Isolating transformer for lighting circuits
- Thread starter Kaaud
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More information would be good. I can make some guesses, but without specific information on the installation - I could easily be dead wrong.
Now for the guesses:
The lighting transformer: The distribution system is impedance grounded 480Y. You can't put lighting on impedance grounded 480. The xfmrs are 480D to grounded 480Y - a small one for each area. Lighting is from a dedicated panel and is either 277V or 480V.
Earthing switch on MV generator:
There are a couple of different things this one could be:
Earthing is a european electrical term - not used much in the US. One use I have seen is some european MV switch boards incorporate an earthing switch in each CB. When the feeder is disconnected from the bus, the feeder can be earthed to drain all residual energy. This is considered suitable for maintenance in lieu of grounding using a spyder (grounding clamps and cables).
Now if the gen is connected to the load side of this type of a CB, then you have the capability of grounding the output of the generator - bad idea, but happens when the design uses feeder type CBs for incoming power.
carl
Now for the guesses:
The lighting transformer: The distribution system is impedance grounded 480Y. You can't put lighting on impedance grounded 480. The xfmrs are 480D to grounded 480Y - a small one for each area. Lighting is from a dedicated panel and is either 277V or 480V.
Earthing switch on MV generator:
There are a couple of different things this one could be:
Earthing is a european electrical term - not used much in the US. One use I have seen is some european MV switch boards incorporate an earthing switch in each CB. When the feeder is disconnected from the bus, the feeder can be earthed to drain all residual energy. This is considered suitable for maintenance in lieu of grounding using a spyder (grounding clamps and cables).
Now if the gen is connected to the load side of this type of a CB, then you have the capability of grounding the output of the generator - bad idea, but happens when the design uses feeder type CBs for incoming power.
carl
Kaaud
Member
we are using 230-400 according to IEC , I will provide u for further details about the transformer after a couple of days ,but I think it is delta-star unearthed .
My boss at the work told me to provide a 3 poles C.B. for every area lighting circuit ,that means that if there is a short circuit in 1 phase ,all the lighting will collapse ,Is protecting the whole area with one 3 pole C.B. a good idea?
My boss at the work told me to provide a 3 poles C.B. for every area lighting circuit ,that means that if there is a short circuit in 1 phase ,all the lighting will collapse ,Is protecting the whole area with one 3 pole C.B. a good idea?
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