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A socket tester is the cheapest piece of test kit in an electrician’s bag and probably the most used. It plugs into a 13A socket, and a few lights tell you whether the wiring is correct, or whether you have a missing earth, reversed polarity or another fault. It takes seconds, which is why it gets used on every first visit, every quote and every quick check before a full test.
But not all socket testers are equal, and none of them replaces a proper test with a multifunction tester. We looked at what is available on Amazon UK, checked each model is in stock with a buy button, and picked six that cover different needs and budgets. Prices and review counts are as at the time of writing.
Quick Verdict
The Kewtech KEWCHECK103 is the best all-round socket tester for most electricians: a respected trade name, a simple display and more than 2,400 reviews. The Fluke ST240+ is the pick if you want an RCD test button and a name you can put in front of a customer. The Martindale EZ365 is the step up when you need non-trip earth loop impedance and RCD checks from the same plug-in unit.
If you just want something cheap to keep in the glovebox, the Kaiweets HT106E at under £12 has a good review record, though it is not a substitute for trade-brand test equipment.
Best Socket Testers at a Glance
| Tester | Price | Key features | Best for |
| Kewtech KEWCHECK103 | £22.00 | Mains wiring socket tester | All-round trade pick |
| Martindale CP501 Check Plug | £16.48 | Classic 240V check plug | Simple, rugged fault check |
| Martindale BZ101 Buzz-It | £17.34 | Audible buzzer | Noisy sites and quick checks |
| Fluke ST240+ | £39.15 | LEDs, RCD test button, beeper | Trade brand with RCD test |
| Martindale EZ365 | £74.79 | Earth loop, RCD, 28 fault conditions | Fuller plug-in testing |
| Kaiweets HT106E | £11.99 | LCD display, RCD test | Budget spare |
What to Look for in a Socket Tester
What a Socket Tester Can and Cannot Do
A basic plug-in tester shows wiring faults at the socket: open or reversed live, neutral and earth conditions. That is useful for a fast check. It does not measure earth fault loop impedance, insulation resistance or RCD trip time, and some faults can look correct on a basic unit. It is a screening tool, not a certificate. Anything that goes on an EICR or test certificate needs a proper multifunction tester.
Indicators: Lights, Buzzers and Displays
Most testers use a row of neon or LED lights with a fault chart printed on the case. Some add an audible buzzer for noisy sites, and some have an LCD that shows voltage or a fault code. A built-in fault chart is more useful than it sounds, because you will not remember every light combination.
RCD Test Button
An RCD test button lets you trip an RCD-protected circuit from the socket. It is a quick functional check rather than a trip-time test, but it is handy when you are checking a property and want to know the protection operates.
Build Quality
You will drop it, kick it and leave it on the van floor. Look for a solid case, firm pins and clear markings. Cheap units sometimes have loose pins that give poor contact and false readings.
The Best Socket Testers
Kewtech KEWCHECK103 Mains Wiring Socket Tester
Kewtech is a trade name that electricians know, and the KEWCHECK103 is its straightforward socket tester. At £22.00 at the time of writing it has more than 2,400 reviews, which makes it one of the best-reviewed in this guide. It tells you the state of the wiring at a glance, without bells or menus.
That simplicity is the appeal. You plug it in, read the lights against the chart and move on. For quotes, handovers and fault finding, it does the job without fuss.
Pros: Respected trade brand, simple to read, thousands of reviews, sensible price.
Cons: No RCD test button, and a basic indicator only.
Best for: Everyday electricians who want a reliable check plug.
- ✔️ SIMPLE TO USE: The Kewcheck 103 Socket Tester allows you to easily check if Live, Neutral and Earth wires are wired correctly on any UK plug socket. Simply plugs into the socket for results in seconds
- ✔️ DUAL RESPONSE: The LED lights integrated into this socket tester will then light up in a certain way depending on what's detected, and the product will either emit a continuous, warbling or no tone depending on what's detected
- ✔️ QUICK AND EASY: Designed to easily give quick and clear indication of the status of a socket's internal wiring without the need to remove the socket panel from the wall.
- ✔️ 14 WIRING CONDITIONS: All of the possible indications are displayed on the front of the Kewcheck103 to help with easily understanding the test results for each socket
- ✔️ BUY WITH CONFIDENCE: The Kewtech brand has become synonymous with high quality, as we manufacture innovative, accurate and reliable test equipment specifically for the UK market.
Martindale CP501 Classic Check Plug
The CP501 is the classic check plug from Martindale and costs £16.48 at the time of writing, with over 700 reviews. Martindale make test equipment for the trade, and the CP501 is a simple 240V socket tester designed to show wiring conditions at the socket.
Pros: Trade brand, low price, no-frills.
Cons: Basic indicator only, no RCD test.
Best for: A backup tester for the toolbox.
- Quick and easy testing of 240V UK sockets to ensure correct wiring and safety compliance
- Detects 28 common wiring fault conditions for reliable electrical safety checks
- Three bright LEDs with clear fault codes for instant and accurate identification
- Compact and tough design with sculpted grip for easy removal from sockets
- Ideal for electricians and homeowners for fast socket verification before use
Martindale BZ101 Buzz-It Socket Tester
The BZ101 adds an audible buzzer to the socket check. At £17.34 and with around 670 reviews, it is a useful variant if you work on noisy sites, or if you prefer a sound as well as a light when you plug in. Because the tester signals the result without needing you to look at it, it is quick when you are checking a row of sockets.
Pros: Audible buzzer, trade brand, inexpensive.
