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A Useful Guide When Purchasing Socket Testers

If you have a house or you are in the process of buying it, you may need to carry out a few tests around the house to ascertain whether all the systems are working. One of the systems that is crucial and whose functioning impacts virtually every aspect of the house is the electrical system. One of the electric system tests you must carry out is the determination of whether the sockets are working or not. Using the best socket tester, you can establish whether power is getting to the socket and that wires are connected to the right terminals.

Before we go into more details, here is a selection of top rated socket testers on the UK market:


Socket Testers



What Exactly is a Socket Tester?

A socket tester can best be defined as a portable electrical instrument that is used in testing power outlet sockets for correct operation and wiring standards. Typically, a socket tester is a hand-held instrument that comes with a short lead and plug or with pins mounted on it which plug directly into the socket.

Depending on how sophisticated the socket tester is, it may have a wide range of status indications including reversed phases, disconnected phases, and earth loop impedance. A majority of testers in the market display test results on a set of light-emitting diodes with others allowing you to carry out an earth leakage test from the push of a button.

In any home or commercial building, power outlet sockets are the majority of electrical devices. They form the first line of contact between you the consumer and the power grid. For this reason, their safe and correct operation is a critical consideration.

Ideally, tests should be done on a regular basis as opposed to one off. This is because the electrical system just like any other system may deteriorate in performance thus developing faults over time. Through a socket tester, you can speed up the testing task irrespective of the number of sockets and return more accurate and reliable information on the status of the sockets tested.

What to Look for When Buying a Socket Tester

Socket testers have largely been relied upon to demonstrate the safety of socket outlets. This could be as part of an initial verification of installed socket outlets or an ongoing, periodic testing of socket outlets. From the outset, it must be acknowledged that no socket tester can singlehandedly provide full safety assurance of your socket outlet (and often it’s better to call a professional electrician to do it for you). That said, there are certain factors which can guide into buying the best socket tester.

1. Type of Tester

As pointed out earlier, there are 3 types of testers: simple, advanced, and professional. The simple socket testers are designed to detect a number of electrical faults apart from earth fault loop impedance and other advanced faults.

On the other hand, the advanced and professional testers not only test a much wider range of faults, but measure how effective the protective earthing is as well. In their display, the advanced and professional testing devices will show either the numerical value of the loop impedance or the range of values within which the earth fault loop impedance lies.

2. Quality

When looking at the quality of socket testers, you need to check whether the testers can verify that the safety requirements of electrical installations as stipulated under the British Standard BS 7671 are met. One of the requirements is the adequacy of protective earthing in electrical installations. On the part of the devices themselves, they must meet the BS EN 61557-3:2007. This standard is for electrical safety of testing, measuring, and monitoring equipment used in low voltage distribution systems up to a maximum of 1000 volts AC and 1500 volts DC.

3. Functionality

The main reason why you are buying a socket outlet test device is to help you indicate whether the socket outlet is safe for use. This is why the functionality or capability of the socket tester must be above board. Check whether the tester can detect reversed line and neutral, reversed line and earth, as well as detect presence of earth. If you get a socket tester that can display the range of numerical values within which the earth fault loop impedance falls, it can be a real deal.

4. Price

Depending on the type of socket tester, design, and ease of use, you may get an array of devices you can choose from. Pricing is an important guide although it should never be the main deciding factor on whether to buy or not to buy. Simple testers are the cheapest and cost less than £20 while the professional ones, cost hundreds of pounds.

Main Brands

The following are the top brands in the DIY socket tester market.

  • Kewtech
  • Martindale
  • Socket & See
  • Fluke

1. Socket & See SOK36 Professional Socket Tester


The Socket & See brand is one of the prominent players in the socket tester market. With slightly under 20 years of active market innovation, Socket & See has a pool of professional and high-qualified treadspeople. Apart from being a professional socket tester, the SOK36 can be used for residual current device (RCD) testing, earth loop testing, and polarity testing.

