Structured Cabling

November 30th 2017 saw the Publication of BS6701: Amendment 1, prior to its adoption as a supplement to the publication of BS7671 18th Edition of the IET Electrical Wiring Regulations in July 2018.

The objective of this standard is to improve the performance
of data & telecommunications cables reaction to fire.

The new BS6701: A1-2017 Standard now dictates the direction of where to install Telecoms cables (both copper and fibre optic variants) and governs a given Euroclass Cca–s1b,d2,a2 of cable construction in the permanent installation of these cables within a building.

This should be applied to all construction projects, either new build, refurbishment or the extension of existing buildings where installed cables are subject to the Construction Product Regulations.

Since the ratification of the Construction Product Regulations in 2017, there have been a number of options within the Euroclass Standards (see table below), and the choice of which to implement is left to each individual country within CENELEC to decide which construction is appropriate to meet the fire performance requirements of the building type on an individual basis.

However, BS6701 has specified the Cca Euroclass is the minimum Euroclass standard throughout the UK.

This is the most significant change to structured cabling and infrastructure design in over 12 years – act now to ensure you are up to date.


Category 5e has now been with us since 1992. Cat5e or class D is still the technology of choice for thousands of smaller local area networks (LAN) were, during the network’s lifetime, there is no likely need for greater than Gigabit Ethernet and, to be honest, in many offices and small companies, 100mb/s is still perfectly adequate and will be for some years.

Cat5e is also a great commercial choice for short-term networks were for example, a company cables-up a temporary or short term rented building – knowing that they only need the network for two or three years and then they’re moving out. So, for them, there is no commercial sense in future proofing the network.


Cat6 has never had an application (such as a specific speed of Ethernet) of its own. Instead, it became a significantly better solution for Gigabit Ethernet – offering the safety margin of ‘headroom’ that Cat 5e lacks.

With larger conductors, Cat 6 is also better for power over Ethernet (PoE) applications were its cables do not get as hot (and it should always be remembered that when data cables get warm it significantly degrades their data performance and the length of channel that can be supported!).

So, for installations where Gigabit is going to suffice for all foreseeable business or operational requirements (and where reliability rather than cheapness is the main driver) Cat6 is only a little more expensive than Cat5e but gives a much more robust engineering solution.


Cat 6A and class EA cabling systems have been deployed by forward-looking risk-hedging enterprises in both the backbone and the horizontal.

In enterprise backbones with links of 100m or less, 10Gb/s Ethernet is ideal with the cost of copper nic’s (network interface cards) about to become a fraction of those for fibre.

10GbE will undoubtedly become the network interface of choice for PC manufacturers – which means that Cat6A should be the cabling system of choice for the majority of organisations.

CCA Cables

There are many unscrupulous distributors now importing and selling Copper Clad Aluminium (CCA) cables as Cat5e and Cat6 but because they are not constructed of pure annealed copper conductors they cannot be classed as Cat5e or Cat6.

CCA has higher attenuation properties than pure copper cable and this will result in more packets of data having to be retransmitted when it is corrupted or lost at the physical layer. This effect is particularly prevalent on longer cable channels on or near the 100mtr maximum and will at best lead to a slower network for most users of CCA twisted pair cable.

Although no testing has been done on the use of CCA wire for Power over Ethernet applications the higher attenuation properties bring about some frightening possibilities, particularly in applications such as IP CCTV where power is continuously drawn through network cables 24 hours a day, 7 days a week, 365 days of the year using a cable with higher attenuation properties than intended for use with the IEEE802.3af standard, let alone IEEE802.3at, makes very real the possibility that heat will build up faster than it can be dissipated with potentially disastrous consequences

Fibre Optics

The following are Ethernet applications supported by different classes and categories of fibre optics and their maximum channel lengths.

Ethernet ApplicationOM1OM2OM3OM4
1000Base-SX (Gigabit)275m550m550m1100m
10GBase-SR/SW (10 Gigabit)32m82m300m550m
Ethernet ApplicationOS1OS2
1000Base-LX (Gigabit) 2,000m5,000m
10GBase-LX4 & LR/LW (10 Gigabit) 2,000m10,000m
10GBase-ER/EW (10 Gigabit)2,000m 22,250m