18th Edition – is it fit for purpose?

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  Posted by: electime      14th October 2019

Almost a year has passed since the latest update was made to the 18th Edition regulations. However, questions remain as to whether the regulations are still fit for purpose and of value to modern electricians, particularly those working in industrial environments.

Whilst the updates included refreshed guidance around energy efficiency, approved parts, surge protection and arch fault detection, many of the changes had little relevance for electricians in the field and were aimed more at systems designers.

A large number of the updates detailed in the new regulations, for example, those relating to the installation and application of switchgear, could be considered an attempt to ensure that the new guidance accurately reflects the types of products and technology being used in industrial installations.

Ultimately, the updated 18th Edition regulations still constitute an essential source of information and guidance in any modern-day electrician’s toolkit. However, they contain a number of grey areas which are open to interpretation. Take, for example, the use of isolators on motors. According to the updated regulations 135.15.202 “Every fixed electric motor shall be provided with an efficient means of switching off readily accessible, easily operated and so placed as to prevent danger”. If this was taken literally, the installations could have potentially hundreds of motors, each with their own point of isolation nearby. In reality, this approach is neither logical nor feasible.

The regulation does however give the designer an option in that the efficient means of switching off can actually be remote from the motor, providing a safe system of work is in place to prevent danger. A better approach would be to define isolation requirements by current levels and locality to the power source, giving systems designers and industrial electricians more leeway in terms of where crucial isolation points are located.

It must not be forgotten that the 18th Edition regulations are a guide and are intended to be a ‘one size fits all’ approach. However, for younger, less experienced engineers, this can be cause for confusion as they are to some degree, open to interpretation. Newly-qualified electricians or those in training may find themselves faced with problems and situations on site which are not directly referred to by the guidance. In cases such as these, the individual is required to draw on common sense and experience to settle on a workable solution.

Some may argue that the lack of detail contained within the regulations limits their usefulness. However, turning them from ‘guidance’ into ‘rules’ could create further issues. A rule is inherently more prescriptive and considering the extremely diverse nature of industrial electrical applications, it would be a near impossible task to compile a single set of rules which would cover all eventualities.

One area of the 18th Edition regulations where there is clearly room for improvement is around some of the more specific sections, which would benefit for a degree of clarification. For example, there clearer distinctions should be made between the differing requirements for domestic, industrial and commercial installations. Of course, a large amount of the information, for example around earthing requirements, would remain the same. However, having set specifications for electricians working in different environments would be helpful in the long run.

Similarly, more detail should be given in the regulations about ‘Zs’ values, which represent maximum loop fault earth impedance. Currently, only the more commonplace figures are quoted in the 18th Edition, which rarely gives the level of information needed for industrial electricians. As the figures change, rather than waiting for a new edition of the regulations to be published, the amends could be issued as an addendum to the main document.

Lastly, there are some grey areas in the current publication around cable types. There are a number of IEC 60502-1-compliant cables, which are not necessarily coordinated with BS7671, the main UK wiring regulations. However, in the 18th Edition there are several blanket references, suggesting that all IEC 60502-1 cables may be of similar requirement to the British Standard. These parts are stated as informative (Appendix 4.1 for example) so they are not a regulation. Despite being a rather niche point, this distinction is important nonetheless, especially for less experienced electricians and designers in training.

The 18th Edition regulations form an important source of guidance and standardisation for electricians operating in a number of different environments. Whilst turning them from ‘guidance’ into ‘rules’ is not likely to benefit anyone, a number of refinements and clarifications would make them a more powerful and accessible tool for all of the UK’s electricians. Who knows what the 19th Edition may bring?

Tim McNeilly, managing director, I.C. Electrical