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Supporting cable trunking systems
The connector between all types of cable trunking lengths is to provide
electrical and mechanical connection between the lengths ; it does not
provide a load bearing connection between lengths. Consequently each
length must be fully secured to the wall so that there is no significant
bending force applied to the connector
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Electromagnetic compatibility (EMC)
Cable trunking and duct systems are considered passive under normal
conditions in respect of electromagnetic influences. The installation of
current carrying cables may cause emissions and these cables may
also be influenced by electromagnetic signals from elsewhere, but the
degree of influence will depend on the nature of the installation and
the apparatus connected to the system. Specific information relating
to the details of cable separation required according to the type of
signal, and further information on the subject of EMC, is provided in the
relevant Standards and Regulations. However, as a basic principle, if
power and data cables are run in separate compartments of a metal
trunking system, then the metal segregation will significantly reduce the
possibility of one circuit having an undesirable effect upon another
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Installation
110, 130, 170 and 170A systems are all suitable for dado applications
170 and 170A systems are also suitable for skirting applications
Ensure clearance between trunking body and floor finish is allowed to fit
the cover straps etc
The system is designed to fit together without the use of screws on the
body, lid or component parts, with the exception of the wiring accessory
back box which has a screw to secure a sliding plate into the body
Trunking body
The trunking body has fixing points every 500 mm and 250 mm from
each end
It is recommended to secure at least every metre and near to
joints / ends
Use washers and dome head screws or plastic caps to avoid damage to
cables
Do not over tighten
Fit trunking body to wall ensuring it is level with preceding length and
that joints are closely butted together
Once secured, install earthing coupler to trunking joint by simply
pushing into place ensuring that the coupler is evenly distributed over
both parts
For best results when cutting, use a fine tooth circular saw
Cut edges must be de-burred to avoid cable damage
The trunking body is supplied with a protective film to avoid marks and
scratches during installation ; this can be removed when lids are fitted
Fittings
Fittings (e.g. bends, tees) are installed in the same manner as the
trunking body
Dividers
The trunking can be divided into two or three compartments
Dividers are supplied in 1 m lengths and have rolled edges for safety
The multifunction snapper clips into the base and provides two locations
to fit the dividers
The snapper is earthed to the trunking body and dividers automatically
when installed
One snapper is required per metre
Additional snapper clips may be required at the end of the run and
closer to back boxes. The snapper also provides additional support to
the lid
A base divider is also available to further separate the base
compartment if required
Back boxes
The 35 mm steel back boxes are slotted into place and secured by
sliding the two fixing brackets under the return and tightening the screws
Boxes are designed to have some lateral movement for final adjustments
Marks in the rear of the trunking body every 100 mm allow for easy
positioning
20 mm knockouts are provided on all sides and the base. Once
removed, 20 mm grommets should be fitted to protect the cable from the
cut edge before feeding cable into box
Lids
Once the wiring installation is complete, lids are simply clicked into
place
Earthing cams are located every 150 mm
Minimum length of lid should be 50 mm and include at least one earthing
cam
To remove, the lids should be carefully lifted from one end
This can be from any joint, fitting or wiring accessory location
If the installation comprises a single length between two walls, a coupler
joint is required in the centre to aid lid removal
25 mm wide cover straps are available to provide a neat finish at lid and
body joints
These clip into place over the completed trunking run after the lids have
been fitted
A wider (40 mm) tolerance cover strap is also available
Earthing
The Legrand steel perimeter trunking system is designed with parts
that provide earth continuity when installed, however, the connection to
earth is the responsibility of the installer. Legrand provides the means
to achieve a correct and safe installation. It is the responsibility of the
installer to determine the number and position of earth connections
steel perimeter trunking
technical information
