July of next year will see the publishing of the Wiring Regulations 18th Edition just to keep us on our toes. This is what we think will appear in the new BS 7671:2018 although once the report is actually published we will update the information for you and of course this will also be reflected in the exam simulator.
Here is a quick rundown of what we know now.
Likely changes will be the significant revision of Clause 443 informed by the recent publication of the IEC and CENELEC standard, delivered where consequences of overvoltage would affect:
- Human life
- Public services
- Industrial and commercial operation
- Protection for single dwellings in some cases (where electrical installation value protected amounts to five times less than the SPD value situated at the installation’s origin.)
Other risk assessment would be carried out to assess whether protection from transient overvoltage was needed.
Details for change included in the BS 7671:2018 are for arc fault detection devices (AFDDs) to counteract the fire risk in a fixed installation’s final circuit that may be the result of currents from arc faults.
Section 753 Changes
Section 753’s range will likely be expanded to apply to embedded surface heating electric heating systems, electric frost prevention heating systems or those used for de-icing or similar coverings in both outdoor and indoor systems etc.
Designers will have to show relevant information about the approved substances surrounding heating units with the standard for wall installation offering protection from overheating arising from live conductors short-circuiting due to any embedded heating units penetration.
For heating units directly delivered from manufacturer where there is no earthed conductive shield, a conductive covering, e.g. a metallic mesh grid, must be provided with subsequent connection to the electrical installation on site’s protective conductor. The IEC standard demands that electrical heating systems are chosen and installed avoiding any detrimental influence between non-electrical and electrical installations and the newly installed heating system.
The worldwide focus on energy consumption means consideration for providing optimum safety and service from electrical installations is necessary, at the lowest consumption. Draft proposals allow clients to request specific measures for energy efficiency for any electrical installation. Several areas of energy efficiency will be covered by the new section such as electrically powered vehicles, cable losses, metering, lighting, transformer losses, and harmonics and power factor correction.