Every quality safety and health program provides measures to control electrical hazards. The information provided in this training should be helpful in getting a better understanding of electrical safety. The responsibility for an electrical safety program should be delegated to someone with a complete knowledge of electricity, electrical work practices, and the appropriate OSHA standards for installation and performance.

Everyone has the right to work in a safe environment. Safety and health add value to your business and your workplace. Through cooperative efforts, employers and employees can learn to identify and eliminate or control electrical hazards.

Electrical Hazard Recognition

Electricity has long been recognized as a serious workplace hazard, exposing employees to electric shock, electrocution, burns, fires, and explosions. According to the Bureau of Labor Statistics, in 2016, 134 workers died from electrocutions, which represents a decrease from 174 in 2011. What makes these statistics tragic is that most of these fatalities could have been easily avoided.

The first step toward protecting yourself is recognizing the many hazards you face on the job. To do this, you must know which situations can place you in danger. Knowing where to look helps you to recognize hazards.

  • Inadequate wiring is dangerous.
  • Exposed electrical parts are dangerous.
  • Overhead powerlines are dangerous.
  • Wires with bad insulation can shock you
  • Electrical systems and tools that are not grounded or double-insulated are dangerous.
  • Overloaded circuits are dangerous.
  • Damaged power tools and equipment are electrical hazards.
  • Using the wrong PPE is dangerous.
  • Using the wrong tool is dangerous.
  • Some on-site chemicals are harmful.
  • Defective ladders and scaffolding are dangerous.
  • Ladders that conduct electricity are dangerous.
  • Electrical hazards can be made worse if the worker, location, or equipment is wet.

Electrical Terms

What are Volts? A Volt is a measure of the electrical force that seems to push current along. Think of voltage as a lot of water stored in a high water tank. Because the water tank is high, the water will have more force behind it as it flows down the water pipe to your home. This is why they put water tanks up high! If the same tank was placed at ground level, your water pressure would not be as great. By the way, the symbols commonly used for voltage are “E” or “V”.

What is an “ampere?” An ampere is the unit used to measure the amount of electrical current. Amperage is often referred to as “current” by electrical workers and engineers. Let’s go back to our water tank. If the diameter of your pipe coming from the water tank is large, a lot of water (amperage) will flow through the pipe. If the pipe’s diameter is small, a smaller amount of water will flow through the pipe. If you need a lot of current (many amps) to operate your equipment, you’ll need large wires to run the current or they’ll burn up! The symbol for amperage is “I”.

What is an “ohm?” Think of an ohm as “resistance“. An ohm is the unit used to measure the opposition (a.k.a. resistance) to the flow of electrical current. This is pretty easy to understand. A small water pipe is going to oppose a lot of water from flowing. Relatively little water will be able to flow through the pipe. So, the pipe offers a high resistance to the flow of water. You can see that a large pipe would offer little resistance to the flow of water. Big pipe: a lot of water! It’s that simple. In an electrical circuit, components are usually sources of resistance. Any component that heats up due to electrical current is a source of resistance. The symbol for resistance is “R”.

    • What is a “series” circuit? The current in a series circuit takes only one path. For example, water from high in the mountains may flow down one stream (series) into a river that flows to the ocean.
    • What is a “parallel” circuit? The current in a parallel circuit takes many paths. For example, the water flowing from a water tank up on a hill will flow through many different water pipes (parallel) before it reaches the ocean.

Effects of Electrical Current on the Body

Current Reaction
1 milliamp >Just a faint tingle.
5 milliamps >Slight shock felt. Disturbing, but not painful. Most people can “let go.” However, strong involuntary movements can cause injuries.
6-25 milliamps (women)†
9-30 milliamps (men)
>Painful shock. Muscular control is lost. This is the range where “freezing currents” start. It may not be possible to “let go.”
50-150 milliamps >Extremely painful shock, respiratory arrest (breathing stops), severe muscle contractions. Flexor muscles may cause holding on; extensor muscles may cause intense pushing away. Heart fibrillation possible. Death is possible.
1,000-4,300 milliamps (1-4.3 amps) >Rhythmic pumping action of the heart ceases. Muscular contraction and nerve damage occur; death likely.
10,000 milliamps (10 amps) >Cardiac arrest and severe burns occur. Death is probable.
15,000 milliamps (15 amps) >Lowest overcurrent at which a typical fuse or circuit breaker opens a circuit!
*Effects are for voltages less than about 600 volts. Higher voltages also cause severe burns.
†Differences in muscle and fat content affect the severity of shock.

Overloading an Electrical System Hazard

Overloads in an electrical system are hazardous because they can produce heat or arcing. Wires and other components in an electrical system or circuit have a maximum amount of current they can carry safely. If too many devices are plugged into a circuit, the electrical current will heat the wires to a very high temperature. If a tool uses too much current, the wires will heat up.

The temperature of the wires can be high enough to cause a fire. If their insulation melts, arcing may occur. Arcing can cause a fire in the area where the overload exists, even inside a wall.

To prevent too much current in a circuit, a circuit breaker or fuse is placed in the circuit. If there is too much current in the circuit, the breaker “trips” and opens like a switch. If an overloaded circuit is equipped with a fuse, an internal part of the fuse melts, opening the circuit. Both breakers and fuses do the same thing: open the circuit to shut off the electrical current.

If the breakers or fuses are too big for the wires they are supposed to protect, an overload in the circuit will not be detected and the current will not be shut off. Overloading leads to overheating of circuit components (including wires) and may cause a fire.

You must recognize that a circuit with improper overcurrent protection devices – or one with no overcurrent protection devices at all – is a hazard.

Hopefully you have learned about electricity here, it presents a hazard, which can be unseen and is often overlooked.

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