What requirements and criteria shall be considered in choosing of power switchboard ventilation system?

I have heard about limitation temperature rise for switchboard busbars in continuous operation duty as 80˚C which shall be considered for busbar sizing, is there any reason for it?

When and why are the four pole circuit breakers used as outgoing feeder in switchgears?

What is purpose of anti pumping relay?

What is current chopping phenomenon? In which type of circuit breaker (SF6 or VCB) it is more severe?

I have a three phase - 4 poles ELCB (earth leakage circuit breaker), can I use it for protection of single phase circuit?

Many years ago when I worked in new power plant site for doing of auxiliary system commissioning, we fronted a wonder accident in low voltage switchgear.

Operation group of an industrial network as illustrated figure below decide to replace one of incoming circuit breaker of main distribution switchgear which failed due to a problem in its control mechanism.

How to calculate the suitable busbar according to temperature rise

How can we choose suitable contact resistance for an electrical connection?

what is the maximum load a  11kv load isolator can carry with it interrupter heads?