Emergency response and incident investigation

Even with the best planning, electrical incidents happen. When they do, the first few minutes decide whether a shock victim survives, and the hours and days afterwards decide whether the organization learns enough to prevent the next one. This lesson covers rescue from electrical contact, first aid for shock and arc flash burns, the legal reporting duties that follow a serious electrical incident, and how to investigate electrical incidents and near misses. HSE-111 covers incident investigation methods in depth.

Planning before the work starts

Emergency response begins with the job briefing, not with the incident. NFPA 70E-2024 added a requirement that job safety planning include an emergency response plan, and CSA Z462 likewise expects the employer to plan for rescue. Before any energized work, the crew should know where the nearest disconnecting means is and how to operate it, who is trained to release a victim and to give first aid and CPR, where the nearest AED and first aid kit are, how to call emergency services from that location (including the site address and access route), and who will meet the ambulance. Ontario construction rules require a competent worker, trained in rescue and CPR and equipped with rescue equipment, to be stationed where they can see the worker doing live work at 300 V or more, other than diagnostic testing (O. Reg. 213/91 s. 191).

Releasing a victim from contact

A person in contact with an energized conductor may be unable to let go, because current above the let-go threshold causes muscles to contract and grip. The rescuer's first duty is not to become a second victim. Touching the victim while current is flowing puts the rescuer in the same circuit.

• Do not touch the victim or anything in contact with them until the circuit is de-energized or you are using rated equipment.
• De-energize if you can do so quickly and safely: open the disconnect, breaker or emergency stop identified in the briefing. This is always the preferred method.
• If you cannot de-energize, and you are trained and equipped, use a rescue hook (an insulated shepherd's hook) or other insulated rescue tool rated for the voltage to pull the victim free, pulling them away from the source rather than towards yourself.
• For low voltage, if no rated tool is available, a dry, non-conductive object such as a dry wooden board or a dry rope may be used by a trained person as a last resort, keeping your own body insulated and away from the conductor.
• For high voltage, do not approach at all. Keep everyone back, call the utility or the facility's high voltage authority to de-energize, and call emergency services.

First aid for electric shock

Once the victim is free of the circuit, the rescuer checks for responsiveness and breathing. If the victim is not breathing normally, call emergency services, start CPR and send someone for an AED. Electrical current can cause ventricular fibrillation, which only defibrillation can reverse; each minute without CPR and defibrillation reduces the chance of survival substantially. An AED is safe to use on a shock victim once they are free of the circuit.

A shock victim who appears to be fine must still be medically evaluated. Electrical injury can cause delayed cardiac arrhythmias, internal tissue damage along the current path that is invisible at the skin, and kidney injury from muscle breakdown. Entry and exit wounds may be small while the internal damage is large. Many employers' procedures require any worker who has received an electric shock, however minor, to be assessed at a hospital or clinic, and to have the event reported and investigated.

First aid for arc flash burns

Arc flash causes thermal burns, sometimes combined with injuries from the blast, flying metal and eye exposure to intense light. First aid priorities are to stop the burning, cool the burn and get medical help:

• If clothing is burning, smother the flames, or have the victim stop, drop and roll.
• Cool burns with cool running water for at least 20 minutes, if it can be done safely. Do not use ice.
• Remove jewellery and loose clothing near the burn, but do not pull away clothing stuck to the skin.
• Cover burns loosely with clean, dry, non-stick dressings or clean plastic film.
• Watch for shock (low blood pressure), keep the victim warm, and treat for possible blast injuries, including hearing loss, eye injury and fractures.
• Call emergency services for any burn larger than the victim's palm, any burn to the face, hands, feet, genitals or major joints, and any arc flash event.

Burns to the face and airway are especially dangerous because swelling can block breathing. Singed nasal hair, soot around the mouth, a hoarse voice or difficulty breathing are signs of airway burns that need immediate emergency care.

Reporting duties

Serious electrical incidents trigger legal reporting duties. In Ontario, section 51 of the Occupational Health and Safety Act requires the employer to notify a Ministry of Labour inspector, the joint health and safety committee or health and safety representative and the trade union immediately when a worker is killed or critically injured, and to send a written report within 48 hours; the scene must not be disturbed except to save life, relieve suffering or prevent further damage, until an inspector permits. Separately, Ontario Regulation 22/04 requires serious electrical incidents, including any electrical contact causing death or critical injury, any fire or explosion caused by electricity that could have caused critical injury, and some near misses, to be reported to the Electrical Safety Authority within 48 hours. Other provinces have similar requirements; in British Columbia, serious incidents are reported to WorkSafeBC immediately, and Technical Safety BC investigates electrical incidents. Workers' compensation claims are reported separately, for example on a Form 7 to the WSIB in Ontario within three days of learning of the injury.

Investigating electrical incidents and near misses

An electrical safety program must include a procedure for investigating electrical incidents. The aim is to find out why the event happened and to fix the underlying causes, not to find someone to blame. Near misses deserve the same attention, because they reveal the same weaknesses without the injury: a tester that showed voltage on a circuit believed to be locked out, a probe that slipped and caused a spark, or a breaker that would not open.

A typical electrical investigation looks at the following questions:

• What was the task, and was it supposed to be done energized? If so, was there a permit and a valid justification?
• Were all sources identified, and was absence of voltage verified at the point of work with a proven tester?
• Were the arc flash labels current, and did the incident energy match the study? Did the protective device operate as expected?
• What PPE was worn, and did it perform as rated? Arc-rated clothing that has been exposed to an arc must be retained as evidence and then removed from service.
• What was the condition of maintenance of the equipment?
• Was the worker qualified for this task, and was supervision adequate?
• What organizational factors played a part, such as production pressure, staffing, scheduling of outages or a culture that tolerated live work?

Investigation findings should be shared widely, without names, through safety meetings, toolbox talks and the electrical safety committee. The corrective actions should be tracked to completion and their effectiveness checked, often through the field work audits described in Lesson 2.