Deal with this a lot. Call the power company theyíll disconnect you at the mast. Youíll have no power or weight on the mast.
Donít know if your talking about shingle siding or roof but either way get as much work done up close to the area as you are comfortable with so when they unplug you can get past that point quick.
Anywhere Iíve worked the service is FREE, they donít want you to get fried either.
Have a crew on standby to deal with the perishables if need be.
EDIT: I guess you did post this in roofing,
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