My understanding is if a item of plant (normaly an excavator) damages a HV cable the machine provides little protection from electrocution if the circuit breakers do not kick in immediately. However there would be an element of protection from the molten copper/aluminium produced by the resulting explosion.

Basically if your not killed immediately you might as well get out of the cab and evacuate?

Am I correct and can anyone point me in the direction of further reading/info.

Thanks in advance.

Rob

If you are in an excavator and you hit a cable then the best thing to do is stay there, electricity goes the easiest way to earth through the machines arm and out the tracks, or in a Jake the legs. Do not climb out of the machine, you may be able to jump clear. If the arm is not welded to the cable then move it away, do not let persons near the cable and inform the owner.
HSG47 Avoiding Danger from Underground Services, should be the benchmark for not hitting services.

RayRapp, has it right here are LV & HV services.
BOTH have auto reclosing breakers.
IF LV then you would probably be safe to leave the machine, however, this depends on the exact situation.
Remember we are all sitting near LV at our computers as LV distribution is continued right to the back of a PC/Monitor.
HV "stops" at the local substation.
IF HV then this is doubtful depending on the situation
Not checked the links though I have seen some good stuff from HSE on this.
Report any underground cable stikes IMMEDIATELY to the local DNO / Nationl Grid, you would probably not know whose cable it is so report it to the 1st number you find they will do the rest!

HOWEVER, regardless of my comments unless your operator is SURE of what he has hit then they should stay put as the metal machine with (probably) metal tracks &/or bucket will "act" as a "Faraday Cage" and protect the operator from electrocution as the current will be conducted through the machine.
However, it could also set fire to the machine depending on the cable hit, &/or the machine condition/configuration or the cable could explode / catch fire so then you have a different scenario!

Plant Trainer,
Good points, however, CAT scans are not that good really!
They are so error prone that on times they are worse then useless!
Obviously this is NOT your fault, it is just a limitation of the science of the systems.
Rubber tracks is a good point, I took the machines to be larger as these tend to be on mini & micro machines, which however are being used more often by large contracts/contractors.
One thing though, if the metal bucket is in the ground this will provide a better electrcial earth path than the machine/operator "in general" & the rubber tracks will prevent the machine becoming live from a cable below these.

I agree with the Catscan comments but would also reiterate that all control measures should be followed, service plans, etc searched and advice sought, at the end of the day using the excavator is a means of speeding up the excavation, whenever doubt exists about the location of any services the only choice is caution, use mechanical means to loosen the surface then carefully hand dig until the services are located.
Time spent doing the job safely (if slowly) is far better than delays while utility companies turn out to make repairs or far worse time and money lost and hardship caused following an accident.