We have a machine shop with quite a bit of CNC's and other type milling machines . We have some maintenance techs that work on these machines on a regular basis . Was asked about them having to have a " Electrical Hot Work Permit " made out each time they work on a machine . They are on these machines almost every day . Was wondering how other places deal with a " Routine Permit " for this type of troubleshooting and repair work ? How long time period would a permit cover ?