Was told a similar tale by an EDF engineer.

The 'thieving ********ie scum' remove the security fences around
substations and back a Transit into the enclosure of the transformer.
They then lob a bike chain over the three phases aiming to blow the
supply fuses. Their next step is to cut and remove the earth cable.
Unfortunately - and I don't understand this bit - there can be a high
current present in the earth cable even after the fuses have blown.
He has attended to one of these 'outages' and found boltcutters with
attached fingers next to the cut, but not removed, earth cable.
Naturally no tears are shed.

R