16 Best Socket Tester Units for Testing Power Socket Outlets

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Completing an electrical wiring project without testing the correctness of the wiring is a recipe for disaster. If some wires are connected incorrectly, especially on socket outlets, they could result in equipment damage, injuries, or even death.

One of the simplest ways to check if a wall socket is wired properly is with a socket tester. You don’t need to be an electrician to use it.

In fact, a receptacle tester is one of those small tools a homeowner must have for troubleshooting electrical faults on receptacles before inviting an electrician.

What is a socket tester?

A socket tester is a plug-in diagnostic device for checking if the wall socket outlet is wired correctly. It is used by both skilled and unskilled persons to detect basic electrical faults on a standard wall socket as well as modern outlets with USB ports.

You can also use an outlet tester to check if an extension lead has any faults before connecting an appliance.

Other people who use receptacle testers quite often are vigilant home buyers. They use them to check whether the wall receptacles of the new home are correctly wired. This is a good inspection activity before buying a house that can help you avoid extra costs.

As you probably know, fixing wiring issues can be troublesome and costly. You dont want to incur that cost on a new house if you can avoid it.

Types of Power Socket Outlets and Plugs by Country Standard

There are many types and models of socket testers in the market which 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 for which they are designed.

Globally, there are about 15 types of electrical socket plugs. Each type is assigned a letter from A to O by the US Department of Commerce International Trade Administration. However, types A&B and type G electrical sockets are the most common power outlet standards in the market. They correspond to UK and US standards, respectively.

Common types of electrical outlets

1. Types A and B – US power sockets

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. Type G – UK Power outlet

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
• For UK

In this article, I have reviewed some of the best UK and US socket testers. I have categorized them based on the complexity of their features and the country socket standards.

Best Socket Testers for US and UK Standards

		Features	Editor's Ratings
4 Best Simple U.S Standard Socket Tester
Gardner Bender GRT-3500 Outlet Receptacle Tester		Works with US standard110-125V 60Hz 3-prong socket outlet Has three lamps (2 neon and 1 red) to indicate the staus of the power socket Dual status chart for multiple position viewing Compact and ergonomically shaped Has a housing guaranteed to withstand up to 10ft drop		Buy from Amazon
Amprobe ST-101B Socket Tester		Checks and confirms proper wiring of AC outlets Has three incandescent lights Operates on US standard AC socket outlets 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		Checks and confirms proper wiring of AC outlets Easy to read lights Operates on US standard AC socket outlets 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		Works with any 110-125V 60Hz 3-prong outlet Has three LEDs to indicate the staus of the wall socket Operates on US standard AC socket outlets Has labels on the front side to explain the status of the LEDs status Has a GFCI reset button 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
Kewtech KEWCHECK103 Mains Wiring Socket Tester		Has 6 LED patterns to indicate the status of the electrical socket. Has continuous audio tone for correct wiring Has a warble tone for incorrect wiring Plug has three rectangular prongs Suitable for 13A rated UK mains socket		Buy from Amazon UK
ShoppingCentre Mains Socket Tester		Has 5 LED patterns to indicate the status of the electrical socket. Has audio tone for LED statuses Plug has three rectangular prongs Suitable for 13A rated UK mains socket		Buy from Amazon UK
Martindale CP501 Socket Tester		Has 3 LEDs and 5 LED patterns. The top cover has simple fault codes Plug has three rectangular prongs Suitable for 13A rated UK mains socket Does not have audio indicators		Buy from Amazon UK
Invero® UK Mains Electrical Power Plug-In Socket Tester		Has 3 LEDs and 6 LED patterns. Complies with British Standard BS EN 610101-1 The top cover has simple fault codes Plug has three rectangular prongs Suitable for 13A rated UK mains socket		Buy from Amazon UK
4 Best Advanced US Standard Socket Testers
Sperry Instruments GFI6302 GFCI Outlet Tester		Has three neon lamps Indicates 7 common wiring conditions Has a legend on both sides indicating the light patterns and wiring conditions Has a GFCI test button for testing GFCI outlets It is compact and ergonomically designed with over-moulded rubber grips Tests US standard 3-wire and GFCI protected 120V outlets cULus and CE approved Lifetime warranty cover		Buy from Amazon
Meterk GFCI Electric Socket Tester		Has a US standard 3-pin plug Has a GFI test button Has a 3 LEDs to indicate the socket status Has 7 LED patterns to indicate the status of the electrical socket. Works with any 110-125V 60Hz 3-prong electrical receptacle		Buy from Amazon
Amprobe ST-102B Socket Tester with GFCI		Has a GFCI button Has an easy to read Has three incandescent lamps; 1 red and 2 amber Designed to test 110 – 125 V AC sockets Wattage rating: 0.3W Has a 90 days warranty		Buy from Amazon
Tacklife EST01 Advanced GFCI Outlet Tester Power Socket		Has three bright LED lights Has a GFCI test button Generates 5mA RCD test current Has a US standard plug 24 months warranty		Buy from Amazon
4 Best Advanced U.K Standard Socket Tester
Kewtech LOOPCHECK107 Mains Socket Tester with Loop Check		Automatically runs a wiring check when plugged into a receptacle Features three bright LED lights to show different wiring conditions Includes a continuous tone for good wiring and a warble for bad wiring Has an RCD test button that causes the tester to generate 30mA RCD test current Also features an array of color LEDs to indicate the quality of the earth path Highlights faults by red and orange LEDs and a warble tone		Buy from Amazon UK
Socket & See SOK36 Professional Socket Tester		Has a self-checking mechanism when plugged into a socket Features three bright LEDs to show the wiring status Also features an RCD test button that sends 30mA residue current Includes a polarity check feature for detecting possible L-N swap at the mains supply Includes an array for LEDs to display the value range of loop impedance It is small and compact		Buy from Amazon UK
Martindale MAREZ150 Loop Check Plug tester-Yellow		Has three LEDs to indicate various wiring conditions Also features three more LEDs for indicating the earth fault loop impedance. Performs voltage test(high, low, and normal) Does not include RCD functionality check		Buy from Amazon UK
Socket Tester, Tacklife EST03 Advanced GFCI Power Meter 220-250V Mains Outlet Live Neutral Earth Wire RCD Tester		Features three bright LED lights to show 7 different wiring conditions Also features an RCD test button Generates 30mA RCD test current Compliant with CE CAT.II 600V RoHS safety standard 24 months warranty		Buy from Amazon UK

