Hot-dip galvanized steel cable trays: a technical guide for demanding projects

In many industrial, infrastructure and energy projects, the question is no longer whether to use metal cable trays, but which finish to choose to ensure a long service life with minimal maintenance. In aggressive environments, the answer often points to hot-dip galvanized steel cable trays.

In this article, we explain what makes them different, how hot-dip galvanizing according to EN ISO 1461 relates to EN 61537 for cable tray systems, and in which types of projects it makes sense to specify this finish instead of pre-galvanized, electroplated or stainless-steel solutions.

1. What do we mean by hot-dip galvanized steel cable trays?

When we talk about hot-dip galvanized steel cable trays, we are not referring to one single tray design, but to the surface finish applied to different families of cable management systems:

• Wire mesh cable trays, like the ones described in detail in the article:
  PUK Wire Mesh Cable Trays: ideal for heat, high ventilation, and demanding environments
• Perforated and solid-bottom cable trays, already compared in:Perforated or Unperforated Cable Tray: Differences, Uses and Advantages
• Cable ladders and other self-supporting systems for long spans.
• Supporting structures and fixing elements that complete the installation (channels, brackets, threaded rods, clamps, etc.).

In all these cases, the base material is cold-formed carbon steel, and what really changes is the coating that protects this steel against corrosion. Hot-dip galvanizing is one of those coatings, but not the only one. Other common options are:

• Continuous (pre-galvanized) coatings - often called Sendzimir or pre-galvanized.
• Electroplated zinc (thinner coating, typical for low-aggressiveness indoor environments).
• Stainless steel (AISI 304 / 316) for very aggressive atmospheres or special hygiene requirements.
• Organic coatings (paint systems or duplex systems combining galvanizing + paint).

The goal of this article is to help you decide when it’s worth moving one step up and specifying hot-dip galvanized cable trays instead of options with a thinner zinc layer.

2. Hot-dip galvanizing according to EN ISO 1461 applied to cable trays

2.1. What the process looks like

EN ISO 1461 defines hot-dip galvanizing as the formation of a coating of zinc and/or zinc-iron alloy on iron and steel products by immersing the pieces in a bath of molten zinc at around 450 °C, after appropriate surface preparation (degreasing, pickling, fluxing).

During immersion, a metallurgical reaction between steel and zinc creates several Fe-Zn alloy layers strongly bonded to the steel core, topped by an outer layer of almost pure zinc. The result is not just a “thick paint”, but a coating integral to the metal, highly resistant to impact and abrasion.

For this reason, the surface appearance can vary:

• From bright grey with visible crystallisation (“spangle”),
• To a duller grey, depending on steel composition, immersion time and cooling conditions.

This aesthetic variation is not directly linked to the coating thickness or to the corrosion performance of the hot-dip galvanized layer.

2.2. Typical zinc thickness ranges

One of the key aspects of EN ISO 1461 is the relationship between base steel thickness and minimum average zinc coating thickness. For non-centrifuged articles, typical values are:

• Steel ≥ 1.5 mm and < 3 mm → ≈ 45 μm average zinc thickness.
• Steel > 3 mm and ≤ 6 mm → ≈ 55 μm average zinc thickness.
• Steel > 6 mm → ≈ 70 μm average zinc thickness.

These values are much higher than typical electroplated or continuous (Sendzimir) coatings, where total thickness is usually around 10-20 μm. That difference in zinc thickness is what translates into a significantly longer service life against corrosion.

2.3. Repairing cut edges and damaged areas

In real-world installations, cut ends, drilled holes or small uncoated areas are inevitable. EN ISO 1461 itself allows these areas to be repaired using zinc-rich paints or equivalent products, as long as a sufficient protective layer is ensured.

In practice, this means:

• Cut edges on cable trays should be touched up with cold zinc paint.
• The objective is to maintain cathodic protection and avoid exposing bare steel to the environment.

3. How EN ISO 1461 and EN 61537 work together in cable tray systems

In the world of metal cable trays and ladder systems, two standards are especially important:

• EN ISO 1461 → sets requirements and test methods for hot-dip galvanized coatings.
• EN 61537 → defines requirements for cable tray systems and cable ladder systems for cable management (load classes, safety, electrical continuity, marking, etc.).

In simple terms:

• EN ISO 1461 deals with how the steel is protected from corrosion.
• EN 61537 deals with how the cable tray system behaves (mechanical strength, deflection, tests, safety).

When you specify hot-dip galvanized steel cable trays according to EN ISO 1461 and EN 61537, you are covering two essential aspects:

1. Mechanical and functional performance: permissible loads, deflection, mechanical strength, impact tests, etc.
2. Corrosion protection: zinc coating thickness, adhesion and uniformity on all accessible surfaces.

