In an ever growing world of efficiency demand the 18th edition has now dedicated a whole appendix to it; Appendix 17 makes recommendations for the design construction & assembly of the installation for optimizing efficiencies in the use of electricity.
Reading through the scope they have only been a few slight amendments however the main change that stands out is “Skilled person” in replace of competent person.
This now reduces DIYers and novices from making alterations or installing new circuits and will reduce risks and avoid hazards which electricity can create.
Chapter 46 is back
Chapter 46 Devices for isolation and switching has been re-introduced which focuses on non-automatic local and remote isolation and switching measures for the prevention or removal of dangers associated with electrical installations or electrically powered equipment. Also, switching for the control of circuits or equipment. Where electrically powered equipment is within the scope of BS EN 60204, only the requirements of that standard apply.
There are several new definitions, and a few existing definitions that have been amended. For example, “Discrimination” has been replaced by selectivity, although the meaning remains the same. “Departures” is new and can be utilized during the design approach in certain circumstances, where used they must be agreed be all parties to a contract.
Non-compliance: a Non-conformity that may give rise to danger.
This seems to be one of the biggest amendments in particular, <30mA RCDs will now be a requirement on sockets rated up to 32A rather than just 20A, there is an exception to omit RCD protection where, other than a dwelling, a documented risk assessment determines that RCD protection is not necessary.
RCD’s will also be needed on all AC final circuits supplying luminaires within residential buildings.
It is also important to note that Table 41.1 now applies to final circuits rated up to 63A (with sockets attached) so maximum disconnection times will apply to a greater number of circuits.
RCD’s should be tested every quarter and not 6 monthly.
Arc Fault Detection Devices (AFDDs)
AFDDs have been introduced in protection against thermal effects Chapter 42 as a recommendation of additional protection against fires that are caused by arc faults in AC final circuits. Arc fault detection devices (when used) should be installed at the origin of each final circuit that is are being protected.
In circumstances where over-voltage protection is not required, a risk assessment can be carried out. If a risk assessment is not carried out, over-voltage protection must be provided. Where there is risk of serious injury or of loss of life, where many co-located people are affected, where there is an interruption to public services, or commercial / industrial activity.
Metal Cable Supports
One of the big changes is wiring systems now must be supported against premature collapse in the event of fire and this applies throughout the entire installation by use of metallic clip supports. Not all clips will need to be metal, however – there just needs to be an adequate number in place e.g. every 4th clip.
These are just a few of the amendments that we have highlighted and there are many more.
For a full list read pages 4 – 7 of the BS7671 or CLICK HERE .