Cable Safety - Knowing Your Standards

NI Electrical spoke to Dr Jeremy Hodge, Chief Executive at British Approvals for Cables (BASEC), about what electricians should know about the different wiring regulations across Ireland – North and South.

There are slight deviations in the cable standards set by the Northern Ireland wiring regulations (UK IET wiring regulations, BS 7671) and the Republic of Ireland equivalent wiring code, ET101, that should be adhered to and fully understood by installers working around the various parts of Ireland and particularly across the borders.

Many of the cable types in use are similar, with cables made to either British (BS) or Irish (IS) standards. Cable types harmonised across Europe are now common, with many made to EN standards, such as the EN 50525 series.

However, there are sometimes minor technical differences, such as some standards requiring different testing requirements and also the ranges of size can differ. For example: BS 8436 is a screened cable and subject to a nail penetration test. The same cable type is identified by IS 273 (table 37) but the latter has a larger size range and higher voltage rating than its BS equivalent.

Also with regard to the coloured cores, ET101 regulations tend to be stricter than in BS 7671. Under ET101 the earth core has to be green/yellow while under BS 7671 it is permissible to end-label another coloured core with a green/yellow tag. Again under ET101 the neutral core must be wholly blue, but under BS 7671 a black core can be marked with two blue ends and hence be designated neutral. Some users in the UK are now adopting the Irish practice of whole length green/yellow and blue cores (for example in a three core cable), and amendments to British cable standards now make this possible without special certification from BASEC.

There have been some recent amendments to the Irish fire alarm system code of practice which has had the result of aligning the requirements of BS 5839-1 and IS 3218.

The main issue for contractors and electricians working across the borders is to use the applicable cable standard within that location or there could be repercussions from the customer. BASEC is pleased to support the market in the Republic just as it does in the UK, and has provided support for Irish standard committees, which in turn supports Irish manufacturers.

As well as understanding the wiring code for each location, electricians must help safeguard against the risk of installing cable which is substandard. Contractors should ensure that the cable supplied by the distributor is the correctly specified cable and check the markings on the cable and on the packaging.

When assessing cable markings look in particular for a recognisable or known manufacturer’s identification, so if there is a problem it will be possible to trace the cable back through the supply chain. Without a manufacturer’s stamp it is nearly impossible to trace the cable, therefore never accept cable without origin markings. For peace of mind, you should also insist on an independent third-party approved cable such as BASEC or HAR marked. It is also important to specify on your order the relevant standard number the cable should conform to.

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