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Completing a project or building a product without actually testing it is definitely a recipe for a disaster. In almost all project development life cycles, testing is considered a very important phase at least before a product is released for use. The testing phase ensures that a product or a project meets the standards and requirements and is safe for use. In electrical engineering, electrical wiring is one of the projects where testing is critically important. Failure to test may result in damage of equipment, injuries, or even death. One of the areas where the test is normally conducted is on the power outlets. The test is performed using various tools, one of them being a socket tester.
What is a socket tester?
A socket tester is a plug-in electronic device designed to give a quick and easy indication of the condition of the socket outlet circuit. It is used by both skilled and unskilled persons to detect basic electrical faults on a standard wall socket as well as more modern outlets with USB ports. An outlet tester is also used to troubleshoot faults in an extension lead. Furthermore, vigilant home buyers use these socket testing devices to inspect the wall receptacles for safety and correctness of wiring before buying a house.
There are many proprietary socket testers in the market that vary in design and functionality. Based on their functionalities, receptacle testers are classified into three main categories: Simple, Advanced, and Professional. They are further classified according to the type of electrical outlet plug they are designed for. Globally, there are about 15 types of electrical socket plugs in use today. Each type is assigned a letter by the US Department of Commerce International Trade Administration from A to O. However, the most common power outlet standards in the market are the UK and US standards, which are types A&B and type G respectively.
Types of Power Socket Outlets and Plugs by Country Standard
1. US Power Socket (Types A and B)
Features of Type A power plug and socket
- Class II ungrounded plug
- Plug 2 flat parallel prongs.
- Prongs are polarised
- Plugs are polarised and can only be inserted one way.
- Rated 100V – 127V
- A socket has only two flat slots.
- Common standard in North and Central America
Features of Type B power plug and socket
- Class I grounded plug
- Plug 2 flat parallel prongs and a round or U-shaped earth pin.
- Earth pin is longer than the flat pins
- Plugs are polarised and can only be inserted one way.
- A socket has two flat slots and a round slot.
- For 100V – 127V ~AC
- Designated American standard.
2. UK Power outlet (Type G)
Features of Type G power socket and plug
- Plug has 3 rectangular prongs that form an isosceles triangle.
- Plug fitted with a 13A fuse.
- Receptacle has three rectangular holes
- For 220V – 240V ~AC
This article is a detailed review of the best UK and US socket testers. I have categorized them based on complexity of their features and the country socket standards.
| Features | Editor's Ratings | |||
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4 Best Simple U.S Standard Socket Tester |
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| Gardner Bender GRT-3500 Outlet Receptacle Tester |  
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Buy from Amazon | |
| Amprobe ST-101B Socket Tester |  
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Pros Cheap and easy to use Easy to read key Cons Incandescent lights are inferior to LEDs Vertical prongs makes reading key from a distance difficult |
Buy from Amazon | |
| Power Gear 3-wire Receptacle Tester |  
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Pros Cheap and easy to use Performs basic tests Cons Vertical prongs makes reading key from a distance difficult Plastic case would break after a few drops People with difficulty in seeing might not differentiate yellow and white on the lables |
Buy from Amazon | |
| Electrical Receptacle Wall Plug AC Outlet Ground Tester with GFI Reset |  
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Pros Cheap and easy to use Performs basic tests Tests the GFI reset buttons Cons Plastic case would break after a few drops Relatively poor construction quality The labels are not firmly attached and thus may fall off |
Buy from Amazon | |
4 Best Simple UK Standard Socket Testers |
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| Kewtech KEWCHECK103 Mains Wiring Socket Tester |  
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Buy from Amazon UK | |
| ShoppingCentre Mains Socket Tester |  
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Buy from Amazon UK | |
| Martindale CP501 Socket Tester |  
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Buy from Amazon UK | |
| Invero® UK Mains Electrical Power Plug-In Socket Tester |  
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Buy from Amazon UK | |
4 Best Advanced US Standard Socket Testers |
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| Sperry Instruments GFI6302 GFCI Outlet Tester |  
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Buy from Amazon | |
| Meterk GFCI Electric Socket Tester |  
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Buy from Amazon | |
| Amprobe ST-102B Socket Tester with GFCI |  
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Buy from Amazon | |
| Tacklife EST01 Advanced GFCI Outlet Tester Power Socket |  
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Buy from Amazon | |
4 Best Advanced U.K Standard Socket Tester |
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| Kewtech LOOPCHECK107 Mains Socket Tester with Loop Check |  
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Buy from Amazon UK | |
| Socket & See SOK36 Professional Socket Tester |  
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Buy from Amazon UK | |
| Martindale MAREZ150 Loop Check Plug tester-Yellow |  
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Buy from Amazon UK | |
| Socket Tester, Tacklife EST03 Advanced GFCI Power Meter 220-250V Mains Outlet Live Neutral Earth Wire RCD Tester |  
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Buy from Amazon UK | |
Socket Tester Reviews by Functionality
As mentioned earlier in this article, socket testers are classified into three functional categories: simple, advanced, and professional. In the next few sections, we shall be exploring the features of each type as well as reviewing some of the best devices on the market.
