NFPA 70 –
The National Electrical Code
covers the installation requirements for the safe application of cable tray systems including ladder, ventilated trough, ventilated channel, solid bottom and other similar structures.
What article in the NEC covers cable trays?
The article covering cable trays and their installation requirements has been moved from Article 318 in the 1999 NEC to new
Article 392
in the 2002 NEC. Cable trays are not limited to industrial facilities and can be installed in commercial and residential facilities.
Are cable tray covers required?
For outdoor installations, the most desirable cable tray system is a ladder cable tray or a ventilated trough cable tray
without covers
. If covers are used they should be the ventilated type. Cable tray wiring systems have a 30-year plus proven track record of safety and dependability.
Which of the following is an NEC requirement for grounding and bonding cable trays?
As per NEC Section 318-7(a), all metal cable trays must be grounded as required by
NEC Article 250
regardless of whether or not the cable tray is being used as an EGC. 2.
How do you install a cable floor tray?
- Make sure you have adequate clearance under the raised floor to lift and secure the cable tray system at the height desired. …
- Remove the appropriate crossmembers of the raised floor to insert the cable tray, if necessary.
What types of cable can be installed in cable tray system?
Although less commonly used, several other types of cables are permitted to be installed in cable trays. These include:
Type AC, CATV, NM, NMC, NMS, SE, USE and UF
.
Is code for cable tray installation?
IEC-61537
– This international standard specifies requirements and tests for cable tray systems (such as; all metal cable trays including wire mesh cable tray and nonmetallic cable trays) for the support, accommodation of cables and possibly other electrical equipment in electrical and/or communications systems …
Why are cable tray covers used?
Without covers, it
allows maximum free flow of air across the cables
. This allows the heat produced in the cable’s conductors to effectively dissipate. The rungs of the ladder cable tray provide convenient anchors for tying down the cables in the non-horizontal cable tray runs.
Why cable trays should be installed and maintained properly?
Cable trays can
provide a safe structure for a wiring distribution system
. If not designed or installed properly, wiring inside cable trays may pose hazards such as fire, electric shock and sudden blast events. … Proper grounding must be done before cables are installed and tested before cables are energized.
What is the importance of proper bonding and grounding in installing cable trays?
Correct bonding practices
In addition to
providing an electrical connection between the cable tray sections and the EGC
, the grounding clamp mechanically anchors the EGC to the cable tray so that under fault current conditions the magnetic forces do not throw the EGC out of the cable tray.
Does cable ladder need to be earthed?
Ladders manufactured from steel or aluminium are conductive, and hence for
safety can often require appropriate grounding to meet personnel safety regulations
. Indeed this is a safety requirement on a lot of large electrical installation projects, particularly when dealing with high voltage cables.
What is cable tray installation?
According to the National Electrical Code standard of the United States, a cable tray is
a unit or assembly of units or sections and associated fittings forming a rigid structural system used to securely fasten or support cables and raceways
.
Does conduit need to be bonded to cable tray?
A separate EGC is commonly selected when single conductor cables are used. Either alternative can be used for non-metallic cable trays. These alternatives provide a two-point connection from the power source to the load, however, any conduit, cable tray, or raceway
must still be bonded back to the power source
.
How do they install cable?
- Connect the cable from the wall to the cable box input, then screw the coaxial cable onto the cable box’s output connector.
- Screw the other end of the cable into the TV’s cable input connector on the back (most current TVs still have them).
What are the rules for installation clearances for the telecommunication cables in cable trays?
Clearance requirements for cable tray accessibility: a.
Maintain a clearance of 6” between top of cable tray and ceiling structure or other equipment or raceway
. b. Maintain a clearance of 8” between at least one side of cable tray and nearby objects.
What is the most important thing when doing installation of cable tray?
The important considerations for cable trays are
their resistance to fire, the potential for ignition and propagation of cable fire between adjacent trays
. This is related to the cable materials, the layout of the cable trays, the fire protection system, and the area ventilation system.
