Installation Requirements for Electrical Components

Purpose and Scope

1. The purpose of this Instruction is to determine the installation requirements of transformers, autotransformers, reactors, rectifiers, and capacitors. The components covered by this Instruction shall meet the requirements of applicable European Directives as set out in Rule 6 of the Low Voltage Electrotechnical Regulation.

General Installation Conditions

2. Installation of the components covered by this Instruction shall meet, as appropriate, specifications of the premises (or locations) where connections are to be installed. The connections of these components shall be carried out with appropriate connection elements for the materials being joined, i.e., in the case of aluminum windings, with bimetallic connectors. These components shall be installed so that they have adequate ventilation for proper cooling.

Transformers and Autotransformers

2.1. Transformers that may be accessible to non-specialists shall be constructed or located so that their windings and low voltage elements, whichever is higher than 50 V, are permanently inaccessible. The transformers shall not be mounted directly on combustible parts of a building, and where necessary to install next to them, non-combustible screens shall be used as a separation element. The separation between the transformers and these screens shall be 1 cm when the transformer power is less than or equal to 3,000 VA. This distance shall be increased proportionally to the power when it is greater. Transformers in fixed installations, when their power does not exceed 3,000 VA, provided a suitable temperature limiter is included, may be mounted directly on combustible parts. The use of autotransformers shall not be permitted if the two circuits connected to them are not designed for higher insulation voltage. In the case of an autotransformer connection to a power source with a neutral conductor, the winding terminal common to the primary and the secondary shall be connected to the neutral conductor.

Reactors and Rectifiers

2.2. The installation of reactors and rectifiers shall meet the same general requirements as those stipulated for transformers. In relation to rectifiers, the following shall also be taken into account: When the rectifiers are not designed to prevent accidental passage of alternating current fed to the circuit or its return to the AC circuit, a suitable associated device shall be installed to prevent this eventuality. The wiring for currents of different nature shall be different and suitably marked or separated. The circuits for direct current shall be installed following the requirements that apply to their rated voltage.

Capacitors

2.3. Capacitors not marked with a permissible temperature may be used in locations where the ambient temperature is 50 °C or higher. If residual charge on capacitors could endanger people, an automatic discharge device shall be provided or a warning sign indicating the danger shall be placed. Capacitors with flammable dielectric liquid shall meet the same requirements as rheostats and reactors. For the use of capacitors above 2,000 m of altitude above sea level, precautions must be taken according to the manufacturer, as specified by UNE-EN 60831-1. The capacitors must be adequately protected, as they will be used with overcurrent exceeding 1.3 times the current corresponding to the rated voltage at mains frequency, excluding transients. The control devices and protection of the capacitors must withstand in steady state, 1.5 to 1.8 times the rated current assigned to the capacitor in order to take into account harmonics and tolerances on capacitance.

Overcurrent Protection of Transformers

3. Each transformer shall be protected by an overcurrent protective device or other equivalent system. This device shall be in accordance with the characteristics listed on the transformer nameplate and the use of the transformer.