Understanding how the regulations protect you from electric shock and fire — including RCDs, AFDDs, and why your fuse box matters more than you think.
When electricians talk about 'protection', they don't just mean fitting a fuse box. Under BS 7671, protection is a whole section of the regulations — Part 4 — dedicated to keeping people, property, and livestock safe from the hazards that electricity can cause.
Part 4 covers protection against electric shock, thermal effects such as heat causing burns or fire, overcurrent from too much current flowing through a circuit, and overvoltage from voltage spikes that can damage equipment or cause fires.
This is the big one. Electric shock can be fatal, and BS 7671 has two layers of protection: basic protection and fault protection.
Basic protection is about stopping you touching live parts in the first place — this is why cables have insulation, sockets have shutters, and consumer units have covers.
Fault protection kicks in if something goes wrong — for example, if a cable gets damaged and the metal casing of an appliance becomes live. This is where your RCD (Residual Current Device) comes in. An RCD detects tiny imbalances in current and trips the circuit within milliseconds — fast enough to save your life.
RCDs are one of the most important safety devices in a modern home. BS 7671 requires RCD protection for most circuits in a house, including sockets, lighting in certain locations, and any circuit supplying outdoor equipment. If your consumer unit doesn't have RCDs fitted, it's worth getting it looked at.
Electrical faults are one of the leading causes of house fires in the UK. Part 4 of BS 7671 deals with this through requirements around cable selection, overload protection, and AFDDs (Arc Fault Detection Devices) — newer devices that detect dangerous arcing in cables before a fire can start.
If your home was wired more than 10–15 years ago, it may not have all the protections required by the current edition of BS 7671. An EICR will assess your installation against current standards and highlight anything that needs attention. Contact Zeno Electrics for a free, no-obligation quote.