What are the 5 basic cable tray types?
- Aluminium Cable Trays. Cable trays manufactured with aluminium by cable tray manufacturers in India are known as aluminium cable trays. …
- Steel Cable Trays. …
- Stainless Steel Cable Trays. …
- Ladder Type Cable Trays. …
- Solid Bottom Cable Trays.
How do you make a cable tray?
Area of Cable Tray =
Width of Cable Tray X Height
of Cable Tray. Area of Cable Tray =300X100 = 30000 Sq.mm. Checking Width of Cable Tray. Calculated Width of Cable Tray as per Calculation=No of Layer of Cable X No of Cable Tray Run X Width of Cables.
Where can cable tray be installed?
Cable trays shall be permitted to extend transversely through partitions and walls or
vertically through platforms and floors in wet or dry locations
where the installations, complete with installed cables, are made in accordance with the requirements of 300.21.
How do you install a cable tray on the wall?
- Install cable tray support using a pre-fabricated flange or GI channel. …
- Fix the cable tray as shown on the drawing.
- Lay the cable keeping the distance as per calculation.
- Tie the cable using cable tie and label the cables as required.
What is basket tray used for?
Wire Cable Tray / Basket: These have a wire basket-like frame that supports and suspends cables and wiring. This open design
prevents heat and dust build up
, as it has less surface area to accumulate and settle on.
What is a tray ceiling?
A tray ceiling (also sometimes called a trey or recessed ceiling)
resembles a large upside-down tray that is set into the ceiling of a room
. Generally, the center part of the design is between 6 and 14 inches higher than the perimeter.
What is Ladder cable tray?
Ladder trays are
prefabricated metal structures
that consist of two side rails connected by individual transverse members or rungs. Ladder tray is the most common and the most economical type of tray, also providing maximum ventilation for cabling.
What is bonding jumper in electrical?
A bonding jumper is
a reliable conductor to ensure the required electrical conductivity between metal raceways required to be electrically connected
.
What is a equipment grounding conductor?
Equipment Grounding Conductor (EGC) –
A conductive path that is part of an effective ground-fault current path and connects normally non-current-carrying metal parts of equipment together
and to the system grounded conductor (service neutral conductor) or to the grounding electrode conductor, or both.
What stops cable from spilling off the ladder rack runway?
Cable Retaining Post for 1.5 in. Wide Cable Runway, Straight and 90-Degree – Hardware Included
. Increases the volume of cabling running through your cable ladder system and prevents it from spilling over the sides of the runway.
What type of tray consists of two parallel channels connected by rungs?
Ladder-type cable tray
consists of two longitudinal side rails connected by individual cross members or rungs.
Is cable tray mechanical protection?
Cable ladder systems and cable tray systems are designed for use as supports for cables and not as
enclosures giving full mechanical protection
. They are not intended to be used as ladders, walk ways or support for people as this can cause personal injury and also damage the system and any installed cables.
Is cable tray extraneous?
c) The tray/ladder is
neither an exposed/ extraneous-conductive-part
then it WON’T require earthing or bonding. This is a conductive part of equipment which can be touched and isn’t normally live, though it may become live under fault conditions.
What is conduit bonding?
What Are Conduit Bonds? Conduit bonds are
municipal securities designed to raise capital for revenue-generating projects that benefit the public
. For example, a for-profit real estate development firm may issue conduit bonds to finance the construction of student housing or low-income housing projects.
What is a conduit sleeve?
Carlon® Conduit Sleeve Couplings are specifically
designed for pass-through applications in concrete construction
. … They eliminate the need for duct tape, clamps and special mounting means while providing superior aesthetics by blending into the concrete. Applications – Concrete walls, columns and posts.
What is Channel cable tray?
Channel cable tray is a
sort of fully enclosed cable tray made from stainless steel, carbon steel, FRP, aluminum alloy
. Channel cable trays have powder coated, hot-galvanized and electro galvanized surface mainly used to support computer cables, communication cables, thermocouple cables and other control cables.
