02-07-2024

UNIT-2
ELECTRICAL HAZARDS, SAFETY
MEASURES & SYMBOLS

UNIT-2
ELECTRICAL HAZARDS, SAFETY MEASURES & SYMBOLS

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 Electrically powered equipment can pose a significant hazard to workers, particularly when mishandled or not
maintained. Many electrical devices have high voltage or high-power requirements, carrying even more risk.
Electrical hazards
Primary Hazards
1.Electric shock
2.Electric fire & explosion
3.Electric flash
4.Electric burns
Secondary Hazards
1.Person falling from height
2.Dropping of tools and object

Electrical Shock Hazard

 The major hazards associated with electricity are electrical shock, fire and arc flash. Electrical shock occurs when the body
becomes part of the electric circuit, either when an individual comes in contact with both wires of an electrical circuit, one
wire of an energized circuit and the ground, or a metallic part that has become energized by contact with an electrical
conductor.
 The severity and effects of an electrical shock depend on a number of factors, such as the pathway through the body, the
amount of current, the length of time of the exposure, and whether the skin is wet or dry. Water is a great conductor of
electricity, allowing current to flow more easily in wet conditions and through wet skin.
 The effect of the shock may range from a slight tingle to severe burns to cardiac arrest. The chart below shows the general
relationship between the degree of injury and amount of current for a 50-cycle hand-to-foot path of one second's duration of
shock. While reading this chart, keep in mind that most electrical circuits can provide, under normal conditions, up to 20,000
milliamperes (or 20Amps) of current flow.

Path of the current flow

The two most dangerous paths that current can take through human body are (1) from hand to
hand and (2) from left hand to either foot. The second path is the most dangerous since the
current will flow through both the heart and other vital organs. Path created through head also
has an increased chance of death.

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FALLS HUMAN SAFETY IN THE USE OF ELECTRICITY SYSTEM

Ensuring human safety when using electricity is of paramount importance, as electricity can be extremely dangerous if
mishandled. Here are some key safety measures and tips to follow when using an electrical system:
1. Proper Installation: Electrical systems should be installed by qualified professionals according to local building codes and
regulations. This includes wiring, outlets, switches, and circuit breakers. DIY electrical work can lead to serious hazards.
2. Grounding: All electrical systems should be properly grounded to redirect excess electricity safely into the ground in case of
a fault. This helps prevent electrical shocks.
3. Circuit Breakers and Fuses: Ensure that circuit breakers and fuses are correctly sized for the circuits they protect. They
should trip or blow in the event of an overload or short circuit, preventing fires and electrical shocks.
4. GFCI Outlets: Ground Fault Circuit Interrupter (GFCI) outlets should be used in areas where water is present, such as
kitchens, bathrooms, and outdoor outlets. GFCIs can quickly detect and shut off power if they sense a ground fault, reducing
the risk of electric shock.
5. Outlet Covers: Use outlet covers or safety caps in homes with young children to prevent them from inserting objects into
outlets.
6. Extension Cords and Power Strips: Do not overload extension cords or power strips. Follow the manufacturer's
recommendations for maximum load capacity. Never use damaged cords or outlets.
7. Water and Electricity: Keep electrical appliances and equipment away from water sources. Do not use electrical appliances
when you are wet, and never touch electrical switches or outlets with wet hands.
8. Appliance Safety: Regularly inspect appliances for frayed cords or exposed wires. Replace or repair damaged cords
immediately. Unplug appliances when not in use.

9. Space Heaters: When using space heaters, keep them at least three feet away from flammable materials and never leave them
unattended. Plug them directly into an outlet, not an extension cord.
10. Outdoor Electrical Safety: Use outdoor-rated extension cords and outlets for outdoor activities. Ensure that they are
protected from the weather.
11. Electrical Fires: In case of an electrical fire, do not use water to extinguish it. Use a Class C fire extinguisher or call the fire
department.
12. Education: Teach family members about electrical safety, especially children. Make sure they understand the dangers of
electricity and how to use electrical devices safely.
13. Electrical Inspections: Periodically have a qualified electrician inspect your electrical system to check for any potential
issues or hazards.
14. Emergency Shut-off: Know the location of your electrical panel (breaker box) and how to shut off the power in case of an
emergency.
15. Respect Warning Signs: Pay attention to warning signs and labels on electrical equipment and appliances. They provide
essential safety information.
16. Electrical Safety Equipment: Consider using surge protectors to safeguard sensitive electronic equipment from power
surges and invest in a smoke detector and carbon monoxide detector to provide early warning in case of electrical or other
hazards.
Following these safety measures can significantly reduce the risk of electrical accidents and promote a safe environment when
using electricity systems. Always prioritize safety and seek professional help when needed.