In technical specifications and tender documents, both references often appear together, especially in:

• Transport infrastructure (tunnels, stations, car parks).
• Energy and heavy-industry projects.
• Installations in outdoor or highly humid/ aggressive indoor environments.

4. Key benefits of hot-dip galvanized steel cable trays

Why choose hot-dip galvanized steel cable trays over other finishes?

4.1. Higher corrosion resistance in aggressive environments

The zinc thickness provided by hot-dip galvanizing offers a reserve of zinc that is slowly consumed over time. This makes these systems particularly suitable for:

• Outdoor areas exposed to rain and UV radiation.
• Industrial atmospheres with pollutants and contamination.
• Coastal or marine-influenced areas (C4-C5 environments according to EN ISO 12944).
• Tunnels, car parks and spaces with frequent condensation.

In these conditions, a thin coating such as pre-galvanized (Sendzimir) or electroplated zinc can be insufficient, forcing early maintenance or even premature replacement of the cable trays.

4.2. Better resistance to impacts and handling

The zinc coating formed in hot-dip galvanizing is not only thicker, but also harder and more strongly bonded than many alternative coatings:

• It withstands impacts, rough handling and minor deformations better.
• It reduces the risk of chipping, which would create local corrosion hot spots.

For cable trays installed in high-traffic areas, warehouses or logistics zones, this robustness is a strong argument.

4.3. Lower maintenance requirements

In most environments, hot-dip galvanized trays offer decades of service life with very low maintenance, limited to visual inspections and small touch-up repairs when needed.

Compared to painted systems or purely organic coatings:

• There is no risk of large-scale paint flaking.
• The zinc layer still offers protection even when the surface becomes dull or shows superficial “white rust”.

4.4. Lower total cost of ownership

The initial investment in hot-dip galvanized steel cable trays can be higher than in pre-galvanized or electroplated trays. However, if you consider the total cost of ownership (CAPEX + OPEX):

• Fewer maintenance interventions.
• Fewer replacements due to premature corrosion.
• Higher reliability in harsh environments.

In long-term projects (infrastructure, tunnels, industrial plants, ground-mounted solar farms, etc.), the medium- and long-term savings often outweigh the initial cost difference.

5. When to specify hot-dip galvanized cable trays (and when not)

5.1. Typical situations where hot-dip galvanizing is the right choice

Field experience shows that hot-dip galvanized steel cable trays are clearly recommended in situations such as:

• Outdoor installations: industrial façades, technical roofs, pipe racks, external cable racks.
• Road and rail tunnels and other linear works.
• Marine or coastal environments with frequent salt spray or high humidity.
• Wastewater treatment plants, chemical plants and similar facilities, where atmospheres are humid and aggressive.
• Ground-mounted photovoltaic plants, where trays and supports are continuously exposed to the weather, UV radiation and dirt.

In all these cases, the priority is for the cable management system to remain mechanically sound for many years, even when the environment is unforgiving.

5.2. When stainless steel or other solutions may be more appropriate

There are scenarios where hot-dip galvanizing, although robust, may not be enough or may not be the optimal choice:

• Industries with very aggressive chemicals or extreme pH values.
• Environments with special hygiene and cleanability requirements (e.g. certain food or pharmaceutical areas), where stainless steel provides superior performance.
• Projects where duplex systems (hot-dip galvanizing + paint) are required for aesthetic reasons or for extreme corrosion categories.

In these cases, hot-dip galvanized trays may still be valid in some areas, but the final decision should be made together with the designer and the maintenance team.

5.3. When hot-dip galvanizing can be an over-specification

There are also projects where hot-dip galvanizing may be more than what is strictly necessary:

• Installations in dry indoor environments, without aggressive agents, where pre-galvanized or electroplated trays perform well if properly dimensioned.
• Secondary runs with low criticality and no exposure to corrosive atmospheres.

In such contexts, it can be more efficient to combine:

• Hot-dip galvanized trays in critical or exposed areas.
• Standard finishes in benign environments.

6. Practical criteria for selecting hot-dip galvanized steel cable trays

When specifying, it is worth going beyond “hot-dip galvanized tray” and looking at some practical criteria.

6.1. Steel thickness + zinc thickness = expected service life

As explained, EN ISO 1461 links base steel thickness with a minimum average zinc coating thickness. The thicker the steel, the thicker the zinc coating and, therefore, the longer the expected service life in a given environment.

From a specification point of view, it makes sense to indicate:

• Tray type (wire mesh, perforated, solid-bottom, ladder).
• Steel thickness (e.g. 1.5-2.0 mm).
• “Hot-dip galvanized according to EN ISO 1461”.
• Compliance with EN 61537 for the complete system.

