Choosing Cable Tray for Structured Data Cabling
What makes cable tray for data cabling different from power containment
Selecting cable tray for data cabling is a different exercise from selecting it for power, and the difference is not obvious from a product catalogue. Both routes carry cables. Both need support. Both are sized by cross-sectional area. On paper they look like the same decision made twice.
They are not. A power cable is largely indifferent to how it is handled during installation. Its performance is set by conductor size, insulation and the derating applied for grouping and ambient temperature. A structured cabling link is different: its performance is determined as much by installation practice as by the cable itself. A twisted pair link that was kinked, crushed or bent too tightly will still connect, still carry traffic, and still fail a certification test.
Containment is where a large share of that damage happens. Which makes the tray a transmission performance decision, not just a mechanical one.
Bend radius is the constraint that decides the route
Every data cable has a minimum bend radius below which its geometry is permanently altered. Exceed it once during a pull and the link may never certify, with no visible damage to show for it.
Containment creates bend radius problems in two places. The first is at direction changes. The second is where cable leaves the tray to drop into a cabinet or an outlet position.
Wire mesh tray has a genuine advantage at drop-out points, because cable can leave the run at any position rather than only where a knockout was specified. But it is worth being honest about the direction changes, because this is where field forming and data cabling pull against each other.
A bend formed on site by cutting and folding a mesh section produces a tight transition. That is acceptable for power and often unacceptable for data, because the cable follows the containment. Where data links change direction, either the transition should be formed to a radius that respects the cable specification, or a manufactured component such as an inside bend should be used.
This is one of the few places where the faster installation method is not the right one. On a data route, the bend is worth slowing down for.
Separation between power and data
Running power and data in the same containment is common, sometimes unavoidable, and governed by rules that vary by country.
Two mechanisms are generally accepted. Physical separation by distance, where the required distance depends on the power circuit, the cable screening and the length of the parallel run. Or separation by barrier, where a divider or a separate tray carries one of the services.
ISO/IEC 11801-1 sets out the general requirements for generic cabling in customer premises, and the separation figures that apply to a specific installation come from that framework together with national wiring rules. What is worth noting at the containment stage is that separation is a sizing decision. If power and data share a route, the tray has to be wide enough to hold them apart, and that width has to be in the specification before the order is placed rather than discovered during the pull.
The failure mode here is predictable. A tray sized on total cross-sectional area alone is technically large enough and practically too small, because the area it offers cannot be used as a single pool.
Screening, earthing and what a tray does not do
An open mesh tray does not screen anything. It is not a Faraday cage, it does not form a continuous enclosure, and it should not be presented as electromagnetic protection.
Where interference is a concern, the mechanisms that work are the ones built into the cabling system: screened cable with a correctly terminated screen, adequate separation from the interference source, and correct earthing and bonding of the screening system. The containment supports those measures. It does not replace them.
Containment does have an electrical role in many installations, as part of the equipotential bonding arrangement. Where that is the case, joint continuity becomes an electrical specification rather than a convenience, and the requirement is set by national wiring rules rather than by the tray manufacturer. If the containment is intended to serve this function, it belongs in the specification explicitly, because it changes which jointing method is acceptable.
Running power and data on the same route? Send us the cable schedule and separation requirement and we will size the containment so both fit properly.
Bundle depth and what happens at the bottom of a stack
Twisted pair cable is not designed to be compressed. Deform the jacket and the pair geometry inside changes, and with it the impedance and the crosstalk behaviour of the link.
In a deep tray, the cables at the bottom carry the weight of everything above them. In a wide tray with a low side rail, cables sit largely in a single layer and that problem does not arise.
This is the main reason data routes are usually specified wide and shallow rather than narrow and deep, even though the narrow option offers the same cross-sectional area for less money. The area is equivalent; the mechanical condition of the cable at the bottom of the bundle is not.
There is a thermal argument alongside it. Cables in the middle of a dense bundle run warmer, and for cabling carrying power over Ethernet the heat rise across a bundle is a real design factor. An open structure with a single cable layer and air movement around it is the better condition on both counts.
