Railway Control Cable Termination Frame & Temporary Cable Termination Frame (CCTF & TCTF)
Control Cable Termination Frame
* The control cable termination frames (CCTFs) are wall mounted lockable cabinets. They are used to interface the internal wiring of the Signalling Equipment Room(SER) with external cabling to the wayside equipment via miniature circuit breakers (MCB’s) / terminal links.
* The internal wiring enters the top of the CCTF cabinet whilst the external cables enter the bottom of the CCTF enclosure.
* Generally internal wiring will be terminated on Left side of MCB and external wiring will be terminated on right terminal of MCB.
* The CCTF dimensions are 300mm deep by 1000mm wide by 1400mm high. The CCTF is an enclosed type with access from the front via a double door arrangement.
* They are delivered to site fitted with four vertical 1000mm long DIN rails labelled A,B, C and D.
* There is a 42-way earth bar mounted horizontally at the bottom of the enclosure below the DIN for the termination of the screens / drain wires of cables.
* For each vertical din rail of 1000mm, MCB/terminal combination of 1) 42 MCBs with 30 terminals (see Fig. 1) or 2) 56 MCBs (see Fig. 2) would be used.The numbering of MCBs / Terminals is as shown in fig. 1 and fig. 2.
* The numbering is from top to bottom and will include the letter (i.e ‘A’, ‘B’, ‘C’ or‘D’) of the DIN rail to uniquely identify it.
* According to the requirement the plate racks are mounted on the Din rails.
* As per LUL spec. TLL-ENG-S7266-A1 (E7204 A3) Para 9.24.5. a maximum of 2 wires shall be connected to any one terminal.
* As per REN No.THL-MCML-REN -2009-02_rev.01, for avoiding more than 2 wires on MCBs (on certain circuits with earthed Nx supply) feed through links are used duly replacing the MCBs.
* A minimum of 10% spare terminals shall be provided on each terminal block on the rack. Terminals used to terminate spare multi core wires should not be considered as spare terminals as per TLL-ENG-S7266-A1 (E7204 A3) Para 9.24.6.
* Cable cores, whether main cables, tail, or multi cores shall be terminated. It is not permitted cut-back spare cores in SERs containing safety wiring as per TLL-ENG-S7266-A1 (E7204 A3) Para 9.34.6.
* Cables, except any main power supply cables, entering and leaving SER’s,signal apparatus boxes and lineside kiosks shall be terminated on racks in order of their core numbers on combined terminal/fuses or terminal/links as per TLL-ENG-S7266-A1 (E7204 A3) Para 9.34.7
CCTF / TCTF
* Where non vital functions are to be employed within the CCTF that accommodates the vital interface circuits, all non vital circuits will be terminated using a separate row within the CCTF and shall be facilitated by separate cabling.
* As an exception that RS & RGI are permitted in the same cable.
* A dedicated CCTF will house all the MCBs and terminals associated with circuits having Earthed NX supply.
* All SPARE and NOT USED MCBs to be locked off using ABB padlock and Adapter kit P/N GJ F110 1903 R0003.
* The TCTF’s are similar to CCTF. Only MCBs are provided on DIN rails (See Fig.2). They are used to interface signalling circuits for the ‘Cut-In’ design between the new TBTC SER and the existing WRSL SER or existing Interlocking Machine Room (IMR) or existing Relay Room (R/R) via MCBs.
* 10% spare is not applicable for MCBs since TCTF is used for temporary phase /stage working.
CCTF/TCTF Screen Earth Bar
* CCTF / TCTF is provided with 42 way Screen Earth Bar having holes fitted with suitable steel studs for terminating the cable screens / drain wires.
* In certain cases the screens of the cables are kept insulated from the SEB, by replacing the steel stud with nylon studs at the time of COC commissioning, for reducing the effect of Capacitive coupling in screened concentric cables. However these nylon studs are again replaced by steel studs at the TBTC commissioning.
* The Screen Earth Bar is insulated from the frame and positioned below the DIN rails and on the front, between cable entry point and the door.
* The earth connection to the Screen Earth Bar is from the signalling bar of the room where CCTF/TCTF is installed.
CCTF/TCTF Screen Earth Bar Allocation
* Normally the following screen earth bar terminals are allocated for cable screens / drain wires :
* Cables on Row A – should use Screen Earth Bar terminal numbers 2-11
* Cables on Row B – should use Screen Earth Bar terminal numbers 12-21
* Cables on Row C – should use Screen Earth Bar terminal numbers 22-31
* Cables on Row D – should use Screen Earth Bar terminal numbers 32-41
* Screen Earth Bar (CCTF/TCTF) terminal 1 is used to terminate the earth cable from the SER Signalling Earth Bar.
* Screen Earth Bar terminal 42 is used to terminate the earth cable from CCTF or TCTF cabinet earth stud.
CCTF/TCTF Screen Earth Bar Allocation, CCTF/TCTF Screen Earth Bar, CCTF / TCTF, Control Cable Termination Frame & Temporary Cable Termination Frame (CCTF & TCTF)