18th Edition of the IET Wiring Regulations (BS7671)

The 18th Edition of the IET Wiring Regulations (BS7671) comes into force from January 1, 2019. That means construction site managers, health and safety managers, electricians and electrical contractors need to be fully compliant and up-to-date with the new BS7671 wiring regulations – especially in relation to how cables are supported in the event of a fire.

The new 18th Edition wiring regulations (https://electrical.theiet.org/bs-7671/18th-edition-changes/) include updates designed to reduce the risk of death from the placement of hanging cables. The aim is to improve installation safety using the adequate placement of metal clips to support hanging cables. Other updates in BS7671 include new RCD protection requirements and recommendations for installing Arc Fault Detection Devices (AFDDs).

If you’re a construction site manager or a health and safety consultant or manager, it pays to be fully aware of the new wiring regulations – especially if you’re responsible for cable fixing installation across a site. Electricians or electrical contractors installing, hanging or suspending electrical cabling will need to meet full wiring regs compliance by January 1, 2019. This article explains what the new 18th Edition wiring regulations mean in terms of fixing and suspending electrical cables.

Why have the 18th Edition wiring regulations (BS7671) been changed?

Known as Regulation 521.10.202, the aim of the new wiring regulations regarding the fixing of hanging cables is to reduce the risk posed by suspended cables in the event of a fire. The change of wiring regs follows the death of two firefighters at Shirley Towers in 2010 who became entangled in fallen cables. Two firefighters also lost their lives in 2005 at Harrow Court Tower Block (https://www.fbu.org.uk/news/2007/03/02/fbu-comment-end-coroner%E2%80%99s-inquest-deaths-harrow-court-stevenage-herts), where one of the firefighters had become entangled in fallen electrical cables.

The 18th Edition wiring regulations aim to avoid similar incidents. This is especially true with high-rise building developments, where fires have devastating potential – a priority for construction site managers or a health and safety consultant or managers.

The risk of fire on construction sites (http://www.constructionmanagermagazine.com/construction-professional/cpd-fire-prevention-construciton-sites/) should also be a consideration when managing cables. Although not common, when construction sites fires occur the materials exposed and contained within a site mean that fire can spread rapidly. Knowing how cables can be better managed can reduce to risk to workers on site as well as emergency service crews.

What do the 18th Edition wiring regulations (BS7671) require?

The new wiring regs come into effect in January 1, 2019. The 18th Edition states that plastic fixings cannot be used as the sole use of holding up cables. However, the IET states: “Suitably spaced steel or copper clips, saddles or ties are examples that will meet the requirements of this regulations.” This means that plastic fixings can be supplemented with metal ones – but that electricians and electrical contractors cannot rely exclusively on plastic clips, saddles or ties.

This also applies to temporary cables

The 18th Edition wiring regulations apply to all types of cable installation and not just escape routes such as fire exits. Regulation 521.10.202 now requires cables to be adequately supported against their premature collapse in the event of a fire. It applies to all types of cable that could fall in the event of a fire. This means that cables fixed against a wall (that don’t cover a doorway) can be supported fully by plastic fixings as if the cable fell in a fire, it would fall to the corner of the corridor and not trap anyone.

What type of cable supports does the 18th Edition wiring regulations allow?

This part is left open to interpretation – Regulation 521.10.202 calls for ‘adequately supported’ cables – and we feel that it would be better if the IET would clarify with a clear definition of what ‘adequately supported’ means. However, experts consider the new wiring regs call for metal cable supports to ensure compliance. This includes all cable supports such as cable trays, baskets, hangers and hooks.

Does the 18th Edition ban the use of plastic cable fixings?

Plastic fixings are not banned and can be widely used throughout the industry as a cost-effective way to manage cables. However, plastic cabling fixings can no longer be used as the sole means of securing cables in place.

This will affect the sole use of products such as:

Cable ties
Cable clips
Plastic conduit (with plastic fixings)
Plastic trunking
Plastic fixings holding up cable tray
Plastic cable hooks and hangers

Existing plastic cable management solutions will need to be supplemented by metal fixings to ensure they’re not the ‘sole means of supporting’ cables.

Does the 18th Edition wiring regulations apply to existing cable installations?

The Regulations apply to the design, erection and verification of electrical installations, as well as additions and alterations to existing electrical cable installations. The good news for construction site managers and health & safety consultants/managers is that existing installations that have been installed in accordance with earlier editions of the Regulations do not need to be replaced. This change is not retrospective and any installations fitted before 1st January may still be compliant.

The new regulations have been welcomed by the fire services. According to Charlie Pugsley of the London Fire Brigade’s Fire Investigation Team: “We believe it’s essential [521.10.202] because … we’ve lost three firefighters in the course of firefighting operations, where the clips have become damaged by fire and cables have dropped and then crews have become entangled. We feel this is a really good, positive step to improve safety for our officers and also for the public”.

Alarmwise UK