Simple Socket Testers
A simple socket-outlet tester is a device designed to detect some of the basic electrical faults that might occur in the power outlet wiring. It is also considered as a tool for the first-line diagnosis of a power outlet wiring. Most simple socket testers have three LEDs to indicate the state of a socket wiring, and a reference menu to interpret the LEDs sequence. It can be used by skilled or unskilled persons to detect faulty wiring in a wall socket or an extension lead. However, the downside is that a simple outlet tester detects the absence of an earth fault but cannot measure the actual earth fault loop impedance at the socket outlet.
Advanced Socket Testers
An advanced socket tester is designed to detect a wide range of faults including what a simple socket tester detects. In other words, you can use an advanced receptacle tester is to test the wiring of a wall socket and to carry more advanced tests such as earth loop impedance, RCD test. Some advanced outlet testers even perform a polarity check.Earth loop impedance simply refers to the measure of the effectiveness of the protective earthing. An advanced socket-outlet tester displays either a range of numerical values into which the earth fault loop impedance falls. An electrician then interprets the range to determine if the outlet socket is grounded for safety. RCD check involves testing the functionality of an RCD installed on the premises. It sends a tripping current to safely trip an RCD in order to ensure that it will operate as required should there be an accident. For the US standard sockets, the RCD test current is 5mA and 30mA for the UK sockets. The polarity check feature allows you to check the possibility of a neutral/live(hot) swap at the mains supply – where the supply enters the premises. An advanced socket tester is meant to be used by a skilled electrician who can interpret the outcomes of each test.
Sperry Instruments GFI6302 GFCI Outlet Tester
If you are looking for an outlet tester that combines a unique compact ergonomic design with both basic and advanced features, then look no further than the Sperry Instruments GFCI6320 outlet tester. It is a little handy advanced socket tester designed to test for 7 different wiring conditions. It also has a GFCI button for testing GFCI protected outlets. The tool is designed with the user’s safety in mind because its sturdy plastic casing offers double insulation that adds a layer of protection to the user.
The sperry instruments GFI6302 receptacle tester also provides comfort to the user with its rubber over-moulded grips. The socket tester is also made of tough and durable material that makes it ideal for use in any environment with CAT III 300V rating. In fact, the unit is cULus listed, meaning that it has been tested to meet the US and Canadian requirements. It is also CE approved which simply means that the unit meets the EU health, safety and environmental requirements that ensure consumer and workplace safety.
Advantages
- The wiring legend printed in both sides makes ideal for use on upright and inverted sockets
- The rubber over-molded grips offer a comfortable grip
- It is durable and reliable
- Ideal for testing exterior outlets with covers
- Has a limited lifetime warranty
DIsadvantages
- The test button is so sensitive that the slightest stroke will cause it to test the GFCI
- The incandescent notification lights are hard to tell if they are on in a well-lit room
- Only has visual indicators
- Contains a chemical known to the state of California to cause cancer and birth defects or other reproductive harm.
