Fuses and circuit breakers

All circuits shall be protected by fuses or automatic circuit breakers, except for the following:
- From the starter battery to the cold start system;
- From the starter battery to the alternator;
- From the alternator to the fuse or circuit breaker box;
- From the starter battery to the starter motor;
- From the starter battery to the power control housing of the endurance braking system (see, if this system is electrical or electromagnetic;
- From the starter battery to the electrical lifting mechanism for lifting the bogie axle.
The above unprotected circuits shall be as short as possible.



Battery terminals shall be electrically insulated or the battery shall be covered by an insulating cover.
Batteries which may develop ignitable gas and are not located under the engine bonnet, shall be fitted
in a vented box.


Light sources with a screw cap shall not be used.

Electrical connections between motor vehicles and trailers

Electrical connections shall be designed to prevent:
- Ingress of moisture and dirt; the connected parts shall have a protection degree of at least IP
54 in accordance with IEC 60529;
- Accidental disconnection; connectors shall fulfil the requirements given in clause 5.6 of
ISO 4091:2003.

Requirements of are deemed to be met:
- for connectors standardized for specific purposes according to ISO 12098:20041, ISO
7638:20031, EN 15207:20141 or ISO 25981:20081
- where the electrical connections are part of an automatic coupling system (see ECE
Regulation No.552).

Electrical connections for other purposes concerning the proper functioning of the vehicles or their
equipment may be used provided they comply with the requirements of


The nominal voltage of the electrical system shall not exceed 25V A.C. or 60V D.C.
Higher voltages are allowed in galvanically isolated parts of the electrical system provided those parts
are not located within a perimeter of at least 0.5 metres from the outside of the load compartment or
Additionally systems working on a voltage higher than 1000V A.C. or 1500V D.C. shall be integrated
in an enclosed housing.
If Xenon lights are used only those having integrated starters are allowed.
1 ISO 4009, referred to in this standard, need not be applied.
2 ECE Regulation No. 55 (Uniform provisions concerning the approval of mechanical coupling components of
combinations of vehicles).

Battery master switch

A switch for breaking the electrical circuits shall be placed as close to the battery as practicable. If a
single pole switch is used it shall be placed in the supply lead and not in the earth lead.

A control device to facilitate the disconnecting and reconnecting functions of the switch shall be
installed in the driver's cab. It shall be readily accessible to the driver and be distinctively marked. It
shall be protected against inadvertent operation by either adding a protective cover, by using a dual
movement control device or by other suitable means. Additional control devices may be installed
provided they are distinctively marked and protected against inadvertent operation. If the control
device(s) are electrically operated, the circuits of the control device(s) are subject to the requirements

The switch shall break the circuits within 10 seconds after activation of the control device.

The switch shall have a casing with protection degree IP 65 in accordance with IEC Standard 60529.

The cable connections on the switch shall have protection degree IP 54 in accordance with IEC 60529.
However, this does not apply if these connections are contained in a housing which may be the battery
box. In this case it is sufficient to insulate the connections against short circuits, for example with a
rubber cap.

Permanently energized circuits

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