Why has my consumer unit tripped out completely and won't reset?

Why Has My Consumer Unit Tripped Out Completely? When your entire consumer unit goes dead — not just one circuit — it usually means the main switch (incomer) has tripped, or in older installations, the main fuse has blown. This is different from a single breaker tripping and is often a sign of a more serious electrical fault. What It Means The main switch is designed to protect your entire installation. If it trips, something has caused an abnormally high current or a fault that the individual circuit breakers couldn't handle on their own. It can also trip if there's a fault within the consumer unit itself, such as a faulty busbar or damaged wiring inside the unit. What You Can Safely Check Look at the main switch — is the toggle or rocker in the middle or fully down? This confirms it has tripped rather than been accidentally switched off. Switch off all individual MCBs and RCDs inside the unit before attempting a reset. Try resetting the main switch — push it firmly to OFF first, then back to ON. If it holds, turn circuits back on one at a time to identify the problem circuit. Check for obvious causes — did it trip during a storm (possible surge), after plugging in a new appliance, or during heavy rain (possible water ingress)? Check your electricity meter — if there's no display at all, the fault may be on the supplier's side. Contact your energy supplier. Warning Signs That Mean Call an Electrician Immediately The main switch won't stay on even with all circuits off You can smell burning from the consumer unit The consumer unit feels warm or hot to touch You can see scorch marks or melted plastic The unit buzzes, crackles, or sparks You have an older fuse board rather than a modern consumer unit When to Call an Electrician If resetting with all breakers off doesn't work, stop and call a qualified electrician immediately. A main switch that won't reset with no load connected almost certainly indicates a fault within the consumer unit itself — possibly a failed main switch, damaged busbars, or internal wiring failure. This is a C1 or C2 level danger and must not be left unattended.