BS AU 198:1984 download free.Electrical connections between towing vehicles and trailers with 24 V electrical equipment: type 24 S (supplementary).
1 Scope
BS AU 198 specifies requirements for sockets and plugs of type 24 S which will permit electrical connections between towing vehicles and trailers with 24 V electrical equipment.
NOTE I These sockets and plugs are not interchangeable with type 24 N (normal) sockets and plugs (see 138 AU 197). NOTE 2 The titles of the publications referred to in this standard are listed on the inside back cover.
2 General
2.1 Number of contacts. There shall be seven contacts designated as follows:
1common return;
2 failure warning:
3 reversing light;
4 power supply;
5 sensing device with common return:
6 switched power supply;
7 rear fog light.
2.2 Arrangement of contacts. The arrangement of contacts shall be as shown in Figure 1 and Figure 2.
2.3 Socket. The socket shall be mounted on the rear of the towing vehicle in the case of a road train. It shall he mounted on the semi-trailer in the case of an articulated road train.
The socket shall be provided with six contact pins (2 to7 ) and one spring tube (1) corresponding to pin 1 of the plug.
All contacts shall be insulated.
NOTE After fitting, contact 1 may be connected to the common return of the vehicle.
The internal diameter of tube 1 shall be such that the corresponding pin of the plug can be connected with a moderate push, but it shall ensure a good electrical contact.
Each rear terminal shall be capable of receiving two conductors of 1.5 mm2 minimum cross section.
The contact designations shall be permanently marked on the inside of the socket cover and on the terminal face in symbols not less than 2 mm high.
NOTE These symbols, which need not be numbers. may differ from those indicated in Figure 1, provided that the specified pin locations of the different functions are complied with.
The socket shall be provided with a splashproof cover which shall close automatically when the plug is disengaged. The hinged cover on the socket shall be provided with a locking lug to retain the plug when it is engaged.
All metallic parts of the socket shall be made of corrosion-resistant material or shall be protected against corrosion.
2.4 Plug. The plug shall be mounted on the trailer in the case of a road train and on the towing vehicle in the case of an articulated road train.
The plug shall be provided with six spring tubes corresponding to pins 2 to 7, and one contact
pin 1.
The internal diameter of tubes 2 to 7 shall be such that the corresponding pins of the socket can be connected with a moderate push, but they shall ensure a good electrical contact.
Each rear terminal shall be capable of receiving one conductor of 2.5 mm2 minimum cross section. The contact designations shall be permanently marked on the terminal face in symbols not less than 2 mm high.
NOTE These symbols, which need not be numbers, may differ from those indicated in Figure 2. provided that the specified pin locations of the different functions are complied with.
All metallic parts of the plug shall be made of corrosion-resistant material or shall be protected against corrosion.
Means of fixing and sealing the cable shall be provided.
2.5 Allocation of cable colours. The cable colours of the seven-core connecting cable shall be allocated to the different circuits as shown in Table 1.
2.6 Distinguishing marking. A light and permanent colour shall be used for at least the insulating parts of the 24 S connector, to distinguish it from the 24 N connector.
NOTE BS AU 197 specifies that the 24 N connector is a dark and permanent colour, preferably black.
2.7 Dimensions for socket and plug. The dimensions for the socket and plug shall be as shown in Figure 1 and Figure 2. The clearance dimensions around the socket and plug assembly shall be as shown in Figure 3.
The location of the socket and plug assembly on the towing vehicle shall be as in BS AU 195.
3 Performance
The performance of connectors shall comply with BS AU 194.