Installation of gi cable trays and trunking in the roof area.
Cable tray and trunking installation.
All the accessories shall be factory made.
Installation method of trunking.
It is used to make cable laying and good support.
Install 12 5mmx1 5mm copper earth bonding straps externally between all length of cable tray trunking cable ladder and provide a copper bending straps across each joint.
All fittings are available in sizes and types.
Fittings fittings are sections of cable trays which are joined to other cable trays sections for the purpose of changing the direction elevation or width of the cable run.
All metallic cable trays shall be grounded as required in article 250 96 regardless of whether or not the cable tray is being used as an equipment grounding conductor egc.
Trough ventilated cable tray.
Fixed with independent mushroom headed electro plated bolts nuts and serrated washers.
Pedestal shall be provided for the floor mounted supports for the cable trays and trunking.
Solid bottom cable tray.
Make expansion connections wherever cable tray and trunking are crossing building expansion joints.
Cable tray cable ladder cable trunking all of these are available with a full range of fittings and accessories.
Types of cable trays.
Where sizes of cable trays have not details on drawing then tray shall be appropriately sized to support the cables without bunching and a 25 reserve margin shall be permitted in size and weight to be loaded.
Cable tray and or trunking shall be kept on worksite project undercover in dry well ventilated storage facilities building.
The egc is the most important conductor in an electrical system as its function is electrical safety.
This cable tray support system drawing has isometric view and cross sectional view.
For adequate space for cable installation and maintenance sufficient space shall be provided and maintained above cable tray ladder and trunking.
Cable trays are to be made good at all.
Sharp edges or other things in cable tray trunking and ladder that are capable of damaging the insulation or cable sheaths should be avoided.
Below drawing shows how to install cable tray and its support system.
Tray and trunking joints are to be positioned as close to the supports as possible.
Install cable tray support using a pre fabricated flange or gi channel.
Following are the steps to be done for laying cables on wall mounted cable tray.
The metal in cable trays may be used as the egc as per the limitations of table 392 60 a.
Metallic or pvc trunking shall be fixed by means of suitable screws to approved type of asbestos or fibre fixing plugs at intervals not exceeding 60.
The size length and intervals of the support to be as per the specification standards.
Cable tray sizes cable tray types ladder and perforated cable tray are the two types of electrical trays.
