Ingco HSDT1908 Voltage Test Pencil 100–500V AC (190mm)

The Ingco test pencil is a compact voltage tester designed for basic AC checks across a 100–500V range, making it a practical site and toolbox essential.

Ideal for trade professionals, maintenance teams and DIY users, this screwdriver-style test pencil supports quick electrical checks before working on sockets, switches and wiring. Features neon bulb indication, slotted 4mm tip for dual functionality, and extended 190mm length for improved reach. Always follow safe working practices.

Key benefits

• AC voltage testing range: 100–500V for common electrical systems
• Screwdriver-style test pencil with slotted 4mm tip
• Extended 190mm length provides better reach than standard 140mm models
• Neon bulb indicator provides clear visual voltage confirmation
• Dual-function tool: voltage tester and medium slotted screwdriver
• Compact design fits easily in toolbags, pockets, and tool belts
• Low-cost essential add-on item for site work at £1.79
• Suitable for trade professionals and DIY applications
• Simple tool for basic electrical safety checks
• Lightweight and portable (approximately 80-100g)
• Durable high-quality construction with insulated handle
• No batteries required - always ready to use
• Safe and reliable for voltage testing
• Packed in plastic hanger for retail display and storage

Best for

• Quick voltage presence checks on AC circuits before work begins
• Testing sockets, outlets, switches, and light fixtures
• Identifying live wires and voltage presence in electrical installations
• Basic electrical maintenance tasks and fault finding
• Residential electrical work (120V/240V systems)
• Commercial and light industrial electrical testing
• Verifying circuits are de-energized before maintenance
• Emergency electrical troubleshooting
• Applications requiring extended reach compared to 140mm models
• Working in deeper electrical boxes and panels
• Keeping as an affordable spare in toolboxes, vans, and site kits
• DIY home electrical projects and repairs

Key features – why it matters

• AC 100–500V voltage range: suitable for testing common residential (120V/240V), commercial, and light industrial AC electrical systems - covers the most frequently encountered voltage levels in everyday electrical work - provides reliable detection across entire range
• Extended 190mm length: longer than standard 140mm test pencils, providing improved reach for deeper electrical boxes, recessed outlets, control panels, and hard-to-access areas - 50mm additional length makes significant difference in accessibility - reduces need to stretch or strain when testing
• Screwdriver-style test pencil format: classic electrician's tool combines voltage testing with medium screwdriver functionality - familiar design trusted by electricians worldwide - slim pen-style shape for convenient handling and storage
• 4mm slotted tip: wider than 3mm models, suitable for medium-sized terminal screws, outlet covers, electrical fittings, and switch plates - provides dual functionality as voltage tester and practical screwdriver for common electrical hardware - eliminates need to carry separate tool for adjustments
• Neon bulb visual indication: built-in neon bulb glows when voltage is detected - provides clear, unmistakable visual confirmation of live circuits - no batteries required (bulb operates from detected voltage) - simple and reliable indication method that never fails due to dead batteries
• No batteries required: neon bulb operates directly from detected AC voltage - always ready to use without battery concerns - eliminates ongoing battery replacement costs and dead battery failures - truly maintenance-free operation
• Lightweight portable (80-100g): minimal weight makes it effortless to carry all day - can keep multiple units in different locations (van, toolbox, home) without burden - won't weigh down pockets or tool belts
• Durable insulated construction: high-quality materials with insulated handle ensure safe operation and reliable performance in demanding work environments - built to withstand daily professional use - protects against electrical shock
• Affordable essential (£1.79): extremely low cost makes it accessible for everyone - affordable enough to keep multiple units as backups or distribute to team members - exceptional value for essential safety tool - minimal investment for critical safety equipment
• Safe and reliable: designed specifically for voltage testing safety - helps prevent electrical shock by identifying live circuits before physical contact - trusted design used by electricians for decades
• Simple operation: intuitive use requires no training - touch tip to conductor while holding finger on metal cap - neon bulb lights if voltage present - anyone can use effectively
• Compact yet functional: despite extended length, still compact enough to fit in shirt pockets, tool bags, and small storage compartments - always accessible when needed
• Plastic hanger packaging: convenient retail packaging with hanger for display and organized storage
• Versatile professional tool: essential for electricians, maintenance technicians, HVAC professionals, facilities managers, and serious DIYers - suitable for residential, commercial, and light industrial applications

