29-April-2022 || By: Admin
If
Not planning for the future
When you’re determining your cable count for today’s needs, you ought to also calculate what your
future demands are going to be . Communication and electrical pathways are stable components and
have life expectancies far greater than that of the cabling system they contain. And as systems
still converge and expand with new emerging applications, the quantity of cables you’ll need is for
certain to grow. It is more time- and cost-efficient to put in a bigger cable tray now then to
upgrade your network infrastructure later.
Not supporting the cable tray correctly
The failure to properly install a cable tray may result in safety implications starting from a
failure to properly secure the cables to a complete collapse of the trays. VE2 may be a National
Electrical Manufacturers Association (NEMA) standard that outlines cable tray installation
practices. Section 3: “Installation” describes the various sorts of supports also as details on the
way to install them. Key areas like where to locate supports for straight sections and fittings also
as where to locate splice joints also are covered. In VE2, the quality provides charts that
calculate how often expansion joints are required and the way to properly set the gap for expansion
connectors also as locations for hold down clamps and expansion guides.
Improper choice of cable tray
There are many various sorts of cable trays available, from ladder to ventilated trough to wire
basket to solid bottom. Knowing the sort of cable and therefore the environment during which it'll
be installed will determine the selection of cable tray you would like . For example, single
conductor cables must be installed during a ladder or ventilated trough. Solid bottom trays would
only normally be specified where EMI/RFI shielding protection may be a concern. Low voltage telecom
cables, control and AV cables are traditionally placed in wire basket cable trays. Weight capacity
and cable volume of the tray must be calculated so as to specify the right tray criteria. Trays
requiring greater span distances would require a greater cross sectional area for the side rails.
It’s vital that you simply fully understand all aspects of your installation so as to understand
which cable tray will do the simplest job.
Incorrect grounding and bonding
Aluminum and steel cable tray systems are excellent equipment grounding conductors as long as
they're properly designed, installed and inspected. These sorts of cable trays are permitted to be
used as an equipment ground conductor (EGC), per NEC 392, when labeled intrinsically also as marked
with the available cross sectional area. If the cable tray is to be used as an EGC, bonding jumpers
must be placed on both side rails at each tray joint, unless the splice plates meet the electrical
continuity requirements of NEMA VE1. If the tray connections are UL Classified, bonding jumpers or
continuous ground components aren't required. It is important that the grounding of cable tray
systems, including the cables within the tray, is inspected before the cabling within the tray is
energized and before cable is installed. This will help to eliminate any dangerous situation which
will occur thanks to improper bonding.
Calculate a proper fill ratio for the cable tray you are using
Overfilling a cable tray can cause poor cable performance, damage and will become a security hazard.
NEC 392.20-22 outlines the wants for installing cables within cable trays by taking the dimensions ,
voltage and numbers of conductors under consideration so as to develop the right fill ratio of
cables in reference to the tray’s cross sectional area. Where low voltage communication cables are
used typically either a 40 or 50% rule is in effect. For electrical cables it becomes far more
stringent thanks to questions of safety related to higher voltages. Typically, the sum of the
diameters of all single conductor cables shall not exceed the cable tray width, and therefore the
cables shall be installed during a single layer.
Hutaib Electricals is a