Work instruction
NR/WI/TEL/00113
Wiring of Copper Telecoms Terminations (formerly RT/E/WI/00113)
Issue 1, April 2005
Work instruction for copper cable terminations, MDF and lineside frame labelling and circuit jumpering: the jumper wire colour code by circuit type, A-leg/B-leg convention, temporary jumpers, circuit cessation and vertical/level numbering on new frames
Clause map — what each clause deals with
| 1.1 | Definitions & Abbreviations | Terms used, including frame (MDF, IDF, DP), through jumper and temporary jumper owner |
| 2 | Purpose | Sets the basic principles for copper cable terminations, frame labelling and circuit jumpering, replacing three withdrawn Railway Group Standards |
| 3 | Wiring and Termination Procedures | What makes a termination safe: deal with unterminated jumpers, recover redundant jumpers at MDFs (leave intermediate through jumpers), update records, right tools, colour-coded jumper wire |
| 3.1 | Cable Terminations | All pairs of a copper cable go on a frame; any pairs that can't be terminated are isolated and capped at both ends |
| 3.2 | Signalling & SCADA Circuits in Telecom Cables | Signalling and SCADA circuits must be identifiable at every intermediate point, using red markers on the terminations |
| 3.3 | Temporary Jumpering | Temporary jumpers are installed to the same standard as permanent ones, labelled as temporary with owner and job details, and removed before the job is closed |
| 4.1 | Wrong Side Failure | Work on telecoms cables can affect signalling circuits, so the risk of a wrong side failure must be considered |
| 4.1.1 | Un-terminated or Unprotected Wires | Loose wires found during work are made safe: jumpers recovered, cable wires capped and left tidy |
| 4.2 | Circuit Cessation | When a circuit is ceased, recover the jumpers at the end frames; leave intermediate through jumpers for reuse |
| 4.2.1 | Cessation of Switching and Transmission Circuits | For switching, data and transmission circuits, also recover the equipment room jumpers and set the equipment port to spare |
| 5 | Numbering of Telecoms MDF and Lineside Terminations | Applies to new single- and double-sided frames; extensions to existing frames carry on the existing scheme |
| 5.1.1 | Labelling on a Single Sided Distribution Frame | How verticals are lettered on a single-sided frame and how added verticals are lettered |
| 5.1.2 | Labelling on a Double Sided Distribution Frame | Front and rear verticals get separate front/rear letters (AF, AR style) |
| 5.1.3 | Double-Sided Frames Within Lineside Cabinets | Which side of a lineside cabinet counts as the front |
| 5.2 | Labelling the Termination Blocks on the Vertical | Each strip or block on a vertical is a numbered level; every level position gets a number even if empty |
| 5.3 | Cable Termination Order and Termination Labelling | Where pair one goes on a block, keep a cable on one vertical, and the minimum cable label details |
| 6 | Jumper Wire | The jumper wire product to use (0.5 mm conductor) |
| 6.1 | Jumper Wire Colour Code General Telecomms | The jumper wire colour code: which colour pair to use for general telecoms, circuits of special importance and 4-wire transmission circuits |
| 6.1.1 | Through Jumpering | Which colour to use for through jumpering at intermediate locations |
| 6.2 | Jumper Wire A-leg and B-Leg | Which colour is the A leg (or positive leg), including at a cross-over |
| Appendix A | Circuits Designated as Special Importance | The list of circuit types treated as special importance (signalling, SCADA, train describers, level crossing phones and similar) |