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 explore some of the best socket testers in each category in the UK and US markets.

Simple Socket Testers

A simple socket-outlet tester is a device designed to detect the most basic electrical faults that can occur in the power outlet wiring. It is also considered a first-line diagnostic tool for power outlets.

Most simple socket testers have three LEDs to indicate the state of a socket wiring, and a reference menu to interpret the LEDs sequence. They can be used by skilled or non-skilled persons to detect faulty wiring in a wall socket or an extension lead.

The downside of a simple outlet tester is that it can detect 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 everything that a simple socket tester detects. You can use it to test the wiring of a wall socket and to carry out more advanced tests such as earth loop impedance and RCD/GFCI test.

Some advanced outlet testers can also perform a polarity check.

What is earth loop impedance?

Earth loop impedance is the measure of the effectiveness of the protective earthing on a socket. An advanced socket-outlet tester displays a numerical value or range within which the earth fault loop impedance falls.

Only a skilled electrician can interpret earth loop impedance readings to tell if the electrical socket is safely grounded.

What is RCD or GFCI test?

RCD or GFCI check involves testing the functionality of the RCD breaker (UK standard) or GFCI outlet (US standard) installed on the premises.

An RCD or GFCI circuit protects you from electrical shock by switching off the circuit immediately after an imbalance is detected between the current flowing in and the current flowing out. RCD breakers and GFCI outlets reduce the risk of fatalities or catastrophes that can result from an electrical fault.

The US GFCI circuits are more sensitive than the UK RCDs. They will switch off the circuit when a leakage current exceeding 5mA is detected while RCDs trip at 30mA.

An RCD or GFCI socket tester sends a tripping current to the RCD or GFCI circuit respectively to see if it will trip. This simulates a real accident and helps to see if the protective electrical devices will respond as expected.

What is polarity check in a socket tester?

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). This allows you to check the wiring of the consumer unit remotely from an outlet.

Advanced socket testers are 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 has a rubber over-mold that makes it quite comfortable in the hand. 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.

This unit is cULus listed, meaning that it meets 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 on both sides makes Sperry socket tester 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 the 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 that are visible even in a well-lit room
• The case has a reverse taper that makes this tool easier to plug in and out
• The front of the device has a graphic to interpret the LEDs patterns

Disadvantages

• User manual is not easy to read
• Will not detect 2 hot wires in a 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 make it difficult to tell if the light is on in the glare
• Has visual indicators only
• Will not indicate the quality of ground resistance
• Will not detect 2 hot wires in circuit

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 loose when a lot of force is used to push it into a socket outlet
• Will not detect 2 hot wires in circuit

Professional Socket Testers

Professional socket testers are more complex than advanced devices because they use additional components and technology to indicate loop impedance more accurately; either in numerical values or shorter ranges.

These outlet testers do everything else an advanced socket tester does and they conform to the BS EN 61557-3 standards. Therefore, electricians can use them to certify or report on an electrical installation.

Similar to advanced socket testers, a professional receptacle tester is also meant to be used by trained electricians.

How to Use a Socket Tester to Test AC Outlet

Always remember to unplug your socket tester from the wall socket and store it safely in the toolbag!