Cons: Basic checks only, no RCD test.
Best for: Checking lots of sockets quickly, in a busy or noisy environment.
- This is particularly useful when checking sockets that are not easily visible or in difficult to access locations
- With the audible indication, the Buzz-It can also be used as a basic fuse finder, when the correct fuse is pulled the buzzer stops
- Detects 28 fault conditions
Fluke ST240+ Socket Tester
Fluke is the name most customers recognise, and the ST240+ costs £39.15 at the time of writing. The listing describes LEDs, an RCD test button and a beeper, in the UK version. With 365 reviews it has a solid track record.
The RCD test button is the feature that sets it apart from the cheaper options here. If you want a branded tester that you are happy to pull out in front of a client, and that gives you a quick RCD functional check, it is a good buy.
Pros: Well-known brand, RCD test button, beeper and LEDs.
Cons: More expensive than other plug-in testers; still a basic check, not a full test.
Best for: Electricians who want RCD testing from a plug-in unit and a well-known brand.
- ST240+/UK, Socket Tester with LEDS, RCD TEST Button, Beeper, UK version
- Fluke ST240+ Socket Tester
- Package Dimensions: 28.0 L x 33.0 H x 35.0 W (centimeters)
- Item Package Weight: 1.0 kilograms
Martindale EZ365 Socket, Earth Loop and RCD Tester
This is the premium plug-in option, at £74.79 at the time of writing. The listing says it tests socket wiring, non-trip earth loop impedance and RCD function, detects 28 common wiring fault conditions with LEDs and a buzzer, and carries a fault chart on the tester. It also has an incoming supply polarity swap touch test.
It sits between a basic socket tester and a full multifunction tester. For quick-turnaround checks where you want to see earth loop and RCD results without setting up a multifunction tester, it adds a lot. It has fewer reviews than the cheaper models, which is typical for a more specialist product.
Pros: Earth loop and RCD functions, 28 fault conditions, fault chart on the case.
Cons: Expensive for a plug-in unit, and it does not replace a full multifunction tester for certification.
Best for: Electricians doing frequent quick checks on domestic sockets who want more than lights.
No products found.
Kaiweets HT106E Socket Tester
A budget option at £11.99, with more than 1,700 reviews. The listing describes an RCD plug socket tester with an LCD display. It is not a trade-brand test instrument, but as a spare in the van, or for an apprentice learning how to read fault conditions, it is a lot of tester for the money.
Pros: Very cheap, LCD display, RCD test function, large review count.
Cons: Not a recognised trade brand, and not for anything you will certify.
Best for: A spare tester or one for an apprentice.
- 【TESTING CAPABILITY】: This plug tester detects the most common wiring faults in standard and RCD electrical outlets, which is also with the standard uk and RCD protected 225 Volt AC Outlets. Capable of detecting the open wiring fault with open ground, open hot, open neutral, reverse polarity, hot/neutral reversed wires.
- 【RCD FUNCTION】: Simulating ground fault conditions, which works on RCD outlets and confirms operation of the ground fault protective device. It tests standard outlets that are wired in parallel to RCD outlets (multiple outlets in kitchen or bath, and outdoor receptacles require RCD protection). Be careful of using this function on normal receptacles. It may cause house wiring trip.
- 【VOLTAGE DISPLAY】: LED display helps you to measure the socket voltage and display it clearly in the LCD screen, it is also designed with a compact ergonomic and Hi-Impact Resistant ABS housing, which maintains an above industry standard impact & crush resistant rating.
- 【INSTANT WIRING IDENTIFICATION】: The Red LED indicators can be light up clearly for easy visual indication, when activated identify one of the seven common wiring options. An easy to understand chart on the tester helps determine wiring condition in outlet, based on LED lights results.
- 【SAFETY FIRST】: Conforms to CAT III 300V and CE-Marking, 7/24 lifetime technical support. Please feel free to contact us if you have any concerns.
Using a Socket Tester Safely
A tester only shows what it can detect. A correct indication does not guarantee a socket is safe, and you should never treat a socket tester as proof that a circuit is compliant. If a tester shows a fault, do not use the socket until it is investigated. Check the tester itself on a known good socket before relying on it, and replace it if the case is cracked or the pins are loose.
On site, a socket tester is also a handy way to confirm that a temporary supply or a distribution unit is wired correctly before you plug tools in.
FAQs
Is a socket tester the same as a multifunction tester?
No. A socket tester is a quick visual check of wiring at the socket. A multifunction tester measures values such as continuity, insulation resistance, earth fault loop impedance and RCD trip time, and is what you use for formal testing.
Can a socket tester detect everything?
No. It shows common wiring faults, but some conditions can give a misleading result, and it cannot measure the quality of the earth connection. Treat it as a first check.
Do I need a socket tester with an RCD test?
It is useful but not essential. The button gives a quick functional check on an RCD-protected socket. For trip times you need a multifunction tester.
Are cheap socket testers safe?
A cheap unit is fine for a quick indication so long as you understand its limits, but a trade-brand tester will be built to a higher standard. Never rely on a budget tester for anything you sign off.
How often should I check my socket tester?
Plug it into a socket you know to be correct before you start work, and look for damage to the case and pins. If it behaves oddly, replace it.
Final Thoughts
For most electricians the Kewtech KEWCHECK103 is the sensible default. Step up to the Fluke ST240+ for RCD checking or the Martindale EZ365 for earth loop as well, and keep a cheap Kaiweets in the glovebox as a spare. Whichever you choose, remember what a socket tester can and cannot tell you.
