A Step By Step Guide

A tripping RCD will come at the most inconvenient time and usually when you just don't need it! Sometimes it can be a very basic fix where as other times it will need a qualified Electrician with the correct test equipment to fault find.  Below is a 'first steps guide' that could save you the cost of calling out an Electrician for what could be a simple fix.  If you try all of this and it still does not reset then its at that point you will need more experts eyes.  I hope this works for you and saves you some wonga !

Make sure you have a torch or similar to ensure you have maximum visibly when doing this.

To fault find a tripping RCD step-by-step, first turn off all circuit breakers (MCBs), reset the RCD, then turn MCBs back on one by one to find the faulty circuit (when it trips, you've found it). Next, unplug all appliances on that circuit and plug them back in one by one, resetting the MCB each time, to find the specific faulty appliance (the one that causes the trip). If the RCD still trips with everything unplugged, the fault is likely in the wiring or a fixed appliance (like a heater) and requires a professional electrician. 

Step 1: Initial Reset & Isolation

1. Ensure safety: Make sure your hands are dry and you're not standing in water.
2. Turn off all MCBs: Go to your consumer unit (fuse box) and switch all individual circuit breakers (MCBs) to the 'OFF' position.
3. Reset the RCD: Toggle the RCD switch to 'OFF' and then back to 'ON' (you might need to press down firmly).
4. If it holds: The fault might have been temporary. If it trips immediately, proceed to Step 2. 

Step 2: Find the Faulty Circuit (MCB)

1. Turn MCBs on one by one: Turn on each MCB one at a time, waiting to see if the RCD trips.
2. Identify the circuit: The MCB that causes the RCD to trip again is protecting the faulty circuit.
3. Leave it off: Leave that faulty circuit's MCB in the 'OFF' position to restore power to the rest of your home

Step 4: Address the Fault

• Appliance fault: The faulty appliance can be repaired or replaced.
• Wiring/Fixed Appliance fault: If the RCD still trips with everything unplugged (including fixed items like immersion heaters, ovens, or extractor fans), the problem is likely a wiring fault (damaged cable, loose connection) or a fault within a fixed device.
• Call a Professional (Me😀) : If you've unplugged everything and the RCD still trips, call a qualified electrician to diagnose and fix the underlying wiring or installation fault.