Earthing Truck

Some of the answers are misleading. MV or medium voltage switchgear, which is for 1100 volts AC to 15000 volts usually has normally got all the conducting surfaces taped or insulated so there is no way to put safety grounds on. The use a a good grounding truck or what some people might call earthing truck across the pond is used to ground usually the load side of the breaker. The best ones allow the unit to be racked in and the lack of power tested before a ground switch in the device is operated or manually engaged. The use of these devices require a good knowledge of the system to be sure that no backfeeds exist or someone does not rack them into a live bus. Deaths have occurred from error.

LV or low voltage switchgear can have voltages up to 1100 volts but are usually below 1000. This type of switchgear does not require taping of outgoing cables as a normal rule and it is a simple to thing to simply remove the back cover after de-energizing and locking out the feeder and installing grounding cables on the outgoing feeder before work is performed.

It's a bit difficult to answer without talking to the <...we...> first.