Among the outstanding features of this tester model include:

  • Bright LEDs – This lighting is stronger and more vibrant than neon. It brings to your attention what the issue is in a more noticeable manner.
  • Logical Lighting – SOK36 uses the green lighting for the same universal purpose to indicate that all is well.
  • Indicative Tones – The device gives a continuous audible tone which means the wiring is good. However, when you hear a strong warbling tone, it is a clear indication that your wiring is faulty.
  • It indicates up to 18 wiring fault conditions.

In addition to the above, this socket tester can show you exactly where the actual fault is whether in earth, live, or neutral.

2. Martindale MAREZ150 Loop Check Plug Tester


The EZ150 is one of the best socket tester with the ability to check the wiring of 13 ampere sockets as well as give you an accurate measurement of earth loop impedance. It goes beyond what ordinary socket testers do to indicate how safe the connected earth is. Because of this, the EZ150 cannot pass as safe, a dangerously high earth resistance.

The outstanding features of this tester include:

  • Non-trip earth loop testing – Using this tester, you can quickly and conveniently evaluate an electrical circuit and measure its ability to engage protective devices.
  • Voltage test – Using a high voltage source, you can perform this test using the EZ150. The basic aim of this test is to monitor current leakage as the voltage to advise is enhanced.
  • Socket test – Using this tester, you can test for correct wires and open termination.

In addition to the above features, this tester employs the T-Safety technology which allows for safe checking of the earth loop impedance within selected bands without necessarily tripping the RCDs.

3. Kewtech LOOPCHECK107 Mains Socket Tester with Loop Check


This is an advanced socket tester which allows you to conduct a standard socket test that checks for the configuration of wiring at the socket, a loop testing to check for the presence of earth connection, as well as the quality of that connection. One other thing that the 107 does which few other socket testers do is a mains polarity check. This checks for polarity that is coming into the building.

Among other things, the Kewtech LOOPCHECK107 Mains Socket Tester:

  • Checks for the earth loop return path quality which is a plus for any tester.
  • Automatically runs checks for your wiring when you insert the device into the mains. It has both red and green LEDs.
  • Gives a continuous tone to indicate that the results are satisfactory. For faults, the device gives a warble tone.
  • Is much simpler to use because all you need is to plug it in and will immediately kick on to evaluate your wiring status.

The tester is designed to easily fit into the typical UK 3 pin plug sockets.

4. Fluke SM100 Socket Master Socket Tester


One unique advantage with Fluke devices is that they are available in a wide range, featuring modern, durable, and ergonomic designs. The SM100 is specifically designed with contractors in mind, to give them rapid and reliable testing devices with which to vet the safety of installed sockets.

In the SM100, Fluke built-in the following features:

  • Clear LED indication – Once you plug it in, the wiring status is brightly captured through the LED indicators.
  • Durable and compact – This tester is designed to meet the safety requirements stipulated under the BS EN 61010-1:2010 standard for electrical equipment used in control, measurement, and laboratories.
  • Modern ergonomic design – The soft finger grip is a unique design feature not found in many testers. This makes handling safer and more comfortable.

To add to the above features, this tester is much simpler to use because all you need to do is to plugin to your select socket and the results will be out almost instantly.

5. Martindale BZ101 (Buzz-It) 240V Socket Tester with Audible Buzzer


If you want a faster and simpler way to check whether your 13 ampere sockets are working correctly, the BZ101 is one of the best socket tester for the job. The LED indication this tester utilizes is similar to that of the CP501 save for the audible sounder which comes off to confirm the wiring is configured correctly. This is a unique advantage particularly when checking remote sockets or those installed in hard-to-see areas.

Some of the key features of BZ101 are:

  • Ability to detect up to 28 fault conditions.
  • Audible indication which can double up as a basic fuse finder. Whenever the correct fuse is pulled, the Buzz-It sounder goes silent.

It is also lighter in weight measuring just 60 grams. To assure you of quality, Martindale stands behind its brand to offer you a solid 2-year warranty.


  1. Ian Straub
  2. Ben Collins
  3. John Phelan

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