NAPIT Codebreakers #3

Need help with cracking those EICR codes? The technical team at NAPIT, with the help of the brand new 18th Edition Codebreakers publication, answer your latest coding queries.

DAVE CASHMORE: This was actually found inside my new-build house. I thought the spacing was strange on the MCB, then I noticed there was correction fluid hiding the ‘1’ on a 16A MCB to pass it as a ‘6’! The part number doesn’t lie…

CODEBREAKERS: This type of shortcut and attempt to disguise the wrong equipment type, because the correct equipment is not available, is wholly unacceptable. All that is being shown by the installer here is their poor installation design and planning, a lack of understanding of circuit protection, and a total disregard for the safety of the client and users of the installation. Evidently a 6A device wasn’t available or included in the CU kit, or the cost to return to site with the correct device was considered too costly; neither of these are credible or viable reasons for this kind of workmanship. There is no excuse for attempting to modify the markings of a device, to pass it off as something it isn’t. One saving grace could be if the conductors are clipped direct, as Table 4D5 allows 16A for 1mm2 and 20A for 1.5mm2, however, we must take account of the current rating of the accessories, which in most cases is 10A for plate switches, etc. As inspectors, this highlights the need to pay particular attention to devices and equipment, to spot this kind of behaviour. Always try and check individual part numbers; in this case, they clearly define the device’s true characteristics.

GARETH DAVIES: Saw this on a refurb job – four spurs wired off an existing ring, all supplying kitchen fixed equipment i.e. a spur off a spur off a spur off a spur, all in 2.5mm. No RCD on existing C/U either, what a surprise!

CODEBREAKERS: Unfortunately, this is a common sight. Failing to understand how to modify or add spurs to either a new or existing circuit, can have disastrous consequences, especially with the more consistent loads that can be associated in modern kitchen design. Spurs on radial circuits tend not to be a huge issue, as the Overcurrent Protective Device (OCPD) will take care of things in a correctly designed and installed circuit. Added to this the academically virtual unlimited number of spurs that can be added, and they don’t usually pose a problem.

Ring-final circuits (RFCs), however, require much closer attention to avoid potential problems. The Codebreakers publication gives in-depth guidance on spurs and additions to both radial and ring-final circuits for just this reason. In short, it is usually only acceptable to put one unfused spur onto an RFC socket-outlet or accessory. If fused spurs are used, the same rule applies, unless the first fused spur is solely supplying all of the other spurs. The first fused spur, in this scenario, would essentially protect upstream from large loads that could be applied by the downstream fused spurs.

Cable size is also very important when designing and modifying RFCs; spurs must be connected with appropriately rated conductors. Again Codebreakers gives clear guidance on this. Additional protection from a 30mA RCD for socket-outlets has long been a requirement for new circuits or additions, but we also have that requirement for cables buried at less than 50mm without mechanical or earthed mechanical protection. So, in any event, the new work in the photo requires protection via a 30mA RCD or protection in accordance with 522.6.204.

As this is new work and not technically code-able, it should be understood that all new work MUST comply with relevant building regulations and BS 7671. We cannot code new work as it is not allowable to energize known inadequate work, it must be corrected. In a perfect world that is fine, but if things haven’t worked out and a client is asking for a report on their install so far, then there should be no reason an inspector couldn’t carry out an EICR on this kind of scenario.