Electricity Safety Precautions and First Aides

SAFETY PRECAUTIONS AND FIRST AIDES

As a source of power, electricity is used in all aspects of life. In the home and at work, electricity provides the power for everything from domestic appliances to industrial machines, from office equipment to electric tools. When compared to the potential dangers of machinery and chemical substances, electrical hazards can be easily overlooked. Unfortunately, this neglect often causes serious accidents and loss of property. Many of these accidents can be prevented as they are mainly caused by electricity users who lack basic safety awareness.

Electrical safety legislation

The legislation involving electrical safety is the "Electricity Ordinance (Chapter 406)" as enforced by the Electrical and Mechanical Services Department and "Factories and Industrial Undertakings (Electricity) Regulations (Chapter 59)" enforced by the Labour Department. 2.1 Electricity Ordinance The Ordinance requires that people engaged in electricity work, or with contractors and electricity generation facilities, must be registered. It also stipulates the safety requirements of electricity supply, electricity wiring and electrical products, etc. There are several subsidiary regulations of the Electricity Ordinance, including: 1. Electricity Supply Regulations 2. Electricity Supply (Special Areas) Regulations 3. Electricity (Exemption) Regulations 4. Electricity (Registration) Regulations 5. Electricity (Wiring) Regulations 6. Electrical Products (Safety) Regulation 7. Electricity Supply Lines (Protection) Regulation.

Factories and Industrial Undertakings (Electricity) Regulations The Regulations apply to industrial undertakings in which electricity is generated, transformed, distributed or used. The purpose is to supervise the safety of electrical facilities and working processes, etc. of relevant industry.

1. Electrical hazards

Electric shock refers to the electricity passing through the human body, affecting the normal function of the heart, lungs and nervous system. Ventricular fibrillation caused by electricity is the main reason for death from electric shocks. Electric shocks may indirectly lead to accidents, e.g. falling from heights and bruising due to body trauma etc. Ventricular fibrillation involves a series of disordered contractions of the heart's ventricular muscle fibres, which prevents regular heartbeat. Under normal conditions, the human heart rate is from around 60 to 100 times per minute. During an electric shock, heartbeat may increase up to several hundred times per minute. When the heart cannot sustain such rapid contraction and relaxation, it may stop beating and cause death.

The effect of currents passing through various parts of the body

2. Burns

During an electric shock, the current passing through the body may lead to burns on the skin, muscles or internal organs. As electric shocks and burns are closely related, preventative measures should be considered together.

3. Fires and explosions

High temperatures caused by currents under abnormal conditions, may result in accidental fires and explosions. The common causes leading to high temperatures include:

a. Overloading of electricity

b. Insulator breakdowns or short circuits.

c. Improper contact of electrical circuit

d. Improper maintenance of electrical appliances or wiring

e. Poor ventilation, etc.

If flames, sparks or metallic solutions due to electric arc welding are not controlled, hazardous fires or explosions can occur.

4. Special process (electric arc welding)

Electric arc welding is commonly used for metallic welding and cutting. The various hazards from welding or cutting include the following:

Hazards

Burns

Sparks or hot metal fragments from arc welding or cutting may result in serious burns. Proper protection is essential.

Radiation

If proper eye protectors are not used while welding or cutting, radiation or other objects may hurt the welder.

Safety measures: Wear proper personal protective equipment, e.g. approved eye protectors, hand shields, leather aprons, leather gloves and safety shoes, etc.

Electric shock It is dangerous to conduct the arc welding in a wet environment or on rainy days. Safety measures:

a. Avoid electric welding in such conditions.

b. Earth the tools and equipment properly.

c. Adjust the current required for welding to the minimum amount.

d. Add an automatic voltage regulator to reduce the open-circuit no-load voltage orosis of the transformer output, reducing the chance of getting an electric shock.

Poisonous fumes and gases

Inhalation of poisonous fumes and gases during welding or cutting may cause serious health problems. Safety measures:

a. Provide adequate ventilation.

b. Use exhaust systems to remove poisonous fumes and gases.

Protective measures for prevention of direct electrical contact

The following procedures will prevent the human body from contact with electrical conductors, wiring, electrical sources, etc.

Protective measures

Insulation

Shield the electrical conductor with an insulator to prevent direct contact

Obstacles

Place obstacles to prevent any accidental contact with the electrical conductor

Barriers or enclosures

Create barriers or enclosures that prevent any direct contact with the electrical conductor

Placing out of reach

This prevents accidental contact with the electrical conductor

Safety devices

1. Fuse

Normally, a fuse is a copper wiring with a set current fusion value. If the current exceeds the set fusion value, the fuse will blow and the current is cut-off, thus preventing overloading.

A fuse must be installed on "live" wires. When replacing a fuse, the new fuse must be same current fusion value as the old one.

2. Circuit breakers (MCB)

Circuit breakers are based on the principle of the electromagnetic field. The current entered may enable the coils of the circuit breaker to magnetize. When the current exceeds the set value (i.e., Overloading), the magnetization intensifies, switching off the circuit breaker and disconnecting the electric source.

3. Earthing

Earthing provides a low resistance way of discharging electricity to the ground in case of current Leakage. This means that during an electric shock, the current passes through the "earth" wire and is prevented from entering the human body and causing injury.

Safe use of electricity

1. Safe use of plugs

Specification of electric plugs

Plugs for electrical equipment shall match the power/current rating (calculated by voltage 220V).

2. Connection of plugs

Electrical and Mechanical Services Department announced the new colour code for those electrical installation works on or after 1 July 2007. From now on, new colour code should be used for all new electrical installation works.

Brown or red to Live (L)

Blue or black to Neutral (N)

Yellow/green or green to Earth (E or )

3. Safety hints

i) Use correct plugs. Never insert the core of the cord directly into a socket.

ii) Unplug by pulling the plug - not the cord.

iii) Do not touch the plug with wet hands, as wet skin reduces the resistance of the body, resulting in more serious injuries.

iv) Broken plugs must be replaced immediately.

v) Avoid overloading! Never put too many plugs into the same socket.