phase protection

[aarifisher]

i was called to a large supermarket about some power issues, it turnd out thay lost one leg and a lot of equipment was toasted i suspect they also lost the nuetral at some point since some of the equipment where single phase.

now they want phase protection, the service is a 2000 amps 480 volt 3 phase,
can anybody suggest anything.

thank you

 

[kwired]

single phase equipment lost was probably connected to the lost phase.

after losing the phase there was "feed thru" voltage from other phases through three phase or single phase line to line loads. Amount of voltage available will depend on loads connected at time of incident.

phase monitors on individual equipment the best way to go? If you want to protect feeders may involve less monitors but will need controls to drop out the feeders, cutting entire service may not necessarily be desired either.

 

[whillis]

If the store has a main breaker, an Eaton Digitrip unit can be refit to most large breakers and it has a phase loss setting.

 

[charlietuna]

Contact the switchgear manufacturer thru your supplier and ask them to provide you information on "lost phase protection" for the gear you have.