Stop, isolate, call
Three situations where nothing else on this page matters.
Burning smell or scorch marks
A hot plastic smell, browning around a socket, or marks on the consumer unit. Stop using the circuit, switch it off at the board if you can do so safely, and call.
Water near electrics
A leak reaching a consumer unit, light fitting or socket. Do not touch anything wet and never reach for the board through water. Keep everyone clear and call from another room.
A shock, buzzing or crackling
Anyone who has had a shock off an appliance or switch should stop using it. Buzzing, crackling or a warm socket means the circuit needs isolating.
Is it everything, or one circuit?
This is the first thing we will ask, and it changes who you need.
Everything is off
Look at the consumer unit. If the main switch or an RCD has gone down, the fault is inside the property and it is one for us.
If the board looks untouched, check whether your neighbours have power. If the street is dark, the supply has failed and no electrician can restore it.
One circuit is off
One breaker down and the rest of the board normal usually means a fault on that circuit, often a failing appliance rather than the wiring.
A circuit that keeps tripping still needs testing. Forcing it back on is not a fix.
What an RCD trip actually means
An RCD compares the current going out to a circuit with the current coming back. When they stop matching, some of it is leaking where it should not, and the RCD cuts the power in a fraction of a second.
That is the device working, not failing. The usual causes are a faulty appliance, water in an outside socket, or damp reaching a cable — which is why a washing machine can take the lights out with it.
Resetting it safely
- 1. Unplug everything on the affected circuit before you touch the board.
- 2. Push the switch firmly back up. Dry hands, dry floor, nothing wet nearby.
- 3. Plug things back in one at a time. The one that trips it is your culprit.
- 4. If it will not reset with everything unplugged, stop there and call us.
What to check before you call
Two minutes of looking saves guessing on the phone.
- Look at the consumer unit: one switch down, or the main switch?
- Ask a neighbour whether they have power, or check the street lights
- Check the meter, and the credit on it if it is prepayment
- Note which rooms and sockets are affected
- Think about what changed: a new appliance, a leak, work nearby
If the supply has failed, call 105
105 is the free national power cut line, covering England, Wales and Scotland. It is not us and not your energy supplier: it connects you to the network operator for your area, who is the only one able to restore a failed supply.
Use it when the street is dark. If only your property is off, the fault is inside it, and that is ours.
What we do when we arrive
- Make anything dangerous safe first
- Isolate the affected circuit rather than the whole property
- Test to find the actual fault, not the room it showed up in
- Tell you what we found and what putting it right takes
- Give you the price before the repair starts
- Repair it on the visit where parts allow, or make safe and return
- Test the circuit again, and certify the work where it needs it
For work that is not urgent, see our London electricians or book an EICR.
Being straight about availability
Plenty of London sites promise an electrician at the door within the hour, day or night. We will not, because we could not always do it.
What we do have is priority booking through membership: next day on Bronze and Silver, same day on Gold and Platinum, morning and late slots held back for members, a two-hour arrival window, and no call-out fee on any plan.
Not a member? Call anyway. We will say what we can realistically do, and what to switch off meanwhile.
NAPIT registered
Number 64777, fully insured including public liability.
Inside the M25 and just outside
One number for all of London.
Priority booking for members
Next day on Bronze and Silver, same day on Gold and Platinum, with morning and late slots held back for members and a two-hour arrival window.
Questions people ask with the lights off
Are you available 24 hours a day?
Not around the clock. We work six days a week, and we would rather say so than leave you waiting. Call 020 4634 2681 and we will tell you what we can do and when. Members get priority booking: next day on Bronze and Silver, same day on Gold and Platinum, with morning and late slots held back for members and a two-hour arrival window.
The whole flat has no power. What now?
Check the consumer unit first. If the main switch or an RCD has tripped, the fault is inside the property. If the board looks normal and your neighbours are dark too, it is a supply problem.
Only one circuit is dead. Is that less serious?
Usually, yes. One breaker down means the protection did its job and the rest of the property is unaffected. It still needs finding, because a circuit that keeps tripping is telling you something.
How do I reset a tripped RCD safely?
Unplug everything on the affected circuit, then push the switch firmly back up. Plug appliances in one at a time to see which trips it. If it will not reset with everything unplugged, stop and call us.
Is it safe to keep resetting it?
No. Once or twice to identify a faulty appliance is reasonable. Repeatedly forcing a breaker back on is not: it trips for a reason, and you are overriding the protection.
There is water coming through near a light fitting.
Treat it as live. Do not touch the fitting or the switch, and keep people out of the room. If you can reach the consumer unit without going through water, switch off the lighting circuit, then call.
What does an emergency visit cost?
The same rates as any other visit: from £75 an hour for Gold and Platinum members and from £80 for Bronze and Silver, against our standard rate of £120. No plan carries a call-out fee.
Which parts of London do you cover?
Everywhere inside the M25 and just outside it, north and south of the river. If you are not sure, call 020 4634 2681.
105 is a free public service run by the Energy Networks Association, not by Hem London, last checked on 12 September 2026. This page is general guidance, not an instruction to work on your own electrics. If you are not sure something is safe, leave it alone and call us.