RAILWAY TRACK SIDE DISCONNECTION BOX & COMBINED CABLE TERMINATION BOX

RAILWAY TRACK SIDE DISCONNECTION BOX & COMBINED CABLE TERMINATION BOX: DBOX/CCTB will be used as a cable interconnecting facility between the SER and wayside equipment. DBOX/CCTB will also be used where the cable requirement exceeds the maximum length of the cable available. Cables requiring connections to the line side equipment or are to be routed across the track, or connected to the track shall be made via a termination box sited adjacent to the cable run or via an environmentally sealed and mechanically key connected as per TLL-ENG-S7266-A1 (E7204 A3) para 9.34.2.

Joints in cables between terminations shall be kept to a minimum stop. Any joints shall be by means of an approved LUL jointing method. However, there shall be no joints or splices in safety multicore cables during installations.

Where no under track crossing/over track crossing cable routes (UTX/OTX) are available and the cable has to cross the track, DBOXes / CCTBs shall be provided on either side of the track and uses Track crossing cable assembly (plug coupled cable).

The DBOX/CCTB will be fitted adjacent to the railway track, in either an outside location or in a tunnel and may be mounted on the cable route, on an individual post or wall. To the possible extend, DBOX /CCTBs should be avoided in the platform inverts, as there is a possible risk to the maintainers during maintenance/faultfinding.

The Disconnect terminals of type WTL/6/1/STB and Feed through terminals of type WTD/6/1 are provided in DBOX / CCTBs. These terminal numbers are identified by Dekafix marking tags on both sides.

A minimum of 10% spare terminals shall be provided on each terminal block on the rack. Terminals used to terminate spare multicore wires should not be considered as spare terminals as per TLL-ENG-S7266-A1 (E7204 A3) Para 9.24.6.

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

The normal practice is to terminate the cable from SER side on the Left Hand Side of the terminals in the DBOX/CCTBs where the DIN rails are vertically mounted and on the Top Side of the terminals where the DIN rails are horizontally mounted.

There are different types of DBOX/CCTBs to meet the requirement depending upon the type of cable used, number of cable terminations, cable screen/drain wire terminations etc.

The Gland plates and cable glands for the cable entry to the DBOX/CCTB shall be as per the requirement(no. of cables).

The DBOX/CCTB shall be labelled as DBOX/CCTB with type, prefixed by the function it refers to. When there is only one box for the function, it shall be DBOX/CCTB and when the boxes are more than one, it shall be numbered starting from SER as DBOX/1,CCTB/1, DBOX/2 ,CCTB/2 etc.

Every DBOX/CCTB shall be earthed using a 16 sq mm cable code C34, connected to the nearest star plate.

Type of DBOXes:
Type 1A – 20 Way Terminal DBOX
Type 1B – 40 Way Terminal DBOX
Type 1C – 46 Way Terminal DBOX

Type 1D – 23 Way Terminal Intermediate DBOX
Type 1E – 46 Way Terminal Intermediate DBOX
Type 2 – 16 Way Terminal DBOX

Type 3 – 30 Way Terminal DBOX (Proposed for Northern Line and awaited specification)
Type 4 – 60 Way Terminal DBOX (Proposed for Northern Line and awaited specification)

Type of CCTBs:
Type A – 80 Way Terminal Box
Type B – 60 Way Terminal Box

Type 1A – 20 way Terminal Dbox:
The Dbox will be used to terminate concentric pair and multi core cables.

Type 1A Dbox measures 306(H) x 306(L) x150mm wide, accommodates a single vertical length of DIN Rail centrally positioned
inside the Dbox identified as column ‘A’, fitted with 16 Disconnection terminals and 4 feed-through terminals.

The disconnection terminals are numbered reading from the top of the terminal arrangements 1-16 and used for the termination of cable conductors.

The feed-through terminals shall be mounted at the bottom end of the DIN Rail immediately after the disconnect terminals and are marked ‘S1,S2, S3 and S4‘ for termination of screens/drain wires. In Design, the terminals are identified as A01-A16 and AS1-AS4

 

Type 1B – 40 Way Terminal Dbox:

Type 1B Dbox shall measure 382(H) x 458(L) x 150mm wide, to accommodate two vertical lengths of DIN Rail inside the Dbox, fitted with 40 terminal links.

The terminals shall be arranged in two columns ‘A’ & ‘B’ Each Column is fitted with 16 disconnect terminals and numbered from the top 1-16 used for termination of cable conductors and also fitted with 4 feed-through terminals mounted at the bottom end of column immediately after the disconnect terminals marked ‘S1, S2, S3 and S4’ for termination of screens/drain wires.In Design, the terminals are identified as A01-A16 and AS1-AS4 for Column ‘A’ and for Column ‘B’ , as B01-B16 and BS1-BS4.

