What is meant by electrical installation?

Electrical installation is the process of installing wires or cables and related devices in a building structure. Along with electrical wires, an electrical installation includes installing equipment such as switches, distribution boards, lights, electrical panels, and other components. The electrical installation is carried out by an electrician. An electrician is a trained individual who is specialized in electrical-related works and provides electrical services. When it comes to electrical installations, the electrical code specifies the right wire to be used for installations, this will ensure safety and prevent future fire hazards resulting from short-circuiting and overvoltage.

There are safety standards for wiring installations and design, these are specified according to the operating voltage and current capability. Some environmental conditions such as outside temperature, humidity level, sunlight exposure, and chemical exposure impact the selection of wires and cables. The safety codes related to the wiring are different for different regions and countries. The circuit protection and control standards for a building are based on the building's voltage and current ratings. The International Electrochemical Commission (IEC) lays out standards for the wiring procedures in different countries.

In this article, a basic introduction about the electrical installation procedures has been provided. Some of the basic procedures of wiring are also introduced.

Electrical wire color coding and labeling

A thorough understanding of the color-coding of wires ensures consistency of the wiring systems and the electrical circuit, it also provides information about what purpose the wiring is used. The color coding is used both on the outer sheathing of the cables and on the individual cables present inside the outer sheathing. The color-coding indicates the size and Ampere rating of the wires. For example in a three-phase wiring system red, yellow, and green colors are extensively used. Similarly, black wires are sometimes used to indicate hot connections, while the earthing wires are indicated by white color.

Just like the color codes provide information about the nature of the electrical signal the wire is intended to carry, the labeling provides information regarding the wire material, size, and insulation. This information is printed on the outer sheathing of the wire insulating material. The label also provides information about the number of inner wires and also provides any special features such as power rating.

Electrical installation components

In this section, some of the commonly used important electrical components are discussed. These components form the vital add-ons in any electrical installation.

Miniature circuit breakers (MCB)

The MCBs are designed for the building from overloading and excess power. MCBs consist of multiple switches with relays. During a short circuit, the excess power results in the energization of the coils in the relays. The relay pulls back the main power switch thus breaking the electric current flow in the building. The MCBs provide a much safer operation than the electrical fuses.

Switches

Switches are important electrical components, whose main job is to break or complete an electrical circuit. A switch in the 'OFF' condition does not allow an electric current to pass, while the 'ON' condition permits the flow of current. Some of the different kinds of switches are:

• Surface switch
• Flush switch
• Ceiling switch
• Pull switch
• Push-button switch, and
• Bed switch

Electrical conduits

The primary role of electrical conduits is to protect the electrical wiring in an electrical installation. There are various materials by which an electrical conduit is made like plastic, metal, rubber. These conduits can be either flexible or rigid. The electrical conduit wiring is carried by an electrician following safety standards and they are best suited for residential and commercial buildings.

Electric meter

Electric meters are small solid-state devices that have a small needle installed inside them. These devices are used to map the amount of electricity consumed by individuals. The amount of consumed electrical power is indicated by the needle movement.

Fuse

A fuse is a small piece of electrical equipment that has a wire mounted on it. The wire essentially has a lower melting point and of certain electrical resistance. When the rated power exceeds a certain amount, the wires get heated due to their resistance value and melts. The melting of the wire cuts off the current flow thus safeguarding the entire building.

Distribution box

The distribution box is an important device that distributes the electricity coming from the electrical substations to the entire building. It houses three additional components they are:

• Main switch or MCCB (Molded case circuit breaker)
• MCB
• Trip switch or RCCB (Residual current circuit breaker)

Busbars

An electrical busbar is a metallic strip that is generally used in electrical power distributions. This metallic strip is usually housed inside busways, switch gears, panel boards, and busway enclosures. These equipment are usually used for local high power distributions. The busbars are also used to connect low voltage equipment in battery banks and high voltage equipment at electrical switchyards. These are connected by insulated pillars and have sufficient stiffness. They primarily remain open to the ambient air to permit cooling. Copper and aluminum are two of the commonly used metals used in the construction of busbars. There are various types of busbars arrangements they are:

• Single busbar
• Main and transfer type
• Double busbar double breaker
• One and a half breaker
• Mesh arrangement
• Ring arrangement
• Single busbar with bus sectionalized

Context and Applications

The topic is taught in many undergraduate and postgraduate degree courses like:

• Bachelors of Technology (Electrical Engineering)
• Bachelors of Technology (Electrical and Electronics Engineering)
• Bachelors of Technology (Electronics Engineering)
• Master of Technology (Electrical Engineering)

Practice Problems

Q 1. What is the function of the busbar?

1. To carry high voltage
2. They are used for power distribution purpose
3. They are used for equipment colling
4. Both a and b

Answer: Option d

Explanation: Busbars are electrical equipment that is intended to carry high voltage and they are usually meant for high power distributions.

Q 2. What is the abbreviation for IEC?

1. International Electric Commission
2. International Electronic Commission
3. International Electo-mechanical Commission
4. International Electrochemical Commission

Answer: Option d

Explanation: The correct abbreviation for IEC is International Electrochemical Commission.

Q 3. Which professional performs electrical installation?

1. Electrical contractors
2. Electrician
3. Both a and b
4. Construction workers

Answer: Option c

Explanation: The electrical contractors are hired by the building construction firms. Electrical contractors along with electricians perform electrical installation services in various building complexes. They also provide electrical services for private residential houses.

Q 4. What is the abbreviation of RCCB?

1. Residual current circuit breaker
2. Resistant current circuit breaker
3. Residual current circuit barrier
4. Resistance current circuit barrier

Answer: Option a

Explanation: The correct abbreviation for RCCB is a residual current circuit breaker. It is one of the primary components of a distribution box.

Q 5. Which of the following component has a low melting point wire?

1. MCB
2. Fuse
3. Busbar
4. Switchgear

Answer: Option b

Explanation: The fuse is one such electrical component that has a conductive wire primarily made of low melting material. During short-circuit, the wire melts and cuts off the power flow.