What Is Electrical Safety

To avoid such electrocution, FRP or voltage level tested ladder can be used safe electrical work. underground cables ex. Cable trench or buried in dust must be marked with cable route marker.

Objectives

Electricity
Electric shock
Factor influencing electricity
Electric arcs and arc flash
Static electricity
Associated hazard
Controls
Preventive measures

Expand Your Knowledge on [Hazard Type]

What Is Electricity

Electricity is a form of energy resulting from the existence of charge particles (such as electrons or protons ) either statically as an accumulation of charge or dynamically as a current.

Ohm’s Law

V=IR & I=V/R & R=V/I

Define Electrical Shock

Electrical shock is caused by an electric current passing through your body.
A body makes contact with a live conductor when in simultaneous contact with the ground the body completes the circuits and shock is received.
A body makes contact with two wires at different voltages which are interconnected, receives shock if he touches both the wire at the same time.

Effect Of Electric Shock On The Body

50 volts = muscle spasms, breathing difficulties, heartbeat disruptions

The common effects of electric shock are: pain, internal burn, external burn, respiratory failure, cardiac arrest.

Effect Of Electric Shock On Human Body

Electric current (Contact for 1sec)	Effect
Below 1 mA	Not perceptible
1 mA	Threshold of feeling, tingling
5 mA	Slight shock, not painful
6-25 mA (women)	Painful shock, Loss of muscle control
9-30 mA (men)	Freezing current, The person thrown away from the power source
50-150 mA	Extreme pain, Respiratory arrest, Muscles reaction, possible death
1-4.3 A	Fibrillation of the heart, muscular contraction and nerve damage occur, likely death
10 A	Cardiac arrest, severe burn, death is possible

Factors Affecting Severity Of Electric Shock

01. Amount of current
02. Path of current
03. Length time

Other Factor That May Effect The Severity Of The Shock Are

Voltage of current
The presence of moisture in the environment
The health of the person prior of the shock
Depending on these factor the effect can range from a barely perceptible tingle to immediate cardiac arrest.

Causes Of Electrical Fire

Fires of electrical origin can be caused in several ways, such as, Leakage of current due to poor or inadequate electrical insulation Overheating caused due to overloading of electrical outlet
Overheating of flammable materials that are too close to electrical equipment, which is otherwise operating normally.
Ignition of flammable vapor by electrical equipment, which is not operating normally.
Mechanical damage
All theses situation can ignite flammable materials, it the temperature attained by the fault is sufficiently high.

Electric Arcs And Arc Flash

Arcing can occur when the potential of a conductor is high enough to create a conductive path between that same conductor and another one at lower potential.

The resulting arc will be capable of the air gap or insulation, which separates the two conductor.

Very large amounts of energy can be created in short time, possibly less than 1 second.

Electric arcs occur in nature in the form of lighting.

Arcing generates ultraviolet radiation, which can burn the skin and the retina of eye.

Arc flash and its severity
Arc flash boundaries
Best practice to prevent arc flash

01. Arc Flash And Its Severity

When several electrical conductor with significant fault current flowing through then are place close to each other, arc flash occur.

The explosive burst of energy during an arc flash is called an arc blast and it is capable of permanently injuring or killing a human at distances of even up to 20 feet.

The consequences of arc flash are burn injuries, arc eye blindness, hearing loss, secondary injuries and a fire.

The extent of the injuries depend on : Distance of the worker from the hazard Heat

The typical results of an arc flash are: heat more than 35000 F, is produced, flying molten metal object can injuries others present in the line of fire, burns, rapidly spreading fire into the building or an installation, high pressure more than 2000 lbs.per.sq that create a blast, higher level of sound more than 140db which is loud as a gun.

02. Arc Flash Hazard Boundaries

The arc flash hazard boundary id the minimum safe distance from exposed energized conductor or circuit parts that has a potential for an arc flash.

There are three type of hazard boundaries in flash arc:

Prohibited Approach Boundary

It is approach limit at a distance from an live component with in which work considered the same as making contact with live component.

Restricted Approach Boundary

This area, is closer to the live parts and shall only be crossed by a qualified electrical worker using all required PPE. Crossing this boundary for performing work the equipment is still energized requires work permit.

Limited Approach Boundary

It is the minimum distance from an exposed live component where unqualified personnel may safety stand. An unqualified personnel shall not approach closer in this boundary until he is supervised by a qualified and trained worker and using proper PPE.

Zone Area Classification

3. Best Practice To Prevent Arc Flash

Preventive maintenance : it shall help in sustaining reliability, performance and safety.
Risk assessment : the arc flash risk assessment shall indicate the location of arc flash hazards and correct PPE required to be worn during the work.
Labeling and hazard communication plan : electrical must be marked with labels and the labels must be reviewed periodically.
Design and method reviews : A protection scheme design review and operational assessment of the electrical distribution system should be conducted to identify as reduce the potential electrical hazard.
Accurate single-line diagram : an accurate upto date and legible single-line diagram are necessary.
Short circuit and coordination studies : momentary, Interrupting, arcing, current values
General electrical safety training and development : An effective training will workplace aware about the electrical hazard and risk control measures.
Training program for arc flash training and development plan for PPE : Create an arc flash training guarantee that worker fully understand electrical and arc flash hazard and how to mitigate the associated risk.
Documentation and periodic review :The periodic review in the form of audits are necessary to ensure compliance with the regulation to meet the arc flash requirement.

