In the past month, I’ve done a series of articles on elements of an electrical safety program. Today, I’d like to wrap up the series by discussing two important aspects of electrical safety that I haven’t yet covered: meter safety and PPE.

Meter Safety

We ask participants in our training program to bring a test meter with them to determine the safety category rating and compliance with IEC 61010-1 (Independent Electrical Contractor Safety requirements for electrical equipment for measurement, control and laboratory use - Part 1: General requirements). Non-category-rated meters get “impounded” under what we call the “meter amnesty program.” This always invokes an interesting discussion and is an effective approach for demonstrating to trainees how to determine the suitability of meter instruments for particular tasks.

IEC 61010-1 specifies categories of over-voltage based on the distance from the power source and the natural dampening of transient energy that occurs in an electrical distribution system. Higher-safety category meters are required when working closer to the power source because they offer more protection. The digital meter impulse rating for transient high-voltage spikes and “creepage” distance (along surfaces) and “clearance” distance on Category III and IV meters helps reduce the potential for meter failure (which can lead to a two-stage arc flash).

I recommend that digital meters be rated minimum Category III (1000 volt) for the distribution level, and Category IV (600 volt) for the supply level, main services and outdoors. Many new digital meters have a dual rating meeting these criteria.

Personal Protective Equipment

PPE for the hands consists of leather and voltage-rated rubber gloves that are rated in incremental voltages starting at:

• Class 00: up to 500 vAC
• Class 0: up to 1,000 vAC
• Class 1: up to 7,000 vAC
• Class 2: up to 17,000 vAC
• Class 3: Up to 27,000 vAC

Outer leather protective and inner voltage-rated “V” rated rubber gloves are required at all times when working on voltages of 50 and above. We’re from Canada and thus recommend requiring gloves at 30 volts and greater to be in line with the Canadian Electrical Code [CEC].

A great starting point is to purchase leather and voltage-rated rubber gloves for all their workers who perform any live work and/or troubleshooting. Other recommended purchases include fused leads for some test meters (which reduce the possibility of arc flash caused by meter failure/user error) and extended leads to keep workers’ hands that much farther from live surfaces.

Protective Clothing

Protective clothing must be 100% natural fiber, such as cotton, and it must be FR (fire-resistant) rated. Protective clothing is also rated by the arc thermal performance value (ATPV) in cal/cm2. This rating must be marked on the clothing by the manufacturer. Special washing techniques are required for the clothing. For example, no bleach or fabric softener can be used. Clothing must be properly maintained and can’t be used as PPE/C when soiled or dirty. Some clothing is chemically treated; other clothing is manufactured from an FR-rated fabric.

PPE/C is rated as follows:

• Category 0: ATPV is NA, no cal/cm2 rating—just natural fiber
• Category 1: ATPV 5 to 7 cal/cm2
• Category 2: ATPV 8 to 24 cal/cm2
• Category 3: ATPV 25 to 39 cal/cm2
• Category 4: ATPV 40 cal/cm2
• Category 4+: “No Category Found” danger category. Must never work live.

LOTO (lockout tagout) and test-before-touch verification techniques are required. This may be a new concept for many electrical workers. To test for power, workers need to open panels and wear the appropriate PPE/PPC to meet the requirements of their electrical safety program. Past practices, such as bare-hand work on de-energized live surfaces, are not recommended—a back-feed could occur causing a voltage rise before the overcurrent device trips and, without protective PPE, the worker could be injured.

Conclusion

Electricity is a complex force of nature and working with and around it in safety requires a variety of measures from training to protective equipment. The road to an effective electrical safety program may seem long, but by getting started and taking the journey one step at a time, your organization will reach its destination before you know it!

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