Single-line diagram How to represent the electrical installation of a house

WHAT IS A single-line diagram

The single-line diagram is a graphical representation of an electrical installation. It differs from other diagrams because, in the case of the Single Line diagram, each circuit is represented by a single line, in which all the conductors of the corresponding section are represented.

BASIC ELEMENTS OF A SINGLE-LINE DIAGRAM

Following the standard electrical symbolism, the basic elements of the installation will be represented in the single-line diagram. In some of them we could even find more sophisticated elements, more typical of more complex schemes.

DISTRIBUTION PANEL

The distribution panel contains the elements for the protection and control of the electricity supply of the house. The electrical system is organized from this panel and the power of the installation is distributed.

In the single-line diagram the electrical panel is usually represented by a rectangle drawn with a dotted line.

CIRCUITS

A regular house usually has at least 5 circuits. In the single-line diagram we will see them represented as a line in which all the conductors are included.

The top end usually corresponds to the start of the scheme. The lower end is usually connected to another circuit or to a receiver.

• First circuit: controls lighting and illumination (intensity 10A)
• Second circuit: shows most of the plugs (16A current)
• Third circuit: represents the kitchen and bathroom sockets (intensity 16A)
• Fourth circuit: for the oven (intensity 25A)
• Fifth circuit: it brings together the washing machine and washing appliances (intensity 20A)

ELECTRICAL RECEIVERS

Electrical receivers represent all devices that are plugged in, whether they are thermal, such as stoves, irons, ovens, etc.; or luminous, such as lamps

POWER CIRCUIT BREAKER

The function of the Power Circuit Breaker is cutting off the flow of electricity to the installation in the event of a short circuit or an overvoltage. This switch monitors that the maximum bearable by the installation is not exceeded

RESIDUAL-CURRENT DEVICE

Its function can be confused with that of the IGA, since the Residual-Current Device also cuts off the installation, but for a different reason. The Residual-Current Device is responsible for protecting the installation against possible current leaks.

In the case that you cut off the installation, this will be because of an earth leak or because some electrical appliance is defective

MINIATURE CIRCUIT BREAKER (MCB)

MCBs are responsible for protecting electrical circuits against overloads and short circuits. They have:

• A magnetic trigger that is activated when the current exceeds its nominal value
• A thermal disconnector, which disconnects the electrical flow if it overheats.

DISTRIBUTION BOARD

It is in the Distribution board where the safety, control and protection elements are located. It is normally close to the access door to the house