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No. 277 August 2011 Arc Flash Hazards Potential Hazard: Workers who work nearby to unprotected, energized electrical equipment or electrical conductors may be at risk for exposure to an arc flash. Exposure to an arc flash may cause burns, hearing loss, respiratory damage, blindness or even death. An arc flash is a short circuit (and possible release of electrical energy) that flashes through the air from one conductor or piece of electrical equipment to another conductor or piece of electrical equipment or ground. Any work done on energized electrical equipment may result in an arc flash. How to control the hazard: To control arc flash hazards at the workplace, workers and employers need to know these key things: The best way to control an arc flash hazard is not to conduct work on energized electrical equipment or conductors. This means that any work to electrical equipment is done while the equipment is under a de-energized electrical state. An employer must ensure that a licensed electrical worker performs the electrical work. If it is not practical to work on electrical equipment while it is de-energized, the employer must take steps to ensure that the work is done following safe work procedures and proper electrical control. De-energized Electrical State: A de-energized electrical state refers to de-energizing and locking out electrical equipment on which the work is to be done, following the requirements of Manitoba’s workplace safety and health regulation (see specifics on page 2). It also refers to removing any potential stored power/energy source from the equipment to be worked on, and not re-energizing the equipment until the work has been completed and all persons nearby are in a safe location. Electrical Control: The employer must ensure that an arc flash hazard analysis is conducted for all electrical equipment to be worked on in an energized state, unless the following conditions are present: The circuit is rated 240 volts or less; The circuit is supplied by one transformer; and The transformer supplying the circuit is rated less that 125 kVA. The findings of the arc flash hazard analysis must be posted on the piece of equipment. Safe Work Procedures: The employer must consult with the electrical worker to assess the conditions or circumstances under which the electrical worker is required to work, and following this assessment, to develop safe work procedures (SWPs) for the task. Workplace Safety and Health Division Contact Information: Winnipeg: (204) 945-3446 Toll-Free: 1-866-888-8186 (Manitoba only) 24-Hour Emergency Line: (204) 945-0581 Publications/resources available at: www.safemanitoba.com

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Page 1: Arc Flash Hazards - SAFE Work Manitoba Related Documents/uploads... · To control arc flash hazards at the workplace, workers and employers need to know these key ... Ensure the SWPs

No. 277

August 2011

Arc Flash Hazards

Potential Hazard:

Workers who work nearby to unprotected, energized electrical equipment or electrical conductors may be at risk for exposure to an arc flash. Exposure to an arc flash may cause burns, hearing loss, respiratory damage, blindness or even death. An arc flash is a short circuit (and possible release of electrical energy) that flashes through the air from one conductor or piece of electrical equipment to another conductor or piece of electrical equipment or ground. Any work done on energized electrical equipment may result in an arc flash.

How to control the hazard: To control arc flash hazards at the workplace, workers and employers need to know these key things:

• The best way to control an arc flash hazard is not to conduct work on energized

electrical equipment or conductors. This means that any work to electrical equipment is done while the equipment is under a de-energized electrical state.

• An employer must ensure that a licensed electrical worker performs the electrical work. • If it is not practical to work on electrical equipment while it is de-energized, the employer

must take steps to ensure that the work is done following safe work procedures and proper electrical control.

De-energized Electrical State: A de-energized electrical state refers to de-energizing and locking out electrical equipment on which the work is to be done, following the requirements of Manitoba’s workplace safety and health regulation (see specifics on page 2). It also refers to removing any potential stored power/energy source from the equipment to be worked on, and not re-energizing the equipment until the work has been completed and all persons nearby are in a safe location. Electrical Control: The employer must ensure that an arc flash hazard analysis is conducted for all electrical equipment to be worked on in an energized state, unless the following conditions are present:

• The circuit is rated 240 volts or less; • The circuit is supplied by one transformer; and • The transformer supplying the circuit is rated less that 125 kVA.

The findings of the arc flash hazard analysis must be posted on the piece of equipment. Safe Work Procedures: The employer must consult with the electrical worker to assess the conditions or circumstances under which the electrical worker is required to work, and following this assessment, to develop safe work procedures (SWPs) for the task.

Workplace Safety and Health Division Contact Information:

Winnipeg: (204) 945-3446 Toll-Free: 1-866-888-8186 (Manitoba only) 24-Hour Emergency Line: (204) 945-0581

Publications/resources available at: www.safemanitoba.com

Page 2: Arc Flash Hazards - SAFE Work Manitoba Related Documents/uploads... · To control arc flash hazards at the workplace, workers and employers need to know these key ... Ensure the SWPs

Page 2 Arc Flash Hazards Bltn. 277 Safe Work Procedures (cont’d): The employer must:

1. Ensure the licensed electrical worker(s) is trained in the SWPs and able to follow this training in order to help protect their safety and health and the safety and health of others while performing their task(s).

2. Designate a worker who is trained in emergency response procedures to serve as a standby worker at the work location.

3. Ensure the SWPs include the use of personal protective equipment (PPE) appropriate for the work to be done, and that electrical workers wear all PPE as required.

Personal Protective Equipment (PPE):

To select appropriate PPE, the employer can use one of the following methods: • Consult a hazard category classification table (CSA Z462 Table 4) • Perform an arc flash hazard calculation to determine the available incident arc energy

(IEE* 1584). (*IEE – Industrial European Electrical) The findings of this analysis will determine the arc flash protection boundary and the personal protective equipment to be used. The arc flash protection boundary is the area around the energized electrical equipment or conductor where a worker could receive second degree burns if an arc flash occurred. (For more information on the PPE required see the CSA standard noted below.)

Warning Labels:

All electrical equipment that may pose an arc flash or shock risk to a worker must be identified with an approved warning label.

1. This label should be placed on all new electrical equipment as of 2006.

• Note: Arc flash and shock hazard warning labels installed on the equipment does not mean that an arc flash analysis has been completed.

2. Minimum requirements for arc flash label:

• Arc Flash and Shock Hazard

Appropriate PPE required (hazard analysis label) as per CSA Z462, section 4.3.3.3.

Reference to legal requirements under workplace safety and health legislation: o First Aid Kits and Training: Manitoba Regulation 217/2006 Part 5 o Personal Protective Equipment: Manitoba Regulation 217/2006 Part 6.8; 6.11; 6.13; 6.14 o Machine Tools and Robots (Safe Work Procedures, Lockout, Tag out, Work on Energized

Equipment): Manitoba Regulation 217/2006 Part 16 o Electrical Safety (Electrical Workers, Safe Work Procedures, Emergency Procedures, Work On

Energized Equipment, Stand-by Worker: Manitoba Regulation 217/2006 Part 38 o CSA Standard: CSA Z462-08 Workplace electrical safety Additional workplace safety and health information available at www.safemanitoba.com