6.2. Environment and corrosion category

Although corrosion categories (C1-C5, CX, etc.) are defined in other standards, a practical rule of thumb can be:

• Dry, clean indoor environments → standard finishes.
• Humid indoor environments or slightly corrosive atmospheres → consider hot-dip galvanizing or duplex systems.
• Urban/industrial outdoor areas, coastal environments or zones with frequent salt spray → hot-dip galvanizing as a minimum, and consider additional measures if the aggressiveness is very high.

The more aggressive the environment, the more interesting it becomes to combine good cable tray design (drainage, ventilation, correct spans) with a robust corrosion protection system.

6.3. Mechanical load and compatibility with supporting structures

Besides corrosion protection, the cable tray must carry cable weight and any additional loads safely.

Here, EN 61537 and the load tables in manufacturers’ catalogues are the reference for choosing:

• Tray height and profile.
• Type of supporting profile or bracket.
• Maximum permitted span between supports.

In critical installations (tunnels, data centres, large industrial plants), it may be highly beneficial to rely on static calculations provided by PohlCon Ibérica to validate spans and support configurations.

6.4. Fire resistance and circuit integrity

In certain projects, especially in infrastructure and complex buildings, cable routes must maintain circuit integrity under fire conditions (e.g. E30, E60, E90 according to fire protection standards).

In these cases, selecting hot-dip galvanized steel cable trays should go hand in hand with:

• System-tested solutions (tray + supports + fixings tested as a complete assembly).
• A design approach that considers temperature, expansion, mechanical behaviour and fire exposure time.

7. Application examples with PUK / PohlCon solutions

Without naming specific projects, there are three major application families where hot-dip galvanized steel cable trays fit particularly well with PohlCon Ibérica’s experience:

7.1. Tunnels and transport infrastructures

• Humid atmospheres, often with salts and pollutants.
• Need to combine long service life with demanding fire protection requirements.
• High cable volumes and stringent maintenance expectations.

7.2. Industrial parks and process plants

• Exposure to atmospheres with chemical agents, vapors or condensation.
• Power, control and signal circuits that must remain fully operational for many years.
• Strong need to minimize downtime due to cable tray corrosion or replacement.

7.3. Ground-mounted solar parks and outdoor technical areas

• Continuous exposure to UV radiation, rain, temperature variations and dirt.
• Need for a robust yet cost-effective solution.
• Integration with support structures designed to withstand wind, snow and other climatic loads.

In all these scenarios, combining a well-designed cable tray and support architecture with hot-dip galvanizing to EN ISO 1461 is a highly reliable long-term choice.

8. Installation and maintenance best practices

Choosing the right coating is important, but how the system is installed also has a strong influence on durability.

8.1. Handling and installation

• Avoid unnecessary impacts during loading, unloading and handling.
• Do not drag trays over rough surfaces.
• Use appropriate tools for cutting and drilling.

8.2. Treating cut edges and damaged areas

• Apply cold zinc paint to cuts and drilled holes made on site.
• Immediately repair any areas where the coating has been removed by impact or abrasion.
• Always follow the recommendations of both the paint manufacturer and the tray supplier.

8.3. Periodic inspection plan

Even though hot-dip galvanizing requires little maintenance, it is good practice to implement a visual inspection plan:

• Inspect the most exposed areas annually (or according to installation criticality).
• Detect early signs of localised corrosion or mechanical damage.
• Plan small corrective actions before they turn into major problems.

9. How PohlCon Ibérica can help you specify hot-dip galvanized steel cable trays

Each project has its own combination of:

• Environment (indoor, outdoor, coastal, industrial, etc.).
• Loads and distances between supports.
• Regulatory requirements (EN 61537, EN ISO 1461, fire protection standards, etc.).
• Site constraints and maintenance strategy.

At PohlCon Ibérica, we work precisely at the intersection of products, standards and real-world applications. Our technical team can help you:

• Choose the most suitable tray type (wire mesh, perforated, solid-bottom, ladder) and the right finish for each environment.
• Review routes, spans and support configurations using static calculations.
• Provide certificates and documentation for tenders and audits.
• Coordinate cable tray solutions with other systems such as underfloor installations, already covered in detail in:
  Underfloor systems: advanced guide for installation, standards and sector applications
  and Cable routing in data centers: cable trays and underfloor ducting.

If you are considering specifying hot-dip galvanized steel cable trays in your next project and want to be sure you are choosing the most appropriate solution, feel free to contact our technical team. We will be happy to review your case and propose the combination of cable tray and underfloor systems that best fits your needs.