CASE STUDY 3 - ELECTRICAL SAFETY

The defective insulation hazards

Introduction

An electrical hazard is a dangerous condition where a worker can or does make electrical contact with energized equipment or a conductor.  From that contact, the person may sustain an injury from shock, and there is a potential for the worker to receive an arc flash (electrical explosion) burn, thermal burn or blast injury.

Improper grounding hazards

A damaged live power tool that is not grounded or double-insulated is very dangerous! When an electrical system is not grounded properly, a hazard exists. The most common OSHA electrical violation is improper grounding of equipment and circuitry.

• Grounding is the process used to eliminate unwanted voltage.
• A ground is a physical electrical connection to the earth.
• Electrical equipment must be properly grounded.
• Grounding reduces the risk of being shocked or electrocuted. 
• The ground pin safely returns leakage current to ground.
• Never remove the ground pin.

Overload hazards

Instead of us running another circuit or extension cord to a different circuit to split the electrical load, we just keep adding devices until the circuit breaker trips.​ Electrical circuit overloads happen when more amperage is put across an electrical wire or circuit than it can handle.

• Overloaded circuits can cause fires. 
• Use proper circuit breakers.
• Never overload an outlet.
• Do not use power strips or surge protectors on construction sites.
• Use a 3-way extension with a GFCI instead.

Wet condition hazards

Damaged insulation, equipment, or tools can expose you to live electrical parts. A damaged tool may not be grounded properly, so the housing of the tool may be energized, causing you to receive a shock. Improperly grounded metal switch plates and ceiling lights are especially hazardous in wet conditions. If you touch a live electrical component with an uninsulated hand tool, you are more likely to receive a shock when standing in water.

• Wet conditions are hazardous.
• Damaged insulation increases the hazard.
• Always avoid using tools in wet locations
• Water increases the risk of electric shock.

Preventive measures in electrical safety

General Prevention Measures. Do not expose the live part of any electrical appliance or wire. Reduce the severity of electric shock accidents by installing circuit breakers. Limit the authorized personnel responsible for handling switches on electrical appliances

Protection from direct contact

Direct contact electric shock is the result of simultaneous contact by persons or livestock with a normally live part and earth potential. As a result the victim will experience nearly full mains voltage across those parts of the body which are between the points of contact.

• The insulation of live parts - this is the standard method. The insulated conductors should be further protected by sheathing, conduit, etc.
• The provision of barriers, obstacles or enclosures to prevent touching (IP2X). Where surfaces are horizontal and accessible, IP4X protection (solid objects wider than 1 mm are excluded
• Placing out of reach or the provision of obstacles to prevent people from reaching live parts
• The provision of residual current devices (RCDs) provides supplementary protection but only when contact is from a live part to an earthed part.

Protection from indirect contact

Occurs due to contact with a part which is connected to the electical installation, possibly due to damages in the appliance or insulation, resulting in leakages of current.

• Making sure that when a fault occurs and makes the parts live, it results in the supply being cut off within a safe time.

• Cutting off the supply before a fatal shock can be received using a residual current device

•  Applying local supplementary equipotential bonding which will ensure that the resistance between parts which can be touched simultaneously is so low that it is impossible for a dangerous potential difference to exist between them. It is important to stress that whilst this course of action will eliminate the danger of indirect contact, it will still be necessary to provide disconnection of the supply to guard against other faults, such as overheating.

To create a safe working environment

• To eliminate any accidents which can result in physical damage or loss of life or propety.
• Failure to meet the safety regulations may result in electrical shocks. 
• Encourage workers disciplined and always give importance to safety.

Lock out and tag out circuits and equipment

• All electrical source. 
• Place on each disconnecting means used to de-energize circuits.
• Attach lock to prevent operating.
• place tag with each lock

Overload wiring by using the right size and type of wire

Use the Right Size and Type of Wire to Prevent Overload – An electrical hazard exists when the wire is too small a gauge for the current it will carry. When a wire is too small for the current it is supposed to carry, the wire could overheat and cause a fire.

For Example:

The size of the wire placed into the circuit may be too small for the load or a tool plugged into an extension cord may use more current than the cord can handle.

What will happen if we not control electrical safety?

• It will cause of death during do the maintaince
• The wire may peel of during cutting and cause the electric shock
• Shock circuit will happen

Conclusion

The control of electrical hazards is an important part of every safety and health program. The measures suggested in this booklet should be of help in establishing such a program of control. The responsibility for this program should be delegated to individuals who have 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. Through cooperative efforts, employers and employees can learn to identify and eliminate or control electrical hazards.

Reference

• http://www.elcosh.org/document/1624/891/d000543/section5.html
• https://www.osha.gov/dte/grant_materials/fy08/sh-17792-08/electrical_english_r6.pdf