BS 7671 is non-statutory but the Electricity at Work Regulations 1989 (EAWR) are written into law.
The EAWR are general in their application and refer throughout to ‘danger’ and ‘injury’. Danger is defined as ‘risk of injury’ and ‘injury’ is defined in terms of certain classes of potential harm to persons. Injury is stated to mean death or injury to persons from:
- electric shock;
- electric burn;
- electrical explosion or arcing; or
- fire or explosion initiated by electrical energy.
Regulation 12(1)(b) of EAWR states ‘where necessary to prevent danger, suitable means shall be available for […] the isolation of any electrical equipment’, where ‘isolation’ means the disconnection and separation of the electrical equipment from every source in such a way that the disconnection and separation is secure.
The main requirements for isolation and switching are provided in Chapter 46 and Section 537 of BS 7671:2018+A2:2022.
Chapter 46 of BS 7671:2018+A2:2022 sets out the requirements for isolation and switching and Regulation 462.1 states that:
‘Each electrical installation shall have provisions for isolation from each supply.’
In my opinion the DNO/DSO/MO (Distribution Network Operator/Distribution System Operator/Meter Operator) in the UK should provide the isolator switch without question and possibly free or charge to comply with the Health and Safety act EWR 1989. Means for cutting off the supply and for isolation – It must be possible to switch off the electricity supply to any piece of equipment in case of electrical danger. This can be by direct manual operation, circuit breakers or by stop buttons in control circuits of contactors. Precautions for work on equipment made dead – Precautions must be taken to prevent electrical equipment which has been made dead (whether temporarily so work can be done or permanently because the equipment is no longer in use) from becoming charged during that work. If an Electrician has to change a CU/DB (Consumer Unit/Distribution Board) then an Isolator should be present as they are at work, thus the DNO/DSO/MO must provide it.
