national electrical code

[jerry144]

Can I tie into a 277 volt lighting circuit and transform down to 120 volts and feed ceiling outlets used for promotional purposes?

 

[dpc]

Probably. The transformer needs to be accessible and you must provide transformer protection and 120V circuit protection in accordance with the NEC. This will require additional circuit breakers or fuses on the secondary side of the step-down transformer. You can't really rely on the 277V breaker back in the panelboard to protect anything downstream of the transformer.

 

[peebee]

Slight correction, dpc:

Secondary overcurrent protection is not required on 1-phase 2-wire transformers. See NEC 240.4(F) for details.

 

[dpc]

peebee,

You're right, provided primary protection is sized according to this paragraph.