L
OOP
D
ETECTOR
H
ANDBOOK
667/HE/20663/000
Issue 13
Page 18
Backfilling shall be with fine cold asphalt rammed into the slot and finished
with a surface layer of hotpour of 20 mm nominal depth.
2.9
Joint Loop Tails to Feeder Cables
STC approved joint is the acrylic joint to specification 915/4/03118/etc. These
joints can be used in underground chambers, soil and encapsulated in slots in
carriageways. When customers specify heat shrink joints, joints to
specification 667/4/15084/etc. will be used. These joints are only suitable for
encapsulation in slots in carriageways.
Where joints are installed in the road surface, the joint is to be made within
one metre of the loop, or the nearest loop to the feeder cable where a series
of loops are joined together by tails. Slot widths for the various joints are as
follows:
915/4/03118/000
40 mm
915/4/031188001
55 mm
When using heat shrink joints 667/4/15084/etc feeder slots to be widened by
10mm for insertion of joint.
Guidance for loop to feeder joint connections as follows:
915/4/03118/000 - Use with 3 pr and 4 pr cables, maximum loop conductor 8
915/4/03118/001 - Use with 3 pr and 4 pr cables, maximum loop conductor 12
667/4/15084/000 - 1, 2 or 3 loops to a 1 pair cable
667/4/15084/001 - 2 or 3 loops to a 1 pair cable, 2 loops to a 2 pair cable
667/4/15084/002 - 2 or 3 loops to a 1 pair cable, 3 loops to a 3 pair cable
667/4/15084/003 - 2 or 3 loops to a 1 pair cable, 4 loops to a 4 pair cable
The depth of slots for joints must be such that their cover of epoxy/asphalt/hot
pour is not less than 65 mm. Prior to commencing backfill, the joint shall be
laid evenly on the floor of the slot then covered with epoxy resin, and if
possible left for 30 minutes before commencing the next operation. Following
the application of epoxy resin, fine cold asphalt should be rammed into the
slot built up to approximately 10 mm below road level. Following this, the fine
cold asphalt must be covered with hot bitumen and allowed to cool.
2.10 Cable Entry Through and Under the Kerb
The feeder cable or, where permitted, short lengths of loop tails as described
in section 2.6.1, shall be through a duct laid through or under the kerb as
shown in Figure 28 and Figure 29. The concrete or cold asphalt shall be
compacted into a smooth bed between the floor of the slot and the duct. The
cable(s) shall be laid on this bed before backfilling to the road surface.