Electrical Shock

Electricity plays an important role in our daily lives and at work. Farmers and gardeners rely on electricity to perform a number of tasks involving lighting, tools and equipment. Care must be taken to avoid potential injury or death from exposure to electrical circuits. There are four main types of electrical injuries, grouped into two subtypes.

• Direct:
  • Electrical shock
  • Burns
  • Electrocution (death) due to an electrical shock
• Indirect:
  • Falls from elevated locations as a result of being shocked.

Basic Terminology

• Shock: When electrical current passes through the body by contacting part of the electrical circuit.
• Electrocution: Death resulting from electrical shock.
• Voltage (volts): Electrical force and potential, measured in volts.
• Current (amps): Volume or intensity of electrical flow (flow of electrons).
• Power (watts): Power consumed (measure of work).
• Resistance (ohms): Restricted flow of a current (higher resistance = lower current).
• Hot conductor: A conductor that carries the electrical current.
• Grounding conductor (neutral): Carries the current in normal operation but is connected to the earth (zero volts/potential).
• Ground: Physical connection to the earth, which is zero volts.

Electrical shock occurs when part of the body completes a circuit between conductors of different voltages or between an electrical source and a ground. Wet skin has little or no resistance to electrical current flow and increases the danger of electrical shock or burns. Avoid damp or wet areas.

Higher voltages increase the risk of death by electrical shock. Avoid contact with exposed electrical conductors and connectors, and also with improperly insulated equipment. Even very small currents can kill. Severity of shock depends on the:

• Path of the current through the body.
• Amount of the current flowing through the body (amps).
• Duration of the shock.

The effect of electrical shock depends on the amount of current flow and the current’s path through the victim’s body. People have survived shocks of several thousand volts, while others have been killed by voltages as low as 12. To prevent electrical shock, prevent body parts from contacting the circuit or becoming part of the electrical flow and a path for the current.

Safety Tips for Working Around Electricity

General

• Inspect the area for electrical hazards.
  • Check for exposed electrical wires.
  • Check for damaged electrical boxes.
  • Call the local electrical utility service to locate underground wires.
  • Avoid contact with overhead wires when working with long objects up in the air such as ladders, pruning shears and pruning saws, or when operating tall equipment.
  • Shut off the power in the case of an electrical fire.
  • Use a fire extinguisher approved for electrical fires to fight the fire.
  • Do not use water to put out an electrical fire. Water can result in a fatal shock.

Equipment and Cords

• Inspect wires and plugs before each use.
  • Repair or replace damaged wires or plugs before using them. Do not place tape over gashes in a wire. Instead, replace the wire.
  • Do not splice wires.
• Use approved extension cords only temporarily (for less than 90 days).
  • Install permanent wiring where use exceeds temporary needs.
• Make sure extension cords are appropriate for outdoor use, and make sure the electrical load does not exceed the rated capacity.
  • Avoid using multi plug adaptors or plugging multiple extension cords together.
  • Be aware that circuit overloading can occur and can increase the risk of fire.
• Use only double-insulated power tools or equipment with three-prong plugs.
  • Do not use equipment with broken prongs.
  • Stop using a tool immediately if a tingling sensation is felt while using it. Then, take the tool out of service.
• Avoid using electrical equipment in damp or wet areas.
  • Protect plugs and outlets from moisture in the environment.
  • Do not leave a plug connection in a puddle or other collection of water.
  • Use a GFCI when these areas can’t be avoided. See Grounding and GFCI Protection, AEX-790.21.
• Use lockout/tagout devices when working on equipment. See Lockout/Tagout, AEX-790.22.

Helping an Electrical Shock Victim

• Call for help immediately.
• Stop the flow of electricity in the victim’s body by disconnecting or de-energizing the circuit, if the victim is unable to pull away from the current source. 
• Do not try to remove the victim from the current source. Touching the victim could cause the rescuer to be shocked as well.

References

NFPA 70E—Standard for Electrical Safety in the Workplace. Quincy, MA: National Fire Protection Association, 2009. 

Reviewer: Kent McGuire, CFAES Safety and Health Coordinator, Food, Agricultural and Biological Engineering