Cable routing in data centers: technical guide to cable trays and underfloor ducting

The boom in cloud, e-commerce, streaming and now AI and advanced analytics has driven up power density and the complexity of cabling in data centers. In this scenario, any weak link in routing from the cable tray to the last underfloor outlet unit can turn into downtime, higher operating costs and reputational damage. The good news: designing cable routing in data centers with sound technical, regulatory and maintenance criteria prevent risk and enables growth.

Unlike approaches focused only on “management” (tidiness, ties, labeling), this guide addresses the complete routing architecture: tray selection (wire mesh, solid/perforated, ladder, long spans), supports, compatible accessories, product testing (e.g., DIN EN 61537) and passive fire protection (DIN 4102-12 E30-E90), integrating underfloor ducting systems as a natural complement for IT rooms, NOC and technical offices.

Why cable routing is critical (not merely “aesthetics”)

• Service continuity: how cabling is routed, segregated and supported determines MTTR, the ability to intervene without shutdown and overall resilience.
• Thermal behavior and efficiency:ventilated routes reduce hot spots and help maintain effective airflow around cable bundles; choosing the right trays and routes directly impacts cooling.
• Safety and standards:cable tray systems tested to DIN EN 61537 provide mechanical/functional assurance; for critical routes, E30-E90 circuit integrity requires a complete system (tray + supports + fixings + fasteners) tested as a whole.
• Maintainability and scalability: routes with proper bend radii, power/data segregation, capacity reserves and well-planned underfloor access shorten intervention times and ease migrations (e.g., to 100G/400G).

Design principles: from rack to room… and to the building

1) Trunk routes and functional segregation

Define trunk routes and contingency routes, segregating power from data with separators and compartments where needed. Avoid unnecessary crossings and keep copper/fiber bend radii to protect performance. These practices reduce operational errors and speed up incident resolution.

2) Ventilation, heat dissipation and order

In IT rows, favor solutions that promote ventilation of the cable bundle. Jammed or poorly contained cabling raises temperatures and narrows cooling margins; open trays and well-sized routes help stabilize the thermal environment.

3) Selecting the cable tray system (with testing)

Not all trays are the same: select by load, span, environment, ventilation, accessories and regulatory compatibility. PUK/PohlCon cable tray systems are tested to DIN EN 61537, ensuring verified performance.

4) Passive fire protection (E30-E90) where required

If a route must maintain circuit integrity during a fire, specify E30-E90 under DIN 4102-12: all components (trays, supports, fixings, fasteners) must be compatible and tested together. Avoid mixing generic accessories that invalidate the classification.

5) Underfloor as an operations lever

In NOC and technical offices, underfloor ducting provides access points, modularity and tightness where needed. The PUK/PohlCon catalogue includes flush-floor ducts, boxes and outlet units, elbows, tees and protection sleeves for fire/smoke, with complete system diagrams for planning.

Cable trays in data centers: types and when to choose each one

Objective: achieve safe, ventilated, easy-to-maintain and standards-compliant routing.

A) Mesh cable trays (basket)

• Superior ventilation and flexibility for in-situ take-offs and direction changes; ideal in IT rows and hot/cold aisles.
• Integrated joining systems reduce accessories and installation time, minimizing weak points and speeding up deployment and future expansions.
  When to choose it: IT rooms, short vertical drops, sections where airflow and agility are the priority.

B) Solid / perforated

• Greater mechanical protection and controlled containment (useful in environments with dust/spills or for certain EMI strategies).
  When: power sections, areas with mechanical risk or transitions to non-IT zones.

C) Ladder and long spans

• Handles high loads with long spans and fewer support points; ideal as the room’s backbone or for risers.
  When: power trunks, main routes, heavy verticals.

Key standard: choose systems tested to DIN EN 61537 and follow the catalogue’s load/height/support tables.

Underfloor ducting: the silent ally of operations

Routing does not end “overhead.” In NOC, technical offices, labs and ancillary rooms, underfloor ducting provides access points and relocations without construction works:

• Flush-floor and raised-floor ducts, with boxes and outlet units (power/data).
• System components: elbows, tee/cross junctions, separators, joints, fire-protection sleeves, smoke caps, levelers, earth terminals.
• System diagram: the catalogue includes diagrams and family tables with dimensions, included accessories and options.

Operational benefits:

1. Maintainability: clean re-entries and workstation mobility.
2. Safety: tightness and sleeves for protected penetrations.
3. Capacity: sections sized for modern densities, with power/data separators.
4. Integration: coordination with overhead trays for tidy drops to the workstation.

Safety and continuity: E30-E90 on critical routes

In data centers and critical buildings, routing is not just “taking a cable from A to B”: some routes must maintain circuit integrity during a fire to ensure evacuation, alarms and essential systems.

• DIN 4102-12: evaluates the fire behavior of the complete system, assigning E30, E60, E90 according to minutes of integrity.
• Compatibility: trays, supports, fixings and fasteners must be tested together. Avoid mixing third-party accessories.