Cross-sectional capacity published by width and side rail height makes this comparison straightforward. A 300 mm tray with a 60 mm side rail offers around 14,050 mm², and the same area achieved through a taller, narrower profile is not equivalent for data.
Moves, additions and changes
Data cabling changes more often than power. Cabinets are added, links are retired, floors are reconfigured for new occupants. The containment lives with that for its entire service life.
An open system allows a cable to be laid into an existing run rather than pulled through it, and allows a redundant link to be removed rather than abandoned in place. Over a decade of moves and changes this makes a substantial difference to how congested a route becomes, because abandoned cable is one of the most common reasons a containment route fills up.
Sizing for this is covered in more detail in our article on sizing a scalable cable management system, and the reasoning applies with particular force to data routes.
Where conduit or trunking is still the better answer
Open containment is not the right choice everywhere, and on a data route there are several cases where it is not.
- Exposed public or accessible areas. Where cable is within reach, closed trunking provides physical and security protection that open tray does not.
- Runs requiring screened containment. Where the EMI environment demands an enclosure as part of the mitigation strategy, a mesh tray does not deliver it.
- Compartment penetrations. Fire-stopping and compartmentation requirements at wall and floor penetrations are usually easier to satisfy with a closed system.
- Short final drops to outlets. Conduit or trunking is normally faster and neater than containment for the last few metres to an outlet position.
Most buildings use a combination. Open tray for the main distribution routes where capacity, access and airflow matter most, closed systems where protection, containment or aesthetics govern.
A representative cabinet room layout
The scenario below is illustrative rather than drawn from a specific project.
A commercial building has a floor distributor serving 240 outlet positions, with copper links routed above a suspended ceiling to four cabinets. The containment is specified on total cross-sectional area, using a 200 mm tray with a 100 mm side rail to fit the available void depth.
The area calculation is correct. Two problems appear during installation. The bundle over the last twenty metres approaching the cabinets is around four cables deep, which means the bottom layer is carrying the weight of the rest of the run. And the small power circuits sharing the route have to be lifted into a separate containment that was not in the original scope, because there is no width available to separate them.
Specified as a 300 mm tray with a 60 mm side rail, the same cross-sectional area would have been delivered in a broadly single layer with room to hold the power circuits apart. The material cost difference is small. The certification risk and the additional containment were not.
The same considerations scale up in data centre environments, where cable density is far higher and the containment above the cabinets is rarely finalised before installation begins.
Frequently asked questions
Is cable tray for data cabling better open or closed?
Open containment is generally preferred for main distribution routes because it supports single-layer cable placement, allows cable to be added without pulling through, and permits air movement around the bundle. Closed systems remain appropriate where physical protection, screening or fire compartmentation requirements govern.
Can power and data share the same tray?
In many installations yes, provided the separation required by the applicable wiring rules is maintained by distance or by a barrier. The practical consequence is that the tray must be sized for both services plus the separation between them, not for their combined cross-sectional area alone.
Does a wire mesh tray provide EMI shielding?
No. An open mesh structure does not form a continuous enclosure. Interference is addressed through screened cable with correctly terminated screens, separation distance and correct earthing and bonding, not through the containment itself.
Should data routes be wide and shallow or narrow and deep?
Wide and shallow, in most cases. The same cross-sectional area achieved through a taller profile stacks cables, which places the bottom layer under compression and raises temperatures within the bundle.
Can bends be formed on site on a data route?
They can, but the transition must respect the minimum bend radius of the cables being carried. Where that is difficult to achieve by field forming, a manufactured bend with a defined radius is the safer choice for structured cabling.
Specify for the link, not just the load
On a power route the containment carries the cable. On a data route it also influences whether the link certifies, how easily it can be changed, and how warm the bundle runs. Bend radius, separation width and single-layer placement are the three decisions that matter, and all three are made at specification stage.
CK manufactures wire mesh containment at a fully automated facility in Kemalpaşa, İzmir, and publishes cross-sectional capacity, weight and coating data for every width and side rail combination across the standard wire mesh cable tray range, in EG, pre-galvanized, hot dip galvanized and stainless finishes.
Send us your outlet count, cable types and route layout. We will return a tray size, a support spacing recommendation and the separation arrangement for any shared routes.
