How to test a flat's sockets yourself before you move in

What you need before you start

The main tool is a plug-in socket tester, sold cheaply in any hardware shop or online. It plugs straight into a socket and reads out wiring faults through a pattern of lights, with a legend printed on the body or in the box. Buy one before moving day; it's a five-euro item that pays for itself the first time it finds a problem.

Alongside the tester, have a torch, a small lamp or phone charger you know works, and a notepad or your phone's notes app to log which sockets and switches you've checked. A floor plan of the flat, even hand-drawn, helps you keep track of which room you're in when you write things up later.

Do the check in daylight if you can, room by room, with nothing plugged into the sockets you're testing yet. If the flat is still empty, this is the easiest time you'll ever have to do it properly.

How to work through the sockets with a tester

Plug the tester into every socket in the flat, not just the ones you expect to use. Kitchens, hallways, balconies and storage rooms get skipped most often and are exactly where older or botched wiring tends to hide. Note the reading for each one against your floor plan.

A correct reading usually shows as all the lights indicating normal wiring, but the exact pattern depends on the tester, so keep the leaflet handy the first few times. Common faults it will catch are no earth connection, earth and neutral reversed, or a missing neutral — all of which the tester will name or code clearly.

Push firmly and check the plug sits snugly; a socket that feels loose or lets the tester wobble is worn out even if the reading comes back fine. In older Tallinn buildings you may also find sockets with no earth pin at all, which was normal when the wiring was installed decades ago but is worth flagging rather than ignoring.

• Test every socket in every room, including hallway, balcony and storage
• Check the plug sits firmly, without wobble or looseness
• Log each result against a floor plan so nothing gets missed
• Note any socket with no earth pin, especially in pre-1990s buildings
• Pay particular attention to kitchen and bathroom sockets

What to check at the switches and light fittings

Go through every light switch and see that it does what it should: turns the right light on and off, doesn't flicker, and doesn't need a wiggle to work. A switch that needs coaxing is a sign of a loose connection behind the wall plate, not something to live with.

Flip switches on and off a few times and listen for buzzing or crackling from the wall or the fitting itself. If a light dims or flickers when another appliance switches on nearby, note it: it can point to a loose neutral connection somewhere on that circuit.

Check any switch plate feels warm to the touch after the light has been on for a while, and check that dimmer switches, if fitted, run smoothly through their range without stalling or flickering at one end.

How to spot sockets and plates that are running warm

After you've plugged something into a socket and it's been drawing power for ten or fifteen minutes — a kettle, a heater, a phone charger left running — touch the plate lightly with the back of your hand. It should feel roughly at room temperature, not noticeably warm.

A plate that's warm, or a plug that feels hot where it meets the socket, points to a poor connection inside: a loose terminal screw, worn contacts, or wiring that's undersized for what's being plugged in. This is one of the more reliable early signs of a fault, because it shows up under real load rather than on a tester's static reading.

Check this on sockets you expect to use for kettles, washing machines, ovens and heaters first, since those draw the most current and will show a problem fastest. A socket that's warm under light load, such as a phone charger, is a more serious sign than one that's warm under a kettle.

The most common mistake new owners make

The mistake we see most often is people testing the sockets they'll actually use — living room, bedroom — and skipping the rest because the flat looks fine and moving day is busy. Faults tend to cluster in the sockets nobody touches: behind where a fridge will go, in a hallway, on a balcony, in a store room off the kitchen.

The second version of the same mistake is testing once, on the day of moving in, and never again. A tester takes twenty minutes; running it again a few weeks in, once furniture has moved and appliances are in daily use, catches problems that only show up under real load.

When to stop testing yourself and call an electrician

A tester will tell you that something is wrong, but not why, and it isn't safe or useful to start opening socket plates or fiddling with wiring yourself. If any socket shows a fault reading, feels warm under load, or a switch buzzes, crackles or needs coaxing, that's the point to stop and call someone qualified.

We do electrical work from 49 € per hour, and a call-out to check a handful of flagged sockets and switches is usually a short, straightforward job. If the tester or your own check has turned up more sockets than you'd like, or you simply want an extra one added somewhere convenient, socket installation starts from 35 € per job.

If you're renting, it's worth raising anything you find with the landlord in writing before you start using the flat normally, both for your own safety and so there's a record of the flat's condition when you moved in.