Static Electricity

Static electricity as a source for flammable vapors, gases and dusts is a hazard common to wide variety of industries.

When an electrical charge accumulates on the surface of two materials that have been brought together and then separated a static spark can occur.

One surface becomes charged positively and the other surface becomes negatively charged.

If the materials are not bonded or grounded, they eventually will accumulate a sufficient electrical charge capable of producing a static spark that could ignite flammable vapors, gases and dusts.

Source Of Static Electricity

Liquid flows through a pipe or hose or through an opening in pipe or hose
Spraying or coating
Blending or mixing
Filling tank, drums
Cans or pails
Dry powdered material passes through silo or pneumatic transfer system
Non-conductive conveyor belt and moving appliances are plugged into electrical outlet.

THE Various control measure used for preventing the build-up of electrostatic charged are: earthing, increasing conductivity, anti-static rubber mats.

01. Earthing

Electrical safety :For conducting materials the provision of a conductive path is the best method of preventing the build-up of charge.

Same goes for large tanks containing flammable liquids, where the spaces can be divided by earthed partition, wire or road which prevent the build-up of charges in the content.

Earthing is also used on a smaller scale with mobile containers, such as those on non- conducting rubber tyres, which can acquire static charges. The charge can be dissipated means of an earthing lead.

All earth connections to be grounded with conductive materials for dissipation of charge.

02. Increasing Conductivity

In case of insulators, the conductivity of the material can be increase in order to minimize the build-up of static charge.

03. Anti-Static Rubber Mats

They are designed to reduce or eliminate static electricity by creating a barrier between the ground and the body.

Protective System For Electric Hazard

01. Fuse and circuit breaker

02. Isolation

03. Double insulation

04. Grounding

05. Guarding

01. Fuse And Circuit Breaker

During a short circuit, over current occurs, which melts the fuse and thus, disconnects the power supply from the connected system.

A circuit breaker is a mechanical device in the from of switch, which automatically if the circuit is overloaded. (MCB, ELCB, RCCB).

MCB (Miniature circuit breaker) : It is much more sensitive to overcurrent than fuse also its restoration is easily possible by just switching it ON.

ELCB (Earth leakage circuit breaker) : Earth leakage circuit breaker is used to protect the circuit from the electrical leakage. ELCB cuts off the power at the time of 0.1 second when someone gets an electric shock.

RCCB (Residual current circuit breaker) : Residual current circuit breaker compare the difference in current values between and neutral wires. In case of a fault, the current from the neutral wire is reduced and the RCCB is triggered to trip off the circuit.

02. Isolation

Switching off refers to deploying of electric power. Whereas isolation refers to depriving the equipment of electric power from any source. Include padlock or lock at the source, to prevent the removal of the barrier by unauthorized person. Also it needs to be accessible, easy to operate and clearly labeled.

03. Double insulation

In double insulation the live parts of the equipment are covered by two layers of insulating material. Each layer is capable of adequately insulating the live parts alone, but together they ensure that the occurrence of insulation failure and its associated is extremely improbable.

Regular, maintenance
the insulation must be soundly constructed
the equipment shall be properly used.

04. Grounding

Grounding creates a low-resistance path that connects to the earth and prevent. The buildup of voltages that could cause an electrical incident.

Grounding is only a secondary protective measure to protect against electric shock.

Grounding rods used for grounding should be :

Made of 5/8th inch copper or steel
At least 2 feet from a foundation wall
Located at least 6 feet apart
Driven into the ground to an 8 feet depth

05. Guarding

Guarding is a type of isolation that uses various structures like cabinets, boxes, screens, barriers, covers, and partitions to close-off live electrical parts.

What Is Lock-Out And Tag-Out

Lock-out and tag-out is a safety procedure which forms an integral part of the permit to work (PTW) system. It help of successfully isolate hazardous energy sources and make machines/equipment non-operational, until a task is complete.

Lock-out: lockout a process where a lockout device is used for controlling the release of hazardous energy. During loto, the equipment/machinery is disconnected from power sources, followed by attachment of lockout device on an energy isolating device. It ensures that the energy isolating device and equipment being controlled cannot be operate, until the lockout device is removed.

Tag-put: After locking out the energy isolating device, a tag is placed on it warn people that it may not be started. Tag contain the name of the personnel responsible for the process, along with any other necessary information.

Please note:

01) tag out does not provide the same level of protection as lockout.

02) It is only used on its own when there is no other way to control hazardous energy.

Step Of LOTO Procedure

01. Preparation : We authorized person first identify to machine to be worked on followed by verification of the procedure for shut down and restart. Then the types of hazardous energy need to control.

02. Shut down : After plan it is time to shut down the machine for service and maintain. All the employee affected by the shut down shall be inform.