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CPR- Cardio Pulmonary Resuscitation

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SAFETY MEASURES OF PERSONNEL TO AVOID ELECTRIC SHOCKS

Preventing electric shocks is crucial for the safety of personnel working with or around electricity. Here are safety measures and
guidelines to help avoid electric shocks:
1. Training and Education:
 Ensure that personnel receive proper training on electrical safety, including understanding the hazards associated with
electricity and how to work safely with electrical equipment.
2. Personal Protective Equipment (PPE):
 Personnel should wear appropriate PPE, such as insulated gloves, safety glasses, and flame-resistant clothing, when
working with electricity or electrical equipment.
3. Lockout/Tagout (LOTO):
 Implement and follow lockout/tagout procedures when working on electrical equipment to ensure that power sources are
properly de-energized and locked or tagged out to prevent accidental energization.
4. Qualified Personnel:
 Only qualified electricians or individuals with the necessary training and expertise should perform electrical work.
Unqualified personnel should not attempt electrical repairs or modifications.
5. Electrical Tools and Equipment:
 Use insulated tools and equipment designed for electrical work. Ensure that they are in good condition and regularly
inspected for defects.

6. Ground Fault Circuit Interrupters (GFCIs):

 Install GFCIs in areas where electrical equipment may come into contact with water to provide extra protection against
electric shock.
7. Inspect Cords and Plugs:
 Regularly inspect power cords, plugs, and connectors for damage. Replace any damaged cords or connectors immediately.
8. Keep a Safe Distance:
 Maintain a safe distance from electrical equipment when it is in operation. Avoid reaching into live electrical panels or
equipment.
9. De-energize Before Servicing:
 Always turn off and de-energize electrical equipment before servicing or making repairs. Verify that the equipment is de-
energized with a voltage tester before touching it.
10 One Hand Rule:
 When working on live electrical circuits, use the "one hand rule." Keep one hand in your pocket or at your side to reduce
the chance of completing a circuit through your body.
11 Residual Current Devices (RCDs):
 Use RCDs or similar devices that can quickly disconnect the power supply if a fault is detected.
12 Avoid Wet Conditions:
 Do not work on electrical equipment in wet or damp conditions unless it is specifically designed and rated for such
environments.

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13. Safe Ladders and Platforms:

 Use non-conductive ladders and platforms when working on elevated electrical equipment or circuits.
14. Stay Informed:
 Keep up to date with safety regulations and best practices in electrical safety. Follow all applicable codes and standards.
15. Emergency Response:
 Have a plan for responding to electrical emergencies, including how to administer first aid and contact emergency services in
the event of an electrical accident.
16. Report Hazards:
 Encourage personnel to report any electrical hazards, damaged equipment, or unsafe conditions immediately so that
corrective action can be taken.
17. Regular Inspections and Maintenance:
 Conduct regular inspections and maintenance of electrical systems and equipment to identify and address potential issues
before they become hazards.
18. Supervision and Accountability:
 Ensure that personnel are held accountable for following electrical safety procedures, and provide supervision as needed,
especially for less experienced workers.
By following these safety measures and promoting a culture of electrical safety in the workplace, personnel can significantly reduce
the risk of electric shocks and create a safer working environment.

Safety symbols
Safety symbols and labels are essential in power control centers (PCC) and motor control centers (MCC) to communicate potential
hazards and safety instructions to personnel working with electrical equipment. Here are some common safety symbols and labels
you might encounter in PCC and MCC installations:
1.Electrical Hazard Symbol:
 Symbol: A lightning bolt inside a triangle with an exclamation mark.
 Meaning: Indicates the presence of electrical hazards, such as the risk of electric shock. It warns personnel to take
appropriate precautions when working on or around electrical equipment.
2.High Voltage Symbol:
 Symbol: A lightning bolt or the letters "HV" in a triangle or circle.
 Meaning: Warns of high voltage conditions, which pose a severe electrical shock hazard. Personnel should be trained and
qualified to work with high voltage equipment.
3.Ground Symbol:
 Symbol: A symbol of a grounded conductor, often with a connection to the earth.
 Meaning: Highlights grounding points or equipment that should be grounded for safety, both for personnel and to prevent
electrical faults.
4.Lockout/Tagout Symbol:
 Symbol: A lock and a tag.
 Meaning: Signifies the need for lockout/tagout procedures. It indicates that a device or equipment must be de-energized,
locked, and tagged before any maintenance or servicing can take place.
5.Emergency Stop Symbol:
 Symbol: A square or circular button with a large "STOP" text.
 Meaning: Identifies the location of emergency stop buttons or switches that can quickly shut down equipment in case of an
emergency or when a hazardous situation arises.

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6.Overcurrent Protection Symbol:

1. Symbol: Usually, a fuse or circuit breaker symbol.
2. Meaning: Indicates the location of overcurrent protection devices, such as fuses and circuit breakers, which are critical for
protecting circuits and equipment from overload and short-circuit conditions.
7.Warning Signs:
1. Various warning signs may include caution labels, signs indicating arc flash hazards, or labels indicating the presence of
specific hazards (e.g., rotating equipment).
8.Equipment Identification Labels:
1. Labels indicating the specific equipment's name, function, and electrical ratings for easy identification and reference.
9.Color-Coding:
1. Color-coded wires, cables, and equipment labels are used to indicate the voltage level and the purpose of specific
components in the PCC and MCC. For example, high voltage conductors may be colored orange, while low voltage
conductors may be black.
10.Grounding and Earthing Labels:
•Labels indicating grounding and earthing points to ensure proper grounding of equipment for safety and electrical integrity.

Safety symbols

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