STANDARD FOR TELECOMMS WIRING AND TERMINATIONS

Transcription

1 GTlEH H802 Date MR 94 Paae I Part Synopsis This standard defines the Board's policy for the maintenance of Telecomms cable terminations. lthough the standard is centered on maintenance issues its provisions apply equally to new installations STNDRD FOR TELECOMMS WIRING ND TERMINTIONS pproval and uthorisation Signatures removed from electronic version Submitted by: NordMated Responsible Manager pproved by: Chairman, S&T Engineering Subject Committee uthorised by: Board Member, Engineering Controlled Copy No This document is the property of the British Railways Board. It shall not be reproduced in whole or in part, nor disclosed to a third party, without the written permission of the Director, Engineering Standards Published by Group Standards Macmillan House Copyright l994 British Railways Board GROUP STNDRDS

2 GT/EH H802 Date MR 94 2 Withdrawn Document STNDRD FOR TELECOMMS WIRING ND TERMINTIONS ISSUE/REVISION RECORD SUPPLY This standard will be updated when necessary by distribution of a complete replacement. mended or additional parts of revised pages will be marked by a vertical black line in an adjacent margin. ISSUE REVISION DTE COMMENTS 1 Mar 94 New Document. This document contains 7 pages. RESPONSIBILITIES ND DISTRIBUTION This standard shall be worked to by anyone responsible for the installation and maintenance of infrastructure telecomms cable terminations. Controlled copies of this standard will be distributed by Group Standards to: S&T Engineer, InterCity S&T Engineer, Regional Railways Network S&T Engineer S&T Engineer, Railfreight Distribution S&T Engineer, Trainload Freight Director TQM, BRT Ltd. Director TQM, Central Services Managing Director, Rail Express Parcels Director Railways, BR Crossrail Team Engineering Manager, Union Railways Ltd. Deputy Managing Director, EPS Ltd. Director Business Review Document Control Manager, Railtrack Controlled copies of this standard must be made available by the businesses ot all S&T Engineers who manage/supervise engineering or technical activities. IMPLEMENTTION The provisions in this standard are mandatory. Part B: Sections 4 and 6 shall be implemented retrospectively where an existing practice allows easy adaption. Controlled and uncontrolled copies of this standard may be obtained from the Documentation Manager, Infrastructure Support Group, CP 15, Room E104, Macmillan House, Paddington Station, London W2 1FT Tel. No BR , BT Fax No BR BT TBLE OF CONTENTS Section Description Part Synopsis pproval and uthorisation Issue/ Record Responsibilities and Distribution Implementation Supply Table of Contents Part B B1 1 Purpose B1 2 Scope B1 3 Wiring and Termination procedures B1 4 Procedures for Working on Telecommunication Cables B2 5 Numbering of Telecommunications MDFs and Lineside Terminations B3 PPENDICES ppendix B4 ppendix B B4 ppendix C B5 Staff who are not issued with a personal copy of this standard but whose duties require access to a copy, must be briefed about this standard.

3 STNDRD FOR TELECOMMS WIRING ND TERMINTIONS GT/EH H802 Date MR 94 B1 Part B 1 PURPOSE 1.1 The purpose of this standard is to ensure that all staff who have a management responsibility for the installation and maintenance of infrastructure telecommunications cables are aware of the fundamental principles that must be adhered to. 1.2 The application of these principles will ensure that the termination of cables, wires and jumpers, whether permanent or temporary, produces a safe and satisfactory connection that will prevent any possible contact or interference with other working circuits. 1.3 This standard includes a standard system of labelling and numbering of terminations that shall be applied to all new installations of main distribution frames (MDFs) and lineside location cases, and also to incorporate the additional marking of signalling and electrification supervisory circuits. 2 SCOPE nyone responsible for the installation and maintenance of infrastructure telecommunication cables shall comply with this standard. 3 WIRING ND TERMINTION PROCEDURES 3.1 The areas that must be considered in ensuring an inherently safe cable termination are as follow: The immediate identification of unterminated jumpers to establish their function followed by either recovery or reinstatement to the correct position once verification has been assured The recovery of jumpers of redundant circuits from all MDFs in order to avoid any future confusion. Through jumpering at intermediate line side locations must be left intact for future use and to facilitate testing between MDFs The proper use of the correct type of tools in making a termination, and the use of approved techniques for soldering, crimping and wire wrapping as defined in TI TGEN This is especially important when working on terminations that already carry working circuits The use of correctly colour coded jumper wire according to the circuit type to aid future identification. This is defined in TD CB 091 and TI TGEN The updating of local site records at the time that changes or additions are made, The subsequent updating of LL other records shall be initiated The regular inspection of cable terminations to ensure both their mechanical and electrical integrity. 3.2 Signalling and electrification supervisory circuits in telecommunication cables must be identifiable at all access points (for colours of jumper wire to be used see TD CB 091). Signalling and electrification supervisory circuits shall also be identified by RED markers fitted to the pair/conductor terminations. IDC type terminations shall have red marker plugs or caps fitted to the connector face. Where cables are terminated on 2B and 0B terminations as binding posts, red plastic dome nuts shall be fitted. For other types of termination, any red marker shall be used to suit the termination.

