BS 7671 (the IET Wiring Regulations) is the UK standard for electrical installation. Even if you're a mechanical engineer, you need to understand the basics — because your HVAC equipment needs power.
What BS 7671 covers that affects MEP
Cable sizing and voltage drop (Appendix 4) — Ensuring your motor or AHU gets enough voltage. Refer to the current edition for limits.
Protection against overcurrent — MCB/MCCB selection for MEP equipment.
Earthing and bonding — Particularly in wet environments (plant rooms, kitchens).
Special locations — Bathrooms (Part 7-701), swimming pools, medical locations.
Motor circuits — Starting current considerations, overload protection.
Current edition
18th Edition (2022), Amendment 2. Always verify against the current published edition for any project.
Key sections for mechanical engineers
Section 433 — Overload protection.
Section 525 — Voltage drop limits. Refer to the standard for current values.
Appendix 4 — Current-carrying capacity tables for cable sizing.