Be Cautious of Midleading Claims Associated with YY and SY cables

Giuliano Digilio of ECA Today speaks to the British Approvals Service for Cables (BASEC) and the British Cables Association (BCA) to understand the issues surrounding YY and SY cables being used in fixed electrical installations in the UK.

There 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 with regard to what standards the YY and SY cable types conform to, if any, and misleading statements from some distributors.

The first issue to tackle is the perception of ‘YY’ cables. ‘YY’ simply means 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The UK standard for PVC/PVC flexible cables used to be ‘BS 6500’ which was withdrawn on 31st December 2012 and has now been replaced by ‘BS EN 50525-2-11’. Neither of these standards had nor has 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.

Of particular concern is the fact that these cables may not have any approval or had 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 to either 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, and to contact the BCA on 0208 946 69780208 946 6978 or email if you have any concerns. If you require cables to be checked and certified against the relevant standards contact BASEC via email: or call: 01908 26730001908 267300. For more information about BASEC services visit:

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