03. Isolation : To isolate the machine or equipment from any energy source achieved by turning off power backer.

04. Lock out and tag out : After the isolating machine from energy source connect lock and tag out.

05. Stored energy check : After that connecting energy source check any hazardous energy stored in machine and safely performed maintenance.

06. Isolation verification : An authorised person check isolation properly and de-energise free form hazardous energy.

07. Commence the work

08. Clear the work area : After the work completed ensure the non-essential item are removed the equipment.

09. Check the work area : Check the area to ensure all affected employee safely their position.

10. Notify to concern plant supervisor and work is completed.

11. Remove lock and tag from the equipment.

12. Restore energy : re-energise the equipment safely.

Note : the machinery or equipment and operating procedure are regularly updated and changed periodically.

The newly introduced changes, if any are recorded, communicated with employees and then implemented during lockout and tag out.

Stage Electrical safety

Stage1 : identify Hazard

An electrical hazard can be defined as a dangerous condition, where can make electrical contact with energized equipment or a conductor and which can expose the worker to injury from electric shock such as.

Stage2 : evaluate Risk

After identifying the hazard and assessing the risk, appropriate control measures must be put in place.

Stage 3 : Control The Risk

Controlling the risk of hierarchy of risk control

Elimination : This is the most effective measure because it altogether removes the hazard or hazardous work practice.

Substitution : It substitutes high risk method or equipment with an alternative that would lower the risk.

Ex. Wire plugging tool against used battery operated tool

Engineering control : This is applied in the from of barriers and other safeguarding devices, such as GFCI protection, zone differential relaying, energy isolating maintenance switches, high resistive grounding and current limiting devices.

Administrative control : Involves, changes at workplace and using safe work practice to

control the risk.

For example, establishing exclusion zone, use of permits and warning sign.

PPE : In order to minimize the risk of injuries while dealing with electrical works, it is important to wear necessary PPE such as.

Safety System Of Permit To Work

A circuit or item of equipment is isolated
Where appropriate earthed
Where safe for use
Should only be issued by a designated competent person

The information that permit should include are :

Description od the circuit and equipment to be worked on and the location
Name and signature of the permit requester, permit issuer, supervisor, isolation crew etc.
Work equipment
Point of isolation
Location where warning notices are posted
Areas where special safety locks are fitted
The associated hazards
Further precautions to be taken during the course of the work

Inspections and testing OF Electric Tools

Visual Inspection: most defects can be spotted with a simple visual inspection or user check.

Any damage to the lead, including fraying, cuts or heavy scuffing.
Damage to the plug, its cover or pins.
lead that are held together with tape.
Colored wires which are visible where the lead goes into the plug.
Damaged equipment covers, including loose parts or screws.
Sign of overheating, such as scorch mark, melting or staining, check the lead and plug too.

Equipment that has been used or stored in unsuitable conditions, which that might cause fault and If any of the problem are found or suspected

Switch the electrical item off
Report to the supervisor/manager
Don’t repair it on your own
Seek help of a qualified person for

Testing the item
Repairing the damage
Replacement of the item

5. Get the items examined regularly

Maintenance and repair of power tools

Although widely used they can be hazardous and cause potential fatal injuries during use or if not maintained properly.

Step that can be implemented to ensure safety during use and maintenance of such tools are:

The tools need to be examined for defects

Use tools correctly and for their intended purposes only
When working on a circuit, use the approved tools with
insulated handles
Keep tools and cords away from heat, oil and sharp objects
Avoid carrying any tool by the cord
Disconnect cords by pulling the plug instead of the cord

Before cleaning electrical equipment or carrying out any adjustments, maintenance or routine tasks that need to be performed are

Always switch-off and unplug the electrical item
Recognize when the work needs to be done by someone with a full understanding of the risks and requirements, such as a trained and competent electrician – for example, for equipment repairs or alterations to an electrical installation
Do not work on any exposed live parts. A fully trained and competent person should be used, if live parts are exposed that are not made dead.

Conclusion

Electricity can be defined as the flow of charged particles through a conductor, which is also known as an electric current across a particular point, within a specified period of time.
Electric shock is caused by an electric current passing through your body.
The severity of injury is primarily based on three things such as the amount of current flowing through the body, the path of the current through the body and the length of time the body is in the circuit.
Electric arcs generate a very large amount of energy causing ultraviolet radiation in a short period of time, possibly less than a second.
Arc flash occurs when several electrical conductors with significant fault currents flowing through them are placed close to each other.
A circuit breaker is a mechanical device in the form of a switch, which automatically opens when the circuit is overloaded.
LOTO procedure helps to successfully isolate hazardous energy sources and make machines/equipment non-operational, until a task is completed.
An electrical hazard can be defined as a dangerous condition where a worker can make electrical contact with energized equipment or a conductor exposing the worker to injury from electric shock.
Hierarchy of Risk Control is represented by a pyramid comprising risk control measures in the order of decreasing importance.
An electrical permit-to-work is a statement declaring that a circuit or item of equipment is isolated and grounded and where appropriate is safe for maintenance.
Inspection and testing of electrical equipment’s must be carried out only by a competent individual.