BS 7671 Amendment 4: Timeline & Compliance Guide
15 April 2026
Publication
Amendment 4 published by IET and BSI. Available for purchase in print and digital formats. Voluntary adoption begins immediately.
April — October 2026
Transition Period
Six-month transition. Installations may comply with either the current standard (BS 7671:2018+A3:2022) or the new Amendment 4. Training providers begin delivering update courses.
15 October 2026
Mandatory Compliance
All new electrical installations and significant alterations should comply with BS 7671:2018+A4:2026. Certification bodies update their processes accordingly.
Before Publication (Now)
Review your current design practices and identify projects that may span the transition period. For projects starting before April 2026 but completing after October 2026, consider designing to anticipated Amendment 4 requirements where known. Attend industry briefings from the IET, NICEIC, or NAPIT to understand the scope of changes.
During the Transition
Purchase the amended standard and begin familiarisation. Complete any relevant update training. For new projects starting during the transition, consider adopting Amendment 4 immediately — it represents best practice and avoids the need to retrofit. Ensure your design tools and calculation software are updated to support the new requirements.
After the Transition
All new installations and significant alterations must comply with BS 7671:2018+A4:2026. Electrical installation certificates should reference the amended standard. Existing installations compliant with previous editions do not need retrospective upgrading unless alterations are made. Periodic inspection reports should note the edition of BS 7671 that was current when the installation was originally designed.
Certification & Registration
Competent person scheme providers (NICEIC, NAPIT, ELECSA, etc.) will update their assessment criteria during the transition period. Registered contractors should ensure they are assessed against the current standard requirements before the mandatory compliance date. Building control bodies will also update their procedures to reflect Amendment 4.