Appendix E 5.2 Cable Connection Design
The cable layout for the intersection is prepared next, according to the general requirements indicated in Appendix F. The layout, which uses the open-loop system, is shown in Figure E 14. Two parallel circuits are set up to connect all signal faces and pedestrian push-buttons to the controller.
A closed-loop system may be achieved by adding a cable between Posts 4 and 5. This helps to restore the service quickly in the event of a breakage elsewhere in the loop. However, this cable would not normally be terminated at Post 5 as it would affect the lamp monitoring.
The vehicle detectors are connected to the controller separately via screened feeder cables. The cable size is chosen to provide sufficient cores to cater for signal requirements with adequate spares.
The circuits are arranged to achieve the most economical solution in terms of cable size and length, and the associated costs of ducting under the prevailing site conditions and existing services. Adequate spares in cores must be provided in each cable for possible future expansion. The cable size is chosen to provide sufficient cores to cater for signal requirements with adequate spares.
In view of the above considerations, the first circuit caters for Posts 1 to 4; the second circuit caters for Posts 5 to 10.