For the purposes of the following provisions, electrical brakes are service braking systems consisting of a control device, an electromechanical transmission device, and friction brakes. The electrical control device regulating the voltage for the trailer shall be situated on the trailer.

The electrical energy required for the electrical braking system shall be supplied to the trailer by the motor vehicle.

Electrical braking systems shall be actuated by operating the service braking system of the motor vehicle.

The nominal voltage rating shall be 12 V.

The maximum current consumption shall not exceed 15 A.

The electrical connection of the electrical braking system to the motor vehicle shall be effected by means of a special plug and socket connection corresponding to …55, the plug of which shall not be compatible with the sockets of the lighting equipment of the vehicle. The plug together with the cable shall be situated on the trailer.

If there is a battery on the trailer fed by the power supply unit of the motor vehicle, it shall be separated from it supply line during service braking of the trailer.

With trailers whose unladen mass is less than 75 % of their maximum mass the braking force shall be automatically regulated as a function of the loading condition of the trailer.

Electrical braking systems shall be such that even if the voltage in the connection lines is reduced to a value of 7 V, a braking effect of 20 % of the (sum of the) maximum stationary axle load(s) shall be maintained.

Control devices for regulating the braking force, which react to the inclination in the direction of travel (pendulum, spring-mass-system, liquid-inertia-switch) shall be attached to the chassis if the trailer has more than one axle and a vertically adjustable towing device. In the case of single-axle trailers and trailers with close-coupled axles where the axle spread is less than 1 metre, these control devices shall be equipped with a mechanism indicating its horizontal position (e.g. spirit level) and shall be manually adjustable to allow the mechanism to be set in the horizontal plane in line with the direction of travel of the vehicle.

The relay for actuating the braking current in accordance with point 2.2.1.20 of Annex I, which is connected to the actuating line, shall be situated on the trailer.

A dummy socket shall be provided for the plug.

A tell-tale shall be provided at the control device, lighting up at any brake application and indicating the proper functioning of the trailer electrical braking system.

Electrical braking systems shall respond at a deceleration of the tractor/trailer combination of not more than 0,4 m/s².

The braking effect may commence with an initial braking force, which shall not be higher than 10 % of the (sum of the) maximum stationary axle load(s) nor higher than 13 % of the (sum of the) stationary axle load(s) of the unladen trailer.

The braking forces may also be increased in steps. At higher levels of the braking forces than those referred to in point 3.2 these steps shall be not higher than 6 % of the sum of the maximum stationary axle loads, nor higher than 8 % of the (sum of the) stationary axle load(s) of the unladen trailer. However, in the case of single-axle trailers having a maximum mass not exceeding 1,5 tonnes, the first step shall not exceed 7 % of the sum of the maximum stationary axle loads of the trailer. An increase of 1 % of this value shall be permitted for the subsequent steps (e.g. first step 7 %, second step 8 %, third step 9 %, etc.; any further step should not exceed 10 %). For the purpose of these provisions a two-axle trailer having a wheelbase shorter than 1 metre shall be considered as a single-axle trailer.

The prescribed braking force of the trailer of at least 50 % of the maximum total axle load shall be attained — with maximum mass — in the case of a mean fully developed deceleration of the tractor/trailer combination of not more than 5,9 m/s² with multi-axle trailers. Trailers with close-coupled axles where the axle spread is less than 1 metre shall also be considered as single-axle trailers within the meaning of this provision. Moreover, the limits as defined in the Appendix to this Annex shall be observed. If the braking force is regulated in steps, they shall lie within the range shown in the Appendix to this Annex.

The test shall be carried out with an initial speed of 60 km/h.

Automatic braking of the trailer shall be provided in accordance with the conditions of point 2.2.2.9 of Annex I. If this automatic braking action requires electrical energy, a trailer braking force of at least 25 % of the maximum total axle load shall be guaranteed for at least 15 minutes to satisfy the abovementioned conditions.