Two points on this-
First of all, if it's a civil helicopter, the stuff on the hoist should have been tested for some pretty stringent EMC / EMI fields.
Secondly, the presence of something like this on a hoist in a civil helicopter is one of the reasons why you'll see phrases in the Flight Manual Supplements for hoists like 'Not approved for human cargo'. Strange isn't it?
But this is the only way engineers in the certifying authority can put their hands on their hearts and say that they've done their job. How you as an operator are supposed to use the equipment is not their problem
Hint- you can invoke the 'emergency' clause in most operating rules to override anything in the flight manual to save human lives.
And I'm sure that will help when the lawyers come around after the cable cutter blows when operating near a power line.