Best Bosch Socket Tester of 2026
Choosing the right Bosch socket tester ensures your electrical outlets are wired correctly and safe. We compared the latest models to help you find the best tool for your home or professional kit.
Quick answer
The Bosch GKT 55 G6 Professional Socket Tester is our top pick for its robust build and clear RCD indication. For a budget-friendly option that covers all standard wiring checks, the Bosch ATG 2-20 is the best value choice for DIYers.
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Research updated June 2026.
Bosch GKT 55 G6 Professional
Professional-grade RCD testing and wiring fault detection.
| Product | Best For | Key Spec | Rating | Price |
|---|---|---|---|---|
| Bosch GKT 55 G6 | Overall / Pro | RCD 30 mA test | 4.6/5 | $$$ |
| Bosch ATG 2-20 | Budget / DIY | LED fault display | 4.3/5 | $ |
| Bosch GKT 35 | Compact / Travel | Pocket size | 4.1/5 | $$ |
| Bosch Professional GKT 70 | Advanced Diagnostics | Voltage & phase test | 4.5/5 | $$$ |
| Bosch EasyTest | Beginner / Home | Simple LED codes | 4.0/5 | $ |
Bosch GKT 55 G6 Professional
Best OverallPros
- Integrated RCD test button
- Clear LED fault indicators
- Durable rubber housing
Cons
- Higher price point
- No voltage display
The Bosch GKT 55 G6 is a professional socket tester designed for electricians and serious DIYers. It checks for all common wiring errors including reversed polarity, missing earth, and live/neutral swap. The built-in RCD test function lets you verify that your residual current device trips within the required 30 mA threshold.
Owner reviews highlight its robust construction and reliable performance on UK and EU sockets. The rubber armored casing protects it from drops on job sites. While it lacks a digital voltage readout, its straightforward LED system makes fault identification instant.
Bosch ATG 2-20
Best BudgetPros
- Very affordable
- Simple LED fault codes
- Compact and lightweight
Cons
- No RCD test function
- Plastic feels less durable
The Bosch ATG 2-20 is an entry-level socket tester ideal for homeowners who need to check basic wiring. It uses three LEDs to indicate correct wiring or common faults like missing earth or reversed polarity. The tool is small enough to keep in a drawer for quick checks.
User feedback notes that it works reliably for standard 230V sockets. It does not include an RCD trip test, so it is best for simple verification rather than full safety compliance. The plastic build is adequate for occasional use but may not survive heavy drops.
Bosch GKT 35
Best CompactPros
- Very portable design
- Detects most wiring faults
- Good build quality
Cons
- No RCD test
- Smaller LEDs harder to read
The Bosch GKT 35 is a pocket-sized socket tester that fits easily in a tool pouch or pocket. It checks for six common wiring faults including live/neutral reversal and missing earth. The compact form factor makes it a favorite for electricians who need a quick check tool on the go.
Reviews note that the LEDs are smaller than on full-size testers, which can be a minor inconvenience in bright light. It does not include an RCD test function, so it is best used as a quick verification tool rather than a comprehensive safety tester.
Bosch Professional GKT 70
Best AdvancedPros
- Digital voltage display
- Phase rotation test
- RCD trip test included
Cons
- Bulkier design
- Higher cost
The Bosch Professional GKT 70 is a comprehensive socket and voltage tester for advanced users. It includes a digital display for voltage readings, phase rotation testing for three-phase systems, and an RCD trip test. This makes it suitable for industrial and commercial applications.
Owner reviews praise its accuracy and the clarity of the digital readout. The larger size means it is less portable than the GKT 35, but the additional features justify the bulk for professionals who need detailed diagnostics. It is the most feature-rich option in this roundup.
Bosch EasyTest
Best BeginnerPros
- Lowest price
- Extremely simple to use
- Good for basic checks
Cons
- Limited fault detection
- No RCD test
The Bosch EasyTest is the most basic and affordable socket tester in the lineup. It uses just two LEDs to indicate correct wiring or a fault. It is designed for homeowners who want a simple pass/fail check without interpreting multiple light patterns.
User reviews indicate it is reliable for detecting major issues like missing earth or reversed polarity. It does not detect all possible faults and lacks any RCD testing capability. The plastic housing is lightweight but feels less robust than the professional models.
What to check before buying a Bosch socket tester
Consider the types of sockets you need to test. Most Bosch testers work with standard 230V outlets, but the GKT 70 also handles three-phase systems. Check if you need RCD testing for safety compliance or just basic wiring verification. Build quality matters for job site use, while plastic models suffice for home storage.
Mistakes to avoid
Do not assume all socket testers detect every fault. Basic models miss issues like high resistance or intermittent faults. Avoid using a tester without reading the LED code chart first. Never rely on a socket tester as a substitute for a professional electrical inspection.
How do Bosch socket testers work?
Bosch socket testers plug directly into a standard electrical outlet. They use internal circuitry to detect wiring faults by comparing voltage between live, neutral, and earth wires. LEDs or digital displays then indicate the specific fault or confirm correct wiring.
Are Bosch socket testers suitable for professional electricians?
Yes, models like the GKT 55 G6 and GKT 70 are designed for professional use. They include RCD trip testing and detect more fault types than basic models. Professional electricians often prefer the GKT 70 for its voltage display and phase rotation test.
FAQs
What does a Bosch socket tester check?
It checks for common wiring faults like reversed polarity, missing earth, and live/neutral swap. Some models also test RCD trip functionality.
Can a Bosch socket tester test RCDs?
Only specific models like the GKT 55 G6 and GKT 70 include an RCD test button. Basic models like the ATG 2-20 do not have this feature.
Are Bosch socket testers safe to use?
Yes, they are designed to be safe for non-contact testing. Always follow the included instructions and do not insert metal objects into the socket.
Do Bosch socket testers work on US outlets?
Most Bosch testers are designed for UK/EU 230V sockets. Check the product specifications for compatibility with US 120V systems.
What is the difference between GKT 55 and GKT 70?
The GKT 55 focuses on RCD testing and fault detection, while the GKT 70 adds a digital voltage display and phase rotation test for advanced diagnostics.
Can I leave a socket tester plugged in?
It is safe for short periods, but do not leave it plugged in indefinitely. Remove it after testing to avoid wear on the tester or socket.
How do I read the LED codes on a Bosch tester?
Each model includes a reference card or label showing the LED patterns. Match the lit LEDs to the chart to identify the specific wiring fault.
Which Bosch socket tester is best for home use?
The Bosch ATG 2-20 is the best value for home use. It covers the most common faults at an affordable price.
Do Bosch socket testers require batteries?
No, they draw power from the socket being tested. No batteries are needed for operation.
What is the warranty on Bosch socket testers?
Bosch typically offers a 2-year warranty on their testers. Professional models may have extended warranty options.
Our verdict
For most users, the Bosch GKT 55 G6 Professional is the best overall socket tester due to its RCD test function and durable build. If you are on a budget, the Bosch ATG 2-20 provides reliable basic fault detection at a lower cost. Professionals needing advanced diagnostics should choose the Bosch Professional GKT 70.