bill,
I'm with master66 on this one.
Other side of the coin, having a "famous coffee-house" on the end of a HV transformer sounds like a pretty lame excuse for doing work live.
After all, can't it be done at night?.
There is no such thing as no time to "do it dead".
Regardless of the arc flash hazard caused by short-circuit, I'd be concerned with any flash-over distances that these voltages have.
I'd be asking the PoCo about this before the work takes place, after all it is their equipment.
A general "rule" over here in NZ is that all HV gear be de-energised and Earthed (Grounded) before staff are allowed access to the conductors.
