Earthing Truck & Switch

Hello Guest,

The Earthing Switch is designed to carry the fault current, but is unable to be switched on, to earth the bus system, while the power is on.

It is mechanically possible to insert an Earthing Truck into the older style live Circuit Breaker.

This generally happens when there is similarly marked circuit breakers, xxxx1, xxxx2, xxxx3 and so on, plus some distraction for the user of the Earthing Truck.

I have seen the results of an Earthing Truck being would up by hand into a live 11kV Circuit Breaker - the resultant explosion was immediately horrifically fatal for the two persons involved, plus extensive damage to the busbar system, and other apparatus.

Safety first, check everything, then re-check, ensure the assistant does the same, write down what you are going to do, check it all, tick off the operations as you do each one.

With electricity, you may not get a second chance, if a mistake is made.

Kind Regards....

Let me add some more.

In case of substation isolators have earth switch, when isolator is open earth sw gets closed thereby earthing a particular section of bus while the source breaker is off.

For indoor switchgear, I have seen a very reputed manufacturer, they made the earthing truck accessible while the breaker is rack out and pulled out of the panel board. they have arranges all safety electro mechanical interlock so that no live bus can't be earthed by earthing truck. I have seen this syatem in many of my previous projects.