White Papers

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Supporting Cables and Cable Management Systems – The change between 17th and 18th editions of BS 7671: Requirements for Electrical Installations.

FIA members may remember the presentation made at the FIA Summer Seminar and Networking Event in 2015 by Rob Cardigan in which he drew attention to the content of the 3rd Amendment of the 17th Edition of BS 7671 and its interpretation. We are now faced with revised text within 18th Edition of BS 7671, which again requires careful interpretation in order to assure compliance.

This White Paper seeks to clarify the situation, provide advice to members and is applicable to balanced as well as optical fibre cables.

Published January, 2019

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BS 6701:2016 was amended in October 2017 to include new “reaction to fire” performance requirements for cables inside buildings and these requirements were based upon products of a given “Euro”Class in accordance with the Construction Products Regulation. This was felt to be necessary because the 18th Edition of BS 7671 was intended to specify the requirements of LV power cables leaving the requirements for telecommunications cables to be specified within BS 6701.

Unfortunately, certain elements of our joint industries (including the British Cable Association in their Position Paper entitled “BS 6701:2016+A1:2017”) are confusing the situation by suggesting that telecommunications cables have to meet both the requirements of BS 6701 and BS 7671. This was never the intention of the proposals for the two documents.

This White Paper explains the background to the situation and lays out, in unequivocal form, the actual objectives.

Published November, 2018

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This White Paper has been developed following questions from members of the FIA concerning the performance of optical fibre cables which are advertised as being fire resistant. The principal issue is a lack of understanding of the conditions under which the specified transmission performance is delivered. For example, if a cable is advertised as being a fire resistant “Category OM3” cable, then when is OM3 performance delivered – before or during the fire? In almost all cases, it will only provide OM3 performance before the fire – and not during the fire.

The standards for testing of “fire resistant”, more correctly termed “circuit integrity”, cables allow a specified deterioration under certain fire conditions. Unfortunately some users do not realise this and expect the quoted transmission performance to be delivered under real fire scenarios. This can lead to contractual issues for FIA members supplying and installing such cables.

This White Paper seeks to clarify the situation, provide advice to members and is applicable to balanced as well as optical fibre cables.

Published November, 2018

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This paper provides information on the forthcoming changes to the way the optical fibres within the cables we regularly purchase and install are to be designated and highlights some concerns surrounding those changes.

For multimode optical fibre systems, the cabling standards of the ISO/IEC 11801 and EN 50173 series have a Category system OM3, OM4 and OM5 which relate to cabled optical fibre. The same approach is applied to cabled singlemode optical fibres of Category OS1a and OS2. Each of these cabled optical fibres are built from optical fibres in accordance with BS EN [IEC] 60793-2-10 (for multimode) and BS EN [IEC] 60793-2-50 (for singlemode).

The designation of the optical fibres in these standards are being changed with the objective of more closely linking the optical fibre to the wider market place.

Published November, 2018

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From 1st July 2017, all energy, communications and control cables that are placed on the market and intended to be installed in a “permanent” manner inside buildings and other structures have to be certified as being conformant to a specific EuroClass in relation to “reaction to fire”.

Annex A of this document provides some explanation of the EuroClass system.

The EuroClass itself does not dictate where the cables can be or may be used. Each country can decide this either via regulation, legislation or by the application of standards. In some countries, this will depend on building size, type or by the designation of the space inside the building.

In the UK, the standards that will define the application areas for cables are BS 7671 and BS 6701.The future contents of BS 6701 and BS 7671 are now becoming clear and this document provides guidance in relation to the management of the commercial impact of the CPR.

Published June, 2017

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The transfer of ownership of a cabling infrastructure (be it metallic or optical fibre) to a 3rd party is fundamentally different than a clients acceptance of such an infrastructure which has been subject to a supply contract. The latter relies on the terms of the supply contract – and a well written technical and acceptance testing specification will enable contractual disputes between the installer and the client to be resolved based upon the contents of that specification.

By comparison, the transfer of ownership of the cabling infrastructure to a 3rd party leaves the 3rd party in an unenviable position of not having been in control of the either the installation or its specification but being required to be responsible for its ongoing performance.

In such circumstances, there are number of steps that can minimize the risk of the transfer process and the 3rd party has to satisfy themselves that such steps have been applied – or to invest, possibly heavily, in backtracking to institute such steps if they have not already been applied.

This document provides an overview of the process. Detailed technical matters are left to other FIA documents.

Published May, 2017

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There are two primary sources of specification of singlemode optical fibre:
• the ITU-T G.65x series;
• IEC 60793-2-50 (published as BS EN 60793-2-50).

At the time of writing 20 different singlemode optical fibre specifications defined by the ITU-T. These are:
• ITU-T G.652.A, .B, .C and .D;
• ITU-T G.653.A and .B;
• ITU-T G.654.A, .B, .C, and .D;
• ITU-T G.655.A, .B, .C, .D and .E;
• ITU-T G.656;
• ITU-T G.657.A1, .A2, .B2 and .B3.

Each type has its own area of application and the evolution of these optical fibre specifications reflects the evolution of transmission system technology from the earliest installation of singlemode optical fibre through to the present day.

Published May, 2015

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The effect of lateral offset and angular misalignment in optical fibre connectors are analyzed as a function of fiber core diameter and wavelength. Model calculations are then compared to experimental results and discussed in relation with the used fibre type.

Published February, 2011.

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Optical harness procurement for space applications requires a good understanding of optical harness components. This white paper describes the component of such a harness and propose a systematic approach for procuring parts depending on individual space project situation. As a valued player on this market, Diamond present its implementation of such approach through products and quality grade concerning connectors and termination.

Published November, 2010