Cat6A Internal and External Cables: A Practical Installer Guide to Grades and Environments

Cat6A cable is the right technical choice for many modern structured cabling projects in Ireland, but ordering the wrong grade for the environment is a common mistake that can create fire compliance problems, cable degradation, and long-term performance issues. This guide explains the key Cat6A grades available in the CNET range, when each applies, and what Irish building regulations require.

Cat6A Cable Grades: What They Mean

The category (Cat6A) defines electrical performance. The grade defines the jacket material and environment suitability. These are independent specifications, and a cable can be Cat6A in several different grades.

LSZH vs PVC: The Irish Building Regulation Requirement

Technical Guidance Document B (Fire Safety) under the Building Regulations 2000 (as amended) governs cable fire performance requirements in Irish buildings. The key principle is that cable jackets in areas used for escape, such as corridors, stairwells, lobbies, and ceiling voids above escape routes, must not generate toxic or excessive smoke in the event of a fire.

PVC jacket cable, when combusted, generates hydrochloric acid gas, a serious respiratory hazard. LSZH cable jackets are formulated to minimise smoke and eliminate halogen compounds, substantially reducing the toxic hazard in a fire.

In practice, many contractors specify LSZH throughout a project for simplicity, eliminating the need to track which zones require which jacket material. CNET Cat6A LSZH is available at marginal additional cost over PVC.

For a wider overview of how these fire performance rules sit alongside the rest of the structured cabling standards landscape in Ireland, see this guide to data cabling standards in Ireland.

Specify LSZH when any of the following apply

• 1The project specification calls for LSZH, which is standard in public-sector and OGP framework projects
• 2Cable runs through corridors or stairwells that form part of the means of escape
• 3Cable is installed in ceiling voids above occupied or escape-route areas
• 4Healthcare facilities are involved, where HIQA and HSE specifications typically mandate LSZH throughout
• 5Education projects (primary, secondary, third level) fall under DEIS and building guidelines that generally require LSZH
• 6Any area with limited egress or high occupant density

External Cat6A: When Fibre Is Not the Answer

For campus links and building-to-building connections, multimode or single-mode fibre is generally the first choice. It is immune to interference, has no distance limits on a single run, avoids ground-loop issues between buildings, and is physically smaller. However, external Cat6A has a legitimate role when:

• Run length is under 90 m and the cost of fibre termination and media conversion is not justified
• An existing copper backbone infrastructure needs to be extended without introducing new termination technology
• A single-building installation needs an outdoor section, such as car park camera runs or external access control
• Budget constraint is significant and the performance requirement is clearly within Cat6A copper range

External Cat6A Installation Requirements

• Always install in conduit where possible: HDPE conduit for underground, galvanised steel for exposed surface mounting
• Ensure conduit is sealed at building entry points to prevent moisture ingress and gas migration
• Use approved outdoor-rated gel-free or gel-filled cable depending on direct-burial requirement
• Maintain minimum bend radius throughout: external Cat6A has the same bend radius requirement as internal (4x OD)
• Allow for expansion and contraction in exposed outdoor routes, and leave a service loop where the cable enters the building
• Use outdoor-rated patch panels or terminate directly to outdoor-rated enclosures at both ends

CNET Cat6A Grade Summary

CNET Cat6A range for Irish and UK installers:

• Cat6A UTP LSZH Internal: ISO/IEC 11801 Class EA, LSZH jacket, 305 m reel, available in multiple colours
• Cat6A UTP PVC Internal: ISO/IEC 11801 Class EA, PVC jacket, 305 m reel
• Cat6A F/UTP LSZH Internal: screened, ISO/IEC 11801 Class EA, for EMI-sensitive environments
• Cat6A UTP External UV: HDPE UV-stabilised jacket, suitable for conduit outdoor routes
• Cat6A UTP Direct Burial: gel-filled HDPE jacket, rated for direct burial without conduit

A 25-year system warranty is available on all grades when installed as a full CNET channel by a registered installer.

Common Mistakes to Avoid