Electrical Troubleshooting Guide London — Free Advice | Olectrics Ltd

Question 1

Circuit breaker keeps tripping

Accepted Answer

A tripping breaker is your consumer unit protecting you from an overload or fault. Here's how to safely reset it and identify the cause. Turn off or unplug all appliances on the affected circuit before you do anything else. Open your consumer unit (fuse box) — usually found in a hallway, under the stairs, or in a cupboard. Look for the switch that has flipped to the middle or "off" position — it will be out of line with the others. Push the tripped switch firmly to the OFF position first, then back to ON. You should hear a click. If it trips again immediately, leave it off — there is a fault on the circuit. Call us. If it holds, plug your appliances back in one at a time. If it trips when you plug in a specific appliance, that appliance is faulty — stop using it.

Question 2

RCD keeps tripping

Accepted Answer

An RCD (Residual Current Device) is the wide switch in your consumer unit — it protects against electric shock. If it keeps tripping, follow these steps. Press the TEST button on the RCD — it should trip. This confirms it is working correctly. To reset: push the RCD switch firmly back to the ON position. If it trips again, unplug everything on the circuits it protects (sockets, lights, etc.). Reset the RCD again. If it holds with everything unplugged, plug items back in one at a time. The item that causes it to trip again is faulty — stop using it and have it checked. If the RCD trips with nothing connected, there is a wiring fault. Do not keep resetting it — call a qualified electrician.

Question 3

Changing a light bulb or lamp

Accepted Answer

Sounds simple, but there are a few important safety steps — especially with older fittings or recessed downlights. Turn the light switch OFF and wait at least 2 minutes for the bulb to cool down — halogen and older bulbs get very hot. For a standard bayonet cap (BC): push in gently, turn anti-clockwise and pull out. Insert the new bulb, push in, and turn clockwise until it clicks. For a screw cap (ES): turn anti-clockwise to remove, screw the new one in clockwise. For GU10 downlights: push up gently and turn anti-clockwise about 30 degrees, then pull down. Insert the new one, push up and turn clockwise. Always replace with the same wattage or lower — never exceed the fitting's maximum wattage (printed inside the shade or on the fitting). LED replacements are always a good swap — they run cooler, use less energy, and last far longer.

Question 4

No power to a socket or room

Accepted Answer

Lost power to one socket, a ring of sockets, or a whole room? Work through these checks before calling. Check your consumer unit — look for a tripped breaker or RCD (see guides above) and reset if needed. Check if neighbouring sockets work. If only one socket is dead, it may have a loose connection or be on a spur from another socket. Look for any fused spur switches nearby — a small switch with a fuse holder. Check the fuse inside hasn't blown. Check extension leads and plug-in adapters — these can fail and make it seem like the socket is dead. If a whole room has lost power and the breaker is on, there may be a loose connection in the circuit. Do not investigate inside sockets yourself. If you have a smart meter or recently had work done by your energy supplier, check the meter tails haven't been disturbed.

Question 5

Flickering or dimming lights

Accepted Answer

Occasional flicker is usually minor, but persistent flickering can indicate a wiring issue. Here's how to diagnose it. First, check if it's just one bulb — replace it. Loose bulbs in their fitting flicker. If you have a dimmer switch, check the bulb is dimmable. Standard LED bulbs on a dimmer will flicker — you need dimmable LED bulbs. If multiple lights flicker at the same time, especially when a large appliance (washing machine, kettle) switches on, this is a voltage fluctuation — worth reporting to your energy supplier. If lights flicker in one room only, there may be a loose connection in the circuit or at the light fitting. Persistent flickering across the whole house can indicate a problem with the main supply or meter tails — contact your energy supplier and an electrician.

Question 6

Air conditioning or heating not working

Accepted Answer

Before calling an engineer, run through these basic checks on your air conditioning or electric heating. Check the unit is switched on at the wall and the isolator switch (usually near the unit) is in the ON position. Check the consumer unit — air conditioning units are often on a dedicated breaker. Reset if tripped. Check the remote control batteries — a flat remote is a surprisingly common cause. Make sure the air filter is not blocked — a clogged filter causes the unit to shut down on thermal protection. Clean or replace it. For electric panel heaters: check the timer and thermostat settings haven't been accidentally changed. If the unit powers on but doesn't heat or cool, it may need a re-gas or service — call our F-Gas certified engineers.

Question 7

Full power cut — what to do

Accepted Answer

Lost all power to the property? Here's how to work out whether it's your property or a wider outage. Check if your neighbours have power — look for lights in nearby houses or ask. If they're also out, it's a network fault. Report a network outage to your Distribution Network Operator (DNO). In London this is UK Power Networks: 0800 028 0247. If neighbours have power but you don't, check your consumer unit for a tripped main switch or RCD. Check your electricity meter — if the display is blank and the meter is not a smart meter, the meter may have failed. Contact your energy supplier. If you have a prepayment meter, check your credit hasn't run out. If you've checked everything and still have no power, call us — it may be a fault on your meter tails or main fuse (DNO responsibility, but we can advise).

Electrical troubleshooting
you can do yourself

Circuit breaker keeps tripping

RCD keeps tripping

Changing a light bulb or lamp

No power to a socket or room

Flickering or dimming lights

Air conditioning or heating not working

Full power cut — what to do

When in doubt, call a qualified electrician

Electrical troubleshootingyou can do yourself

Circuit breaker keeps tripping

RCD keeps tripping

Changing a light bulb or lamp

No power to a socket or room

Flickering or dimming lights

Air conditioning or heating not working

Full power cut — what to do

When in doubt, call a qualified electrician

Electrical troubleshooting
you can do yourself