Accidental Death is REAL!!
Electrical Shock Fatalities in the USA
- Electric shocks are responsible for about 1,000 deaths in the United States each year, or about 1% of all accidental deaths.
- Electric shocks cause death in 3-15% of cases. Many survivors require amputation or are disfigured by their burns.
- Electrical injuries can be caused by a wide range of voltages but the risk of injury is generally greater with higher voltages, and is dependent upon individual circumstances.
- Electric shock
- Electrical burns
- Loss of muscle control
- Thermal burns
- A voltage as low as 50 volts applied between two parts of the human body causes a current to flow that can block the electrical signals between the brain and the muscles.
- Stopping the heart beating properly
- Preventing the person from breathing
- Causing muscle spasms
- If an electrical current passes through the human body it heats the tissue along the length of the current flow. This results in deep burns that are permanently disabling.
- Burns are more common with higher voltages but may occur from low voltage.
Loss of Muscle Control
- An electric shock causes painful muscle spasms that can be strong enough to break bones or dislocate joints.
- This often means the person cannot ‘let go’ or escape the electric shock.
- The person may fall if they are working at height or be thrown into nearby machinery.
Burn Injury Survival
- Overloaded, faulty, incorrectly maintained, or short circuits get very hot.
- Even low voltage batteries (12V) can get hot and may explode if they are shorted out.
Arc Flash has 3 issues
- The arc temperature
- The incident energy
- The pressure developed by the expanding gas
The main concern is the arc temperature and ignition of clothing.
Arc Flash Test
An arc flash test used a circuit adjusted to deliver 20,000 amperes at 480 V, 3 phase. The bright light is the arc.
Arc Flash Test 2
As the arc develops (second from top), it melts and vaporizes the metal of the electrodes and the box.
Arc Flash Test 3
This vaporizing metal expands outward with the pressure wave, and the test stand is enveloped in the arc flash explosion.
Arc Flash Test 4
The duration of the arc was about 0.045 sec. The test was set up at the Square D High Power Lab in Cedar Rapids, IA.
Arc Flash Result
Approach to Energized Part
Safety Requirements by Category 0 to 4
Arc Flash Protection
Dressed for Safety
Arc Flash labeling in USA
- Shock hazard
- Burn hazard from electrical current
- Burn from thermal (hot wires)
- Explosions due to Arc Fault
Some Safety Tips
- Never work alone on electrical circuits.
- Use lock outs to prevent accidental circuit activation.
- Wear protective gloves, eye and face protection and clothing.
- Double check the expected voltage before work.
- Always deenergize circuits if at all possible.
- DO NOT ASS-U-ME the circuit is off.
- Always make sure the area around your feet is clear.
- If a ladder is necessary it should be fiberglass.