- Will not detect 2 hot wires in circuit
Meterk GFCI MK16US Electric Socket Tester
If you like installing your wall socket upside down then the Meterk GFCI socket tester is the tool for you. It is built nicely with strong, stiff, impact-resistant, and flame retardant ABS material for durability and versatility. The unit is ideal for checking the wiring in the house and the polarity of the socket connection. Meterk GFCI receptacle tester, like the other advanced socket testers, has a GFCI button for tripping the GFI electrical sockets. It also features three bright LEDs for indicating 7 possible wiring statuses of a socket. The front has a graphic to explain the LED patterns.
Advantages
- Has 3 Bright LEDs are visible in a lit room
- The case has a reverse taper that makes this tool easier to plug in and out
- The front of unit has a graphic to explain the LEDs patterns
Disadvantages
- User manual is not easy to read
- Will not detect 2 hot wires in circuit
Amprobe ST-102B Receptacle Tester with GFCI
The armprobe ST-102B socket tester is red in color with a black GFCI test button for testing the GFCI sockets. It has three vertical US standard prongs on one end and three incandescent lamps on the other. The unit also has a legend that explains six wiring conditions. Regarding user’s safety, the armprobe ST-102B socket tester is listed for safety by UL and cULus safety agencies and is designed to test 110 to 125V AC outlets.
Advantages
- Meets safety regulations
- Has a manual written in English and Spanish
- Engineered to perform in a tough and professional environment
Disadvantages
- User manual is not easy to read
- The incandescent lights makes it difficult to tell if the light are on in a well lit room
- Only has visual indicators
- Will not indicate quality of ground resistance
- Will not detect 2 hot wires in circuit
- Will not detect a combination of defects
- Will not indicate reversal of grounded and grounding conductors
Tacklife EST01 Advanced GFCI Outlet Tester Power
In case you are searching for versatile advanced socket tester that combines horizontal prongs and LEDs instead of incandescent lights, then the Tacklife EST01 Advanced GFCI Outlet Tester is what you need. The unit has two green LEDs and a red LED which indicate 7 different wiring statuses of your power receptacle. It also has an easy to read faults chart printed on the front that explains the seven possible LEDs patterns which include correct wiring, hot neutral reverse, hot ground reverse, missing neutral, missing hot, and missing ground.
Like the Sperry GFCI6320 tester, Tacklife EST01 features a GFCI test button that sends a 5mA tripping current to the GFCI socket to ensure electrical safety. The contrast, however, is that unlike the Sperry instruments unit that has a lifetime warranty, this unit only has 2 years of cover. Tacklife EST01 is CE rated and approved for use in CAT. II 600V rated environments such as schools, laboratories, and other social fields.
Advantages
- 3 Bright LEDs that can be seen well in both a dark and a lit room
- Has a 2 year warranty cover
Disadvantages
- Not ideal for wall sockets with a ground at the bottom
- Only has visual indicators
- Its square shape makes it hard to test exterior outlets with exterior covers.
- The ground prong tends to come lose when a lot of force is used to push it into a socket outlet
- Will not detect 2 hot wires in circuit
4 Best Advanced UK Standard Socket Testers
Professional Socket Testers
This socket outlet test device is more complex than advanced devices because it uses additional components and technology to indicate loop impedance more accurately; either in numerical values or shorter ranges. It has all the normal checks of an advanced socket tester. The device conforms to the BS EN 61557-3 standards and therefore it can be used to certify or report on an electrical installation. Similar to the advanced device, a professional tester is also meant to be used by skilled technician.
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If you have a second… I wanted to ask you something though… Do you have an opinion on Milwaukee power tools? I just bought a house and I’m starting to collect some tools. Eagerly awaiting your reply. 🙂
Generally, Milwaukee has some of the most reliable tools in the market. You can check out how they compare with other tools in the reviews here