Electrical shock and arc flash protection: If energized parts operating at 50 volts or more are not placed in an electrically safe work condition (de-energized), other safety -related work practices are to be used to protect workers from
- electric shock incurred directly through contact with any part of the body or indirectly through some other conductive object; and
- burns caused by arc flash.
Protection boundaries: The boundries listed in CSA Z462-08, Workplace electrical safety, are as follows:
- Prohibited approach boundary: an approach distance(limit) from an exposed energized (live) part where any work conductes is considered to be putting workers in direct contact with the energized part.
- Restricted approach boundry: an approach distance (limit) from an exposed energized part where there is an increased risk of shock, due to an electrical arc over and/or inadvertant movement of the part, for personnel working in the close proximity to the energized part.
- Limited approach boundary: an approach distance (limit) from an exposed energized part where a shock hazard exists.
- Arc flash protection boundary: an approach distance (limit) from exposed live parts where a person could receive a second degree burn if an electrical arc flash were to occur. The arc flash protection boundary is not a fixed distance. It is determined by calculation based on.
-
availiable fault current at the electrical equipment;
- time of exposure; and
- the workers distance from the point of the arc flash.
Information taken from Ontario Electrical Safety Code 2009