Recommendation: define critical corridors with E30-E90 systems, separate redundant routes, and avoid paths through high thermal-load areas where feasible.

From theory to the room: practical integration

1. Room backbone using ladder/long-span tray (400-600 mm) with 3 m spans and adequate supports.
2. IT rows with wire mesh (100-200 mm) for ventilation, agile take-offs and power/data segregation by separators.
3. Side/rear verticals with U-shaped wire mesh or similar for clean drops to the rack.
4. NOC/technical office areas with underfloor duct (modular families) and boxes for outlet units; consider protection sleeves where required.

12 frequent routing mistakes (and how to avoid them)

1. Not planning future capacity (keep 20-30% reserve in section/support).
2. Mixing non-tested accessories → invalidates E30-E90 classification where applicable.
3. Lack of power/data segregation.
4. Non-compliant bend radii in fiber/copper.
5. Too many accessories in wire mesh; favor integrated joints for fewer weak points and shorter installation time. (e.g., EASYCONNECT Basket Tray^®)
6. Compromised airflow due to closed trays in sensitive IT areas.
7. Undersized supports for actual load/spans.
8. Lack of documentation and labeling (impacts MTTR/uptime).
9. Routes without maintenance access.
10. Underfloor without tightness and without earthing where required.
11. Redundant crossings and unnecessary plane changes.
12. No coordination with facilities (HVAC/fire protection) and with the building (seals, penetrations).

Indicative specification (tender template)

• Cable tray system (DIN EN 61537):
  Backbone in ladder/long-span (width 400-600 mm), 3 m span, loads per catalogue; ceiling/wall supports with approved fixings.
• IT rows:wire mesh 100-200 mm with power/data separators; integrated joints; covers only where the environment requires it.
• Transitions:solid/perforated in sections with mechanical risk/containment.
• Passive fire protection (if applicable):E30-E90 (DIN 4102-12) with a complete tested system (trays + supports + fixings + fasteners + arrangement).
• Underfloor ducting: modular ducts with boxes for outlet units and protection sleeves; include earthing and smoke caps where appropriate.
• Finishes:hot-dip galvanized / stainless steel according to atmosphere and cleanliness requirements.
• Documentation:as-built drawings, labeling/routing and dossier of system tests/compatibilities.

Typical use case (mid-to-large scale | 150 racks)

• Main routes: two 600 mm ladder trunks along the technical corridor, with physical redundancy.
• Row drops:150 mm wire mesh with separators and side drops; in-situ take-offs.
• Fire protection: alarm/evacuation routes with E30-E90; seals coordinated with the building.
• Underfloor (NOC/offices):two-compartment duct (300-500 mm) with boxes and outlet units; sleeves in penetrations with the required rating; system diagram and bill of materials per the PUK catalogue.

Prescription checklist

1. Current density and at 36 months (capacity and sections).
2. Tray type by load/span/airflow/environment (wire mesh, ladder, solid/perforated).
3. DIN EN 61537 compatibility (cable tray system).
4. Is E30-E90 required? If yes, DIN 4102-12 with a complete tested system.
5. Power/data segregation, bend radii and earthing.
6. Underfloor (ducts, boxes, outlet units) and tightness.
7. Compatible supports and fixings; do not mix accessories outside the E30-E90 system.
8. Documentation and labeling (routes, panels, racks).

Glossary of key terms in data centers (DC)

DC (Data Center / CPD):
Physical facility that houses servers, storage, cabling, HVAC and security. It is the technological heart where an organization’s digital services are managed and protected.

NOC (Network Operations Center):
Network operations center. Room dedicated to 24/7 monitoring of network infrastructure and systems. Incidents are detected in the NOC, traffic is supervised and service continuity is ensured.

Backbone:
The DC’s backbone. Refers both to the main electrical cable routes (ladder or long-span trays to carry power) and to the network backbone (high-capacity trunk connections over fiber/copper).

Hot aisle / Cold aisle:
Room design that arranges racks in facing rows, creating cold-air and hot-air aisles to optimize cooling and energy efficiency.

N+1 redundancy:
Configuration of critical systems (power, HVAC, networks) where at least one backup component is added to those required for operation. Ensures continuity even if one element fails.

E30-E90 (circuit integrity):
Fire-resistance classification under DIN 4102-12. Indicates that an electrical routing system (tray + supports + fixings) maintains circuit integrity for 30, 60 or 90 minutes.

Are you designing or upgrading a Data Center?

Request a free technical review of your routing layout (loads/spans, standards and underfloor). We will propose the optimal combination of tray + underfloor and deliver a ready-to-buy bill of materials, with engineering support during installation.

Product resources (download)

Cable tray catalogue (PUK/PohlCon) - wire mesh, solid/perforated, ladder, long spans. (Download PDF)
 

Underfloor systems catalogue - flush-floor ducting, outlet boxes, units and sleeves; system diagrams and dimensions. (Download PDF)