirements for liquid filled transformers installed indoors.

If a vault is required, see NEC 450.41 - 450.48. Note that drywall is not an acceptable method of achieving the vault fire rating. Vaults are required to be constructed of concrete with a 3-hour fire resistance.

Also -- Factory Mutual generally has much stricter requirements than NEC for transformer installations. Are you required to comply with FM?

Temperature can definitely be an issue. An exhaust fan should definitely be considered bare minimum requirement. As a ballpark number, the heat load in kW will be about 2% of the transformer nameplate capacity.