[ Update: Cables ]
CABLE CAUTION T
Watch out for misleading claims associated with YY and SY cables
GIULIANO DIGILIO, ECA head of Technical Services, has been speaking with the British Approvals Service for Cables (BASEC) and the British Cables Association (BCA) to understand the issues surrounding YY and SY cables
here is a concern in the market place that flexible cables, including YY and SY types, are being used in fixed electrical installations. The concern arises from a number of misunderstandings over
what standards, if any, the YY and SY cable types conform to, and misleading statements from some distributors. The first issue to tackle is the perception of YY cables. ‘YY’ simply means that the insulation and sheath materials are PVC and does not imply compliance with any particular standard. The term ‘YY’ is being used as if it is a recognised type of cable under the IET Wiring Regulations, which is not the case. YY cables are made generally – but not necessarily exactly – to a German standard. However, there is often no specification (published standard) quoted on the cable, so it is impossible to determine whether the cable actually complies with a published British Standard, or UK adoption of a CENELEC standard. The UK standard for PVC/PVC flexible cables used
to be BS 6500, which was withdrawn on 31 December 2012 and has now been replaced by BS EN 50525- 2-11. Neither of these standards had, or have, PVC cables rated higher than 300/500V (ordinary duty), so claims of 450/750V cables being ‘generally to BS 6500’ and certainly ‘YY flexible cables to BS 6500’ from distributors are misleading. We have also noticed this happening with the similar SY cables (steel braided, colourless jacket). Whilst PVC/PVC flexible cables are now included in part of the BS EN 50525 series of harmonised European cable standards, it cannot be concluded that this covers any or all YY types. PVC/PVC cables should always be referred to by their European harmonised code designation (for instance, H05VV-F), or the original UK national code (for instance, 3183Y). Of course, any appropriate cable conforming to a harmonised European standard can automatically be used under clause 511.1 of the IET Wiring Regulations.
Approval and testing Of particular concern is the fact that these cables may not have any approval, or have had
54 ECA Today September 2013
Of particular concern is that these cables may not have any approval or have had any independent testing performed
any independent testing performed. Users are, therefore, urged to ensure they purchase cables with manufacturers’ identification and a specification reference printed on the jacket, to enable testing and traceability, if necessary. We are aware that some distributors make questionable claims of compliance for these cables to some British Standards.
If the cables do not conform either to a British or harmonised standard – or where the cable is to be used outside the scope of its standard – then the system designer and/or installer should confirm that at least the same degree of safety is provided as that afforded by compliance with the Wiring Regulations (see clauses 511.1 and 511.2). This should cover the use to which the cable is put and the impact of external influences. Where, for example, an armoured cable is replaced by an SY cable, then the level of mechanical protection is not the same and additional measures may be needed. We therefore urge extreme caution in accepting the use of YY and SY cable types for UK fixed installations. If you have any concerns, contact the ECA technical department on 020 7313 4833 or the BCA on 0208 946 6978, or email
peter.smeeth@
btconnect.com. If you require cables to be checked and certified against the relevant standards, contact BASEC via email at
technical@basec.org.uk or call 01908 267300. For more information about BASEC services, visit
www.basec.org.uk
n Thank you to Dr Jeremy Hodge, chief executive of BASEC and Peter Smeeth, secretary general at the BCA.
BASEC approved cable in the BASEC laboratory
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