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TECHNICAL INFORMATION
Technical information
284 |
PVC-U perimeter trunking systems
Material
PVC-U is flame retardant and self-
extinguishing. It provides a 100%
recyclable material with good
sustainability.
Installation
Positioning
When used as a skirting system,
sufficient clearance should be allowed
between the floor covering and
the profile fittings that clip over the
cover i.e. 5mm + floor covering is
recommended.
Expansion/contraction
PVC-U expands and contracts at a
uniform rate of approx 5.25mm in
a 3 metre length for a temperature
change of 25°C. Therefore, a 3mm gap
between each length of trunking base
is recommended.
Adequate allowance is made within
the fittings for thermal movement
of the covers, which have a 10mm
overlap on each side.
Fitting
• The base is supplied with pre-cut
elongated holes at 250mm centres.
• Internal couplers on base units are
not required.
• To fasten base, use No 8 round head
screws and washers.
• Avoid over-tightening to permit
thermal movement.
• The use of plastic caps over screw
heads is recommended to protect
installed cables.
• To cut the trunking, use a fine-
toothed panel or power jig-saw.
• External moulded fittings overlap
the joints by up to 10mm to cover
cutting inaccuracies.
• A variable angle jig-saw or chop
saw is recommended for cutting 45°
mitres.
Single lengths
Where it is required to fit a single
length of trunking (under 3 metres)
between two inside walls and no
accessory box is fitted, it is advisable to
install a coupler in the centre of the run
to facilitate the removal of the cover.
Joints and bends
• Base joints should have a 3mm gap
to allow for expansion.
• External bends: base should be cut
square.
• Internal bends and flat angles, the
base must be mitred 45° to ensure
total enclosure of trunking, including
any internal fitted segregator.
• Tees and crossovers are available
prefabricated.
• External moulded fittings overlap the
joints by up to 7mm to cover cutting
inaccuracies.
Bend radius control
The bend radius control fittings for
Twin Plus provide a bend radius of
50mm
Accessory boxes
If the accessory box is to be mounted
in the alternative compartment to the
supply, drill the main web adjacent
to the box position. Remove the
appropriate knock out and clip the box
into the trunking base. For boxes in
the same compartment as the supply,
remove the appropriate box knock-
outs and clip the box into trunking
base. When boxes are installed
consecutively, a 14mm wide spacer
(ES1) is required to cover the space
between the boxes.
• Part M box assemblies with
contrasting coloured faceplates are
available to meet the requirements
of DDA regulations for Visual
Impairment.
Covers
The covers have been designed to
remain in position irrespective of
impact during normal conditions,
minor undulations of the mounting
surface, and to limit unauthorised
removal.
Covers – fitting
Covers are clipped into place from the
front. If accessory boxes are installed,
the covers are butt-joined to the edge
of the box. For the fitting of couplers to
conceal the cover joint, a gap of 30mm
is left between the two cover ends.
Covers – removal
To remove a cover, first detach a
coupler, internal or external bend
component to gain access. Both covers
can then be gently eased off the base.
Screening
Special conductive spray coating can
be applied to one compartment, the
cover, accessory boxes and fittings,
to screen data cables against EMI
interference.
•
For data/voice circuits only:
Warning: Owing to its relatively
high surface resistance, CS coating
SHOULD NOT be in contact with low
voltage circuits BS7671 (1992) 50
V.A.C. – 1000 V.A.C. unless additional
measures are undertaken.
Antimicrobial
For technical details of antimicrobial
Twin Plus Bio trunking, please refer to
Laboratory and Healthcare section.
Method of continuation through
a partition wall
Continue the main lateral run of base
through the partition wall with short
lengths of cover fitted where the
trunking passes through the partition.
The partition wall trunking is then
butted up to the main run and the joint
covered by an Internal bend.
Offset dimensions
The minimum set that can be
accommodated in the same plane
(from internal to external bend), is
shown below.
169mm
268mm
169mm
STERLING TWIN PLUS DATA BENDS
STERLING TWIN PLUS STANDARD BENDS
3mm
3mm
3mm
Twin Plus trunking
Large data capacity bend
Standard bend
MIN
90mm
5mm +
FLOOR
COVERING
STERLING COMPACT
AND PROFILE