18th Edition: Why manufacturer approval matters

With the 18th Edition of the IET Wiring Regulations comes new recommendations as well as increased levels of regulation. It’s important to understand what is being asked of installers, explains Jim Hutchinson, national sales manager for Electrium brands Wylex and Crabtree.

One of the new regulations, 536.4.203, states that devices and components that are used in low voltage assemblies (to BS EN 61439) such as consumer units and distribution boards must only be those that have been declared suitable for that purpose by the manufacturer of the assembly. Or put another way: only use manufacturer approved parts, don’t mix brands of devices or control items.  

Each manufacturer of electrical switchgear designs and tests its own products for use in combination with each other, not with other brands. So if someone were to use a mixture of brands, they would be creating an untested assembly and untested assemblies aren’t backed by manufacturer guarantees. 

Obviously, no manufacturer can guarantee an installation that hasn’t been completed in-line with the manufacturer's installation instructions. But that doesn’t mean that manufacturers won’t permit control items to be added to an assembly. 

Readers should be aware that the notes relative to 536.4.203 state that if the assembly deviates from the original manufacturers' instructions, then the person introducing that deviation becomes the manufacturer. So if you have an installation that requires non-standard arrangements, talk to the manufacturer about how to provide this in a compliant manner. Using unapproved parts will invalidate manufacturer guarantees and may result in an unsafe installation.

As of the 1 January 2019, the new 18th Edition regulations must be used in all designs and installations. The changes introduced by the 18th Edition presents some new opportunities for the industry. These include further safety measures for installers to provide for their customers, as well as a focus on energy efficiency.

Designers and installers should obtain their own copy of BS7671:2018 and follow the requirements and recommendations in the 18th Edition of the IET Wiring Regulations.