 

Type 1C – 46 Way Terminal Dbox:

Type 1C Dbox shall measure 382(H) x 458(L) x 150mm wide, to accommodate two vertical lengths of DIN Rail inside the Dbox, fitted with 46 terminal links. The terminals shall be arranged in two columns ‘A’ & ‘B’ . Column ‘A’ is fitted with 22 disconnection terminals and numbered from the top 1-22 to terminate conductors and also fitted with 3 feed-through terminals mounted at the bottom end of column immediately after the disconnect terminals marked ‘D1, D2 and D3’ for termination of drain wires.

Column ‘B’ is fitted with 18 disconnect terminals numbered from the top 1-18 to terminate conductor and also fitted with 3 feed-through terminals mounted at the bottom end of column immediately after the disconnect terminals and marked ‘D1, D2, D3’ for termination of drain wires.

In Design, the terminals are identified as A01-A22 and AD1-AD3 for Column ‘A’ and for Column ‘B’ , as B01-B18 and BD1-BD3.

Type 1D – 23 Way Terminal Intermediate Dbox:

Type 1D is a Dbox similar toType 1A with addition of 3 feed through terminals, suitable as intermediate Dbox for 1X7pr. / 2X3pr. screened concentric cable(s). Type 1D Dbox is of the same size as of Type1A. In Design, the terminals are identified as A01-A16 and AS1-AS7.

Type 1E – 46 Way Terminal Intermediate Dbox:

Type 1E is a Dbox similar toType 1B with addition of 3 feed through terminals in each column, suitable as intermediate Dbox for 7pr. / 3pr. screened concentric cables.Type 1E Dbox is of the same size as of Type1E. In Design, the terminals are identified as A01-A16 and AS1-AS7 for Column ‘A’ and for Column ‘B’ , as B01-B16 and BS1-BS7.

Type 2 – 16 Way Terminal Dbox:

The Type 2 Dbox will be used to terminate a maximum of 12-core cable.

The Type 2 DB shall measure 260(H) x 260(L) x 150mm wide (depth); to accommodate a single horizontal length of DIN Rail centrally positioned inside the box, fitted with 14 disconnect terminals numbered from the left 1-14, to terminate conductors and 2 feed-through terminals marked as ‘D1’ and ‘D2’ for the termination of drain wires.

In Design, the terminals are identified as A01-A14 and AD1 & AD2.

CCTB:

Where the number of main /tail cables and its connections cannot be accommodated in Dboxes, the alternative is CCTB having the facility with more cable entries and connections. Normally CCTBs are used nearer to functions in points and train stops.

Type A CCTB- 80 way terminal box:

The approximate size of CCTB is 300mm(H) X 650mm(L) X 150mm(D) to accommodate 4 vertical length Din rails inside the Dbox, fitted with 80 terminal links.

The terminals shall be arranged in four columns ‘A’ , ‘B’, ‘C’ & ‘D’. Each Column is fitted with 16 disconnect terminals and numbered from the top 1-16 used for termination of cable conductors and also fitted with 4 feed-through terminals mounted at the bottom end of column immediately after the disconnect terminals marked ‘S1, S2, S3 and S4’ for termination of screens/drain wires.

In Design, the terminals are identified as A01-A16 and AS1-AS4 for Column ‘A’, for Column ‘B’ , as B01-B16 and BS1-BS4, for Column ‘C’ , as C01-C16 and CS1-CS4 and for Column ‘D’ , as D01-D16 and DS1-DS4.

Type B CCTB- 60 way terminal box:

The approximate size of CCTB is 300mm(H) X 650mm(L) X 150mm(D) to accommodate 2 vertical length Din rails and 2X10 way terminal blocks inside the Dbox.

The terminals shall be arranged in two columns ‘A’ & ‘B’, Each Column is fitted with 16 disconnect terminals and numbered from the top 1-16 used for termination of cable conductors and also fitted with 4 feed-through terminals mounted at the bottom end of column immediately after the disconnect terminals marked ‘S1, S2, S3 and S4’ for termination of screens/drain wires.

Rows ‘C’ & ‘D’ are fitted with 10 way terminal blocks , for terminating cable snakes/ preformed cables.

In Design, the terminals are identified as A01-A16 and AS1-AS4 for Column ‘A’, for Column ‘B’ , as B01-B16 and BS1-BS4, for Column ‘C’ and ‘D’ as 1-1.1 to 5-5.5