4 GT/EH H802 Date MR 94 B2 Withdrawn Document STNDRD FOR TELECOMMS WIRING ND TERMINTIONS 3.3 Whenever the need arises for the installation of jumpers for temporary circuits, they must always be installed to the same standard as those for a permanent circuit irrespective of the anticipated life span. 3.4 Copper cables must have all pairs terminated on a frame. Exceptionally, unterminated pairs may be tied back in the approved manner as detailed in TI TGEN 0073, but only on cables in which no signalling and electrification supervisory circuits are carried. Signalling and electrification supervisory circuits are not to be introduced to a cable with pairs tied back. 3.5 Spare fibres in optical cables may be terminated, OR coiled up in the termination housing. 4 PROCEDURES FOR WORKING ON TELECOMMUNICTION CBLES 4.1 Intrusive cable access (for example, for cable repairs) must only be commenced under an authorised possession arranged in accordance with TI TGEN This will ensure that: the potential disruption to traffic is advised to the user with sufficient notice, or that traffic is switched to alternatively routed paths and that safety critical traffic has been protected from causing operational difficulties by persons with specific and relevant responsibility (TD MTC 079 refers). Under certain circumstances, a conditional possession may be granted which will limit intentional work to an identifiable and accessible unit of the cable core (for example, a tube of fibres in a spliceless joint). 4.2 Work shall not commence on any optical cable until the associated transmitting light source(s) have been confirmed as disconnected. 4.3 The work shall be completed by satisfactory testing of the affected cable or cable unit: Insulation resistance tests must be carried out on all pairs to which traffic will be restored, or at least 50% of the pairs in the cable, whichever is the greater. On completion of insulation resistance tests, end-to-end DC loop resistance tests must be carried out before restoring traffic. It is permissible to then joint and test end-to-end DC loop resistance of the remaining pairs to enable early restoration of traffic. OTDR (Optical Time Domain Reflectometer) and insertion loss tests shall be completed on all affected fibres of optical cable. It is permissible to joint and test on a fibre-by-fibre basis to enable early restoration of traffic 4.4 Since telecommunication cables are employed for a wide variety of circuits in both telecommunication and signalling applications, the possibility that a Wrong Side Failure might be caused as a result of work being carried out has to be considered. TD MTC 079 defines other procedures to be adopted under safety related telecommunications failures.

5 STNDRD FOR TELECOMMS WIRING ND TERMINTIONS GT/EH H802 Date MR 94 B3 5 NUMBERING OF TELECOMMUNICTIONS MDF ND LINESIDE TERMINTIONS This section applies to LL NEW INSTLLTIONS of single and double sided MDFs. These procedures shall be adopted for terminations in new location cases and new enclosures in equipment rooms. 5.1 The verticals on a single sided MDF shall be labelled, B, C, etc from left to right. Double sided MDFs shall have verticals labelled F, BF, CF, etc and those opposite shall be labelled R, BR, CR, etc (designating front and rear). These may also correspond to line side and equipment side 5.2 Where additional verticals are added to the left of vertical, these shall be labelled Z, Y, X, or ZF, YF, XF, etc respectively from right to left. Verticals added on the opposite side to the right of vertical R shall be labelled ZR, YR, XR, etc. 5.3 In the case of double-sided frames within lineside cabinets, then for the purpose of determining the front and the rear of the cabinet, the front shall be the side facing the track (or facing in the up direction when mounted sideways). 5.4 Each termination strip or block shall be designated as a Level. Where insulation displacement terminations are used, a level is one 10 pair strip. Where other types of termination are used, each level is one individual termination block regardless of the number of cable pairs on that termination. The levels on all verticals shall be numbered 01, 02, 03, etc from top to bottom. ll levels shall have a designation regardless of whether or not there is a termination strip installed. 5.5 Cables shall always be terminated with pair 1 at the top regardless of whether the cable is routed to the termination point from above or below. Wherever possible cables shall be terminated with all pairs on the same vertical (ie, not split across more than one vertical), starting with vertical. 5.6 Each cable termination shall be clearly labelled. The minimum information required is the cable count (ie, 10 pair, 20 pair, etc) and cable identification as defined by TD GEN 111. Signalling circuits shall be marked as detailed in Part B: Section 4.2.

6 GT/EH H802 Date MR 94 B4 Withdrawn Document STNDRD FOR TELECOMMS WIRING ND TERMINTIONS PPENDIX DEFINITIONS IDC OTDR MDF Insulation Displacement Connector Optical Time Domain Reflectometer Main Distribution Frame PPENDIX B REFERENCES TD CB 091 TD GEN 111 TD MTC 079 TI TGEN 0046 TI TGEN 0073 Telecommunications Jumper Wire National Numbering Scheme for Telecomms Bearer Systems Management of Safety Related Telecommunications Failures Procedures for the Temporary Disconnection of Telecomms Services to Customers During Repairs Wiring & Termination Procedures

7 STNDRD FOR TELECOMMS WIRING ND TERMINTIONS GT/EH H802 Date MR 94 B5 PPENDIX C TYPICL LBELLING SCHEME ON VERTICLS VERT VERT B Labelling of levels using 10 pair insulation displacement strips (eg, Krone, DC) Labelling of levels using 100 pair termination block (eg, Portablock) END