A tingle off the kitchen tap. A little bite from the washing machine when you lean on it with wet hands. A small shock from a light switch, or the feeling that every bit of metal in the house has it in for you. People often ring half-apologetic about this one - "it's probably nothing, it's only slight."

Stop there. A shock you can feel - however faint - means electricity is reaching metalwork it should never reach. That's not a quirk of an old house. That's a protection failure announcing itself, and it's the single symptom on this site where we'll tell you not to wait, not to watch it, not to see if it happens again.

What could be behind it

We diagnose on site, not from a description - but there are three realistic candidates, and two of them are serious:

A fault making exposed metalwork live because earthing or bonding is missing or inadequate. The classic version is a tingle from taps or pipework, and it's most common in older stock - the Victorian and Edwardian terraces and conversions all over West and North London are full of part-updated wiring where the earthing never caught up with the alterations. Proper earthing exists to carry fault current away and trip the protection instantly; if you can feel anything, that chain has a break in it somewhere.

A faulty appliance leaking current to its own casing is the other frequent find. The giveaway is that it's one appliance only - the machine bites, the taps don't.

Rarer, but real: a deteriorating supply neutral raising the earth potential. That's a network fault on the incoming supply rather than anything in your installation - less likely, but part of why proper testing matters rather than guessing.

Why this one is urgent

Because the maths is brutal. A perceptible tingle means the protection that should have cleared that fault has already failed somewhere. What you felt was the leak at its current size - and faults grow. The next one through the same broken chain could be full mains voltage through someone's hand.

And the risk isn't spread evenly. Children, older people, and anyone wet or barefoot - which in a kitchen or bathroom is everyone - take far more current from exactly the same fault. The tap that tingles against your dry palm is a different proposition against a child's wet one.

So the rule is short: this is an emergency, every time. Isolate and get help on the way. Never a wait-and-see symptom, never one for the weekend list.

What's safe to do right now

Stop using the appliance or fitting that bit you. If it's an appliance and you can unplug it dry-handed and safely, unplug it - then leave it alone.
If it's metalwork - taps, pipes, a sink, a radiator - switch the whole installation off at the main switch and make the call straight away. Don't go hunting for the cause yourself; the fault that makes a pipe live doesn't care how careful you are.
And look after the person before the property: anyone who's taken a significant shock - especially with burns, or a jolt across the chest - needs medical attention, not just an electrician.

That's it. This is the shortest safe-checks list we write, because with live metalwork there's no such thing as safe investigating.

Electrical safety certificate London checks we run

When the engineer arrives, the sequence is fixed. First, isolate and prove the affected equipment or circuit actually dead - proving dead is a test, not an assumption. Then we test the things a tingle calls into question: the earthing, the protective bonding to your pipework and services, and the earth fault loop impedance across the installation - in plain terms, whether a fault here can trip protection fast enough to matter. A suspect appliance gets tested separately from the fixed installation, so we know which side of the plug the problem lives on.

This is bread-and-butter landlord electrical safety territory too: broken earthing is exactly the kind of defect eicr testing London rentals go through every five years exists to catch, and it's a routine cause of an unsatisfactory result in older lets. Every engineer holds the qualifications required for the work - you'll get straight answers about what failed and why.

Making it safe, then fixing it

Two stages, in strict order. First, emergency attendance to isolate and make safe - a 24/7 emergency electrician call-out whose only job is to find the live metalwork and take the danger out of the building. Emergency electricians are available 24/7, year round, so "it's Sunday" is not a reason to live with a live tap.

Then the cure: bringing the earthing and bonding back to where they should be, so the protection chain works end to end - or condemning the faulty appliance if that's where the leak was. Either way we re-test afterwards, because "it's stopped tingling" isn't proof of anything. You get the results in writing, the same way an electrical installation condition report sets them out, so there's a record of what was wrong and evidence it's now right.

Don't test your luck twice

If anything in your home has made you flinch - tap, switch, machine, sink - flip the main switch off where it's safe to reach, and make the call now. Someone picks that phone up at any hour of the night. A tingle is the cheapest warning the electrics will ever give you; the follow-up fault doesn't always leave room to ring anyone.

Tingling or a shock from a tap, appliance or switch in London