Specifications

What's included

• 1 × Ingco AC 100–500V test pencil (HSDT1908)
• Plastic hanger packaging

How to use

• Follow electrical safety procedures: Always follow standard electrical safety practices including wearing appropriate personal protective equipment (PPE), assuming all circuits are live until proven otherwise, and following local electrical codes and regulations.
• Inspect test pencil before use: Check the test pencil for any physical damage, cracks in the insulation, or worn components. Do not use if damaged. Verify neon bulb is intact and insulation is not compromised.
• Test on known live circuit first: Before relying on the test pencil, verify it's functioning properly by testing on a known energized circuit. The neon bulb should glow when detecting voltage, confirming the tool is operational.
• Hold test pencil correctly: Grip the insulated handle of the test pencil securely. Place your finger or thumb on the metal cap or contact point at the top end of the pencil (this completes the circuit through your body to ground, allowing the neon bulb to light).
• Touch tip to conductor: Touch the slotted metal tip to the electrical conductor, terminal, or contact point you wish to test. For outlets, insert tip into outlet slot. For exposed wires or terminals, touch directly to conductor. The extended 190mm length provides better reach for recessed or hard-to-access areas.
• Observe neon bulb indication: If AC voltage is present within the 100-500V range, the neon bulb inside the test pencil will glow/light up. No glow indicates absence of voltage (circuit is de-energized or voltage is outside detection range).
• Test multiple points: For thorough verification, test multiple points in the circuit (both slots of an outlet, multiple terminals, etc.) to ensure complete understanding of circuit status.
• Use screwdriver function when safe: Once voltage is confirmed absent, the slotted 4mm tip can be used as a medium screwdriver for loosening/tightening terminal screws, outlet covers, switch plates, and electrical fittings.
• Confirm results appropriately: For critical applications or professional electrical work, confirm test pencil results using additional testing methods such as a multimeter or non-contact voltage detector.
• Never assume circuits are safe: Even if test pencil shows no voltage, follow proper lockout/tagout procedures and use appropriate verification methods before working on electrical systems.

Care & maintenance

• Keep the test pencil clean and dry at all times.
• Wipe with dry cloth to remove dust, dirt, and contaminants.
• Do not immerse in water or expose to moisture.
• Store in a tool case, organiser, or protective sleeve to protect the tip and body from damage.
• Inspect regularly for cracks, damage to insulation, worn tip, or broken neon bulb.
• Replace immediately if damaged, showing signs of wear, or if neon bulb no longer functions.
• Do not drop or subject to severe impact.
• Avoid exposure to extreme temperatures, chemicals, or solvents that could degrade insulation.
• Test regularly on known live circuits to verify proper operation.
• Do not attempt to repair or modify - replace if faulty.
• Keep away from children when not in use.
• Store in dry location away from moisture and corrosive environments.
• Check insulation integrity regularly for safety.

Safety warnings

• Basic screening tool only: This test pencil is a basic voltage detection tool, not a comprehensive electrical testing instrument. Always use appropriate testing equipment and follow proper electrical safety procedures.
• Limited voltage range: Only detects AC voltage between 100-500V. Will not detect voltages below 100V (including many low-voltage circuits) or above 500V. Will not detect DC voltage.
• Not a precision instrument: Does not provide accurate voltage readings - only indicates presence or absence of voltage. Use multimeter for precise measurements.
• Requires body contact: Must complete circuit through your body to ground for neon bulb to light. This is inherent to the design but means you become part of the circuit.
• Always verify with additional methods: For critical applications, verify test pencil results with multimeter or other testing equipment.
• Assume all circuits are live: Never assume a circuit is safe based solely on this tool. Always follow lockout/tagout procedures.
• Wear appropriate PPE: Use insulated gloves, safety glasses, and other protective equipment when working with electrical systems.
• Qualified personnel only: Electrical work should only be performed by qualified personnel familiar with electrical safety.
• Follow local codes: Always comply with local electrical codes and regulations.
• Do not use if damaged: Replace immediately if cracked, damaged, or neon bulb is broken. Damaged insulation poses serious shock hazard.
• Environmental limitations: May not function reliably in all conditions. Verify operation before critical use.
• Never use on circuits above 500V: This tool is rated only for 100-500V AC. Do not use on higher voltage systems.

Accessories & add-ons

• Non-contact voltage detectors (VD100026) for safer contactless testing
• Digital multimeters for precise voltage, current, and resistance measurements
• Clamp meters for AC/DC current measurement
• Insulated screwdrivers and hand tools
• Shorter 140mm test pencil (HSDT1408) for more compact applications
• Wire strippers and cable cutters
• Electrical PPE (insulated gloves, safety glasses, arc flash protection)
• Tool belts and storage pouches
• Protective carrying cases for test equipment
• Additional test