Cable tray or conduit? When should you use each one?

Last updated: October 21, 2026

Use cable trays when you have a large number of cables or large-diameter cables running together in a main route, and you need ease of addition and maintenance later. Use conduit for smaller, branch circuits, for running within walls and concrete, and in areas exposed to impact or where people can reach. In most projects, both systems work together: cable trays for the main routes and conduit for the final branches.

What is the main difference between cable trays and pipes?

A cable tray is an open or semi-open support structure, mounted on walls or suspended from the ceiling, onto which cables are laid and tied. Its primary function is to support and organize cables, not to completely enclose them. A conduit, on the other hand, is a closed tube into which the cable is pulled, protecting it from impacts, moisture, and tampering, but it limits the number of cables that can be laid and makes future additions more difficult.

If you want to learn about the different types of trivets themselves (perforated, solid, ladder, and mesh), see the article What is a cable tray and what are its types?Because the choice of type comes after the "tri-am-pipe" decision.

Common pipe types in projects

• PVC pipes: Lightweight, easy to install and rust-free, it is widely used inside walls, ceilings and concrete in residential and commercial buildings.
• Galvanized metal pipes (solid or thin-walled): It provides higher mechanical protection and is used in factories and exposed, impact-prone areas.
• Flexible pipes: For short connections to motors and equipment that vibrate or move slightly.

When is a cable tray the best option?

Trays excel when a project is large and involves a large number of cables. Key examples:

• Main routes in factories and warehouses: From the electrical room to the distribution panels and production lines, dozens of cables run together.
• Large power cables: Pulling a cable with a large cross-section inside a long pipe with bends is a laborious process, while it is easily laid out on the tray.
• Electrical, communications, and server rooms: Connections are constantly changing and require quick access to each cable.
• Commercial solar systems: Assembling and transferring DC panel cables to inverters and then to distribution boards, especially on large roofs and ground-level structures in projects. Solar energy for factories and facilities.
• Projects expected to be expanded: Adding a new cable to an existing tray requires nothing more than unrolling and connecting it, as long as the fullness level allows.

A cooling feature that many overlook

Every cable heats up when current flows through it, and its current-carrying capacity depends on how quickly it dissipates this heat. Cables laid on a perforated or ladder-type tray allow air to circulate around them, while cables bundled inside a closed conduit accumulate heat. Therefore, cable selection tables apply reduction factors for bundles and laying methods, and the same cable may require a larger cross-section if laid inside a conduit with other cables. In hot summer weather, this difference has a significant impact on cost.

When are pipes the right choice?

• The few sub-districts: Lighting, sockets, and terminal connections for one or two devices, where the number of cables does not justify installing a tray.
• Hidden extension: Inside walls, ceilings, and concrete slabs, it is primarily the field of pipes.
• Places vulnerable to impact or tampering: Low walls in warehouses where forklifts pass, and public areas that people access.
• Damp or dusty places: Cables require a sealed sheath, with appropriate connectors and seals.
• Dangerous areas: Such as places containing flammable gases and vapors, and these have special requirements regarding the type of pipes and connections, which are determined by a specialized engineer.

Pipe constraints that must be taken into account

Conduits have much smaller fill limits than treads because cables need space to be pulled without damaging their sheath. Many codes, including the American NEC code, specify a fill limit of 40% of the conduit cross-sectional area when there are more than two cables, and also limit the sum of the bend angles between two pull points. In practice, this means more pull boxes and more conduits as the number of cables increases.

Comparison table: Cable tray vs. pipes

Standard	cable tray	pipes (Conduit)
appropriate number of cables	Large, and large-section cables	A few, and sub-circles
Mechanical protection	Medium, and increases with the cover or solid type.	High, especially mineral
Heat dissipation	Good at drilling and laddering	Weaker with cable bundles
Add cables later	Easy as long as the capacity allows	Difficult and may require a new pipe
Inspection and maintenance	The cables are visible and easy to trace.	The cable is hidden and needs to be pulled out for replacement.
Hidden extension	unsuitable	Suitable for use inside walls and concrete
Cost on busy routes	Less often per cable	It increases with the number of pipes and suction boxes.

Is any cable suitable for extension onto a cable tray?

Not always. Cable laid on an exposed tray must be designed for that purpose, meaning it has an outer sheath to withstand the surrounding conditions and, outdoors, UV radiation. Unsheathed single-core wires used indoors are designed to be run through conduits or enclosed ducts, not laid on an open tray. Therefore, the cable type and the type of support are determined during the design phase, not on-site.

For outdoor, sun-exposed applications, such as rooftops and solar panels, hot-dip galvanized cables with a top cover are preferred. This reduces direct sunlight exposure and protects the cables from dust accumulation. Details on the differences between galvanizing types can be found in the article. Hot-dip galvanized or electro-galvanized cable.

Common solution: Combining the tray and pipes

In a typical factory or warehouse, cables exit the electrical room on a raised main conduit, from which smaller conduit routes branch out to the production areas. Upon reaching each machine or sub-panel, the cable passes into a metal or flexible conduit that protects it at the end exposed to movement and impact. This combination offers both conduit capacity and conduit protection.

For the merger to be successful, pay attention to:

1. Use appropriate connectors when the pipe comes out of the tray, so that the cable does not rub against a sharp metal edge.
2. Leaving spare capacity in the main tray for future expansions.
3. Grounding the trays and metal pipes and connecting them electrically according to the approved plan.
4. Separate power cables from communication and control cables, either with a divider inside the tray or with independent paths.

To determine the appropriate tray width and height for your number of cables, try Cable Tray CalculatorThey give you the suggested size and a list of materials initially before you request a quote.

How do you make decisions in your project?

Ask yourself these questions in order:

1. How many cables are in this route, and what are their cross-sections? If there are many or large cables, the TRAIN is preferable.
2. Is the path hidden inside a wall or concrete? If so, pipes are the solution.
3. Is the track subject to impacts, tampering, or access by people? Metal pipes or a solid tray with a cover.
4. Are cables expected to increase in the future? The Tri-C saves you from having to redo the work.
5. Is the type of cable chosen suitable for exposed wiring? If not, either change the cable or use a conduit.

The final decision in large projects rests with the design engineer and is based on the approved project specifications and requirements. You can review the specifications. The cable tray is manufactured by MITS. To find out the available sizes and thicknesses.

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