Electrical Installations: Devices, Control & Protection

1. General Devices, Individual Control, and Protection. Power Control Switch

1.1. Location

The general command and protection devices are located near the lead-in entry point of the local or individual user's dwelling. In homes, commercial, and industrial premises, a sealed box for the power control switch is placed immediately before other devices in a separate compartment. This box may be placed in the same panel as the overall control and protection devices.

In residential units, the overall command and protection devices must be accessible from the front door and not located in bedrooms, bathrooms, or toilets. In industrial or commercial units, they should be placed near the front door.

Individual control and protection devices for internal equipment circuits can be installed in separate panels and other locations.

In public areas, precautions must be taken to prevent public access to control and protection devices.

The height of general and individual control and circuit protection devices, measured from ground level, should be between 1.4 and 2 meters in residential buildings and at least 1 meter in commercial premises.

1.2. Panel Composition and Characteristics

General and individual control and protection devices, positioned vertically, will be housed within one or more distribution boxes from which internal circuits originate.

Panel enclosures must comply with UNE-EN 20451 and 60439-3, with a minimum degree of protection of IP 30 according to UNE 20324 and IK07 according to UNE-EN 50102. The enclosure for the power control switch must be sealed, with dimensions appropriate for the supply type and tariff. Its characteristics and type must correspond to a formally approved model.

The general and individual control and protection devices will include at least:

• An automatic omnipolar cutoff switch with manual operation and overload and short-circuit protection components. This switch will be independent of the power control switch.
• A general residual current device (RCD) for protection against indirect contact in all circuits.
• Omnipolar circuit breakers for overload and short-circuit protection in each internal circuit.
• Surge protection device, according to ITC-BT-23, if necessary.

If the installation type requires RCDs per circuit or circuit group, the general RCD may be omitted if all circuits are individually protected. If multiple circuit breakers are installed in series, selectivity between them must be ensured.

The panel must accommodate the necessary control mechanisms required by the applicable tariff.

1.3. Main Characteristics of Protective Devices

The automatic omnipolar cutoff switch must handle short-circuit currents at the installation point up to at least 4,500 A.

Other circuit breakers and RCDs must withstand potential short-circuit currents at the installation point. The sensitivity of the RCDs must comply with ITC-BT-24.

Overload and short-circuit protective devices within the panel must have the appropriate number of poles to protect the corresponding circuit phases. Their breaking capacity must be suitable for the allowable current of the protected conductors.