Workplace Electrical Safety
CSA Z462 addresses workplace electrical safety and is considered best-practice in Canada. It is used by nearly all Canadian companies that deal with energized electrical equipment, with some exceptions. For example, CSA Z462 does not generally apply to watercraft, railways, and some aspects of communications and utilities work. The standard has recently been updated and harmonized with additional Canadian standards, including CSA Z460, Control of hazardous energy - Lockout and other methods; M421-16, Use of electricity in mines; and Parts I, II, and III of the Canadian Electrical Code.
In terms of protective clothing, CSA Z462 references two primary standards:
- ASTM F1506 for regular PPE.
- ASTM F1891 for rainwear.
To be compliant to CSA Z462, garments must meet one of these two standards. All garments compliant to these standards are arc rated, and the arc rating is used to determine the PPE category of the garment.
CSA Z462 offers two basic methods for selecting PPE:
- The incident energy analysis method is straightforward, breaking up required PPE at 12 cal/cm² and requiring that the arc rating of the system meet or exceed the estimated incident energy.
- The arc flash PPE category method is more commonly used and specifies five PPE categories, as shown in the chart below:
Arc Flash PPE Category
In order from lowest to highest level of protection
Minimum Arc Rating
Measured in cal/cm2
CAT 1 ≥ 4 CAT 2 ≥ 8 CAT 3 ≥ 25 CAT 4 ≥ 40 CAT 5 ≥ 75
- The five categories are delineated according to the risk associated with specific tasks, based on factors including potential incident energy and working distance.
- The categories range from 1 to 5, with 1 being the lowest amount of arc flash protection required, and category 5 (added in 2021) being the highest.
- Each category has suggested garment systems, as well as a minimum arc rating for the garment system.
Additional guidance on underlayers and proper wear is offered by this standard:
- Non-AR underlayers may be worn under AR PPE, as long as the PPE system’s arc rating is sufficient to prevent breakopen of the innermost AR layer at the expected incident energy level. This is to prevent ignition of non-AR underlayers.
- Non-AR garments cannot to be used to increase the arc rating of the garment system.
- Meltable fibres (such as polyester, polypropylene, etc.) shall not be used in underlayers, but undergarments and socks can contain incidental amounts of elastic. AR layers can contain some amount of meltable fibres, as long as the fabrics meet the requirements of ASTM F1506 or ASTM F1891.
- PPE must be worn as intended – zippers fully zipped, cuffs buttoned, and shirts tucked in.
- Tight-fitting clothing should be avoided. This is because a tighter fit reduces the protective air gap between PPE and the body, thereby increasing the potential for injury.
- Garments must provide necessary protection and should not interfere with tasks.
The CSA Z462 standard was most recently updated in 2021. This edition included the addition of arc flash PPE category 5. This new category, with a minimum arc rating of 75+ cal/cm², requires the highest level of arc flash protection.
CSA Z462:21 can be purchased and downloaded from the CSA Group website using the link below: https://www.csagroup.org/store/product/CSA%20Z462%3A21/