No Power to Sockets? Systematic Troubleshooting Guide

1. Check the consumer unit. Open the cover and look for any tripped switches. If an MCB or RCD is in the down or middle position, that circuit has tripped. Try resetting it (push it firmly to the up position). If it holds, the problem may be resolved. If it trips immediately, leave it off and call an electrician.
2. Check whether other sockets in the property work. Test sockets in different rooms. If all sockets are dead, the RCD protecting the socket circuits may have tripped. If only sockets in one area are dead, the fault may be on one specific circuit.
3. Check the appliance, not the socket. Try plugging a known-working appliance (a lamp, a phone charger) into the suspect socket. If the appliance works, the problem was with the original appliance, not the socket.
4. Check for blown FCU fuses. If the dead socket is supplied via a fused connection unit (common for kitchen worktop sockets, extractor fans, and outdoor sockets), check whether the FCU fuse has blown. The FCU is the small rectangular unit with a fuse carrier on the front.
5. Check whether neighbours are affected. If all power is off (not just sockets), check whether your neighbours have power. If they do not, the problem is with the supply — contact your electricity supplier, not an electrician.

• Complete break: If the cable is completely severed (a nail through both conductors, a joint pulled apart), all sockets beyond the break — when measured from both directions around the ring — will lose power. The sockets before the break on each leg of the ring will continue to work.
• Single conductor break: If only the line conductor is broken (but the neutral and CPC are intact), the affected sockets will be dead. If only the neutral is broken, the sockets may appear dead or may behave erratically (depending on the load conditions on the circuit).
• CPC break only: If only the earth conductor (CPC) is broken, the sockets will still work (power is present) but the earth path is compromised. This is dangerous because the protective device cannot disconnect quickly enough in the event of an earth fault. An earth loop impedance test will reveal the high Zs.

Pass/fail criterion — GN3 Reg 2.20

When the CPC is the same cross-sectional area and material as the line conductor (standard 2.5/1.5 mm² twin-and-earth), the line-to-CPC resistance measured at each socket-outlet around the ring will be substantially the same — approximately one quarter of the total line-plus-CPC loop resistance. Readings that are substantially equal confirm acceptable ring continuity. A significant outlier (a reading materially higher than the others) at a particular socket indicates a high-resistance joint or partial break at or between that socket, and shall be investigated — it is not sufficient to confirm only that no socket reads open circuit.

• Line conductor loose at socket: If the line connection to the incoming cable is loose, that socket and all sockets downstream (on that leg of the ring) may lose power. If it is the outgoing cable that is loose, only downstream sockets are affected.
• Neutral conductor loose: A loose neutral at a socket can cause intermittent operation — the socket may work with light loads but fail under heavy loads when the higher current causes the loose connection to open.
• Junction box connections: Junction boxes under floors and in loft spaces can develop loose connections due to vibration, thermal cycling, and poor initial workmanship. A failed junction box connection has the same effect as a cable break at that point.
• Distribution board terminals: A loose connection at the MCB terminal will affect the entire circuit — all sockets on that circuit will be dead. Check both the line connection at the MCB and the neutral connection at the neutral bar.

Tools you will need

• Low-reading ohmmeter — a standard continuity buzzer is not sufficient for ring circuit continuity work; you need an instrument capable of resolving milliohm differences to detect high-resistance joints.
• Proving unit — used to confirm your voltage indicator is functioning correctly before and after proving dead (prove — test — prove sequence).
• Two-pole voltage indicator (GS38 compliant) — for proving the circuit dead before opening any socket faceplate.

1. Check the consumer unit. Is the MCB for the socket circuit in the on position? Is the RCD protecting that circuit in the on position? If either has tripped, investigate why before simply resetting.
2. Determine the scope. How many sockets are dead? Which rooms? Use a socket tester or voltage indicator to test multiple sockets. Map the dead sockets against the circuit chart (if one exists) to understand which circuit is affected.
3. Check for tripped FCUs. Walk around and check all fused connection units on the affected circuit. An FCU with a blown fuse will have no neon indicator (if fitted). Check the fuse with a continuity tester.
4. Perform safe isolation. Isolate the circuit at the consumer unit. Lock off and prove dead at the point of work.
5. Test the ring circuit continuity. At the distribution board, disconnect both ends of the ring. Test R1, Rn, and R2 end-to-end. An open circuit on any conductor confirms a broken ring.
6. Cross-connect and test at each socket. If the ring is broken, perform the cross-connected (figure-of-eight) test, measuring at each socket around the ring. The readings will be anomalous at the socket where the break occurs — this locates the fault.
7. Inspect connections. At the socket nearest to the identified fault location, open the faceplate and inspect the terminal connections. Look for loose conductors, evidence of arcing, heat damage, and pulled-out wires.
8. Test insulation resistance. Perform an insulation resistance test on the affected section to check for cable damage.

• Use a voltage indicator, not a neon screwdriver. A two-pole voltage indicator (GS38 compliant) is the only reliable way to test for the presence of voltage. Neon screwdrivers can give false readings and are not suitable for proving dead.
• Prove — test — prove. Before testing the dead socket, prove your voltage indicator on a known live source. Then test the dead socket. Then prove the indicator again on the known live source. This confirms the indicator was working correctly during the test.
• Lock off at the consumer unit. Switch off the MCB, apply a lock-off device, and attach a warning tag. This prevents anyone from re-energising the circuit while you are working on it.
• Beware of back-fed circuits. On a ring circuit, isolating the MCB disconnects the supply from the consumer unit, but if the ring has a connection to another circuit (a borrowed neutral, for example), there may still be voltage present. Always prove dead at the point of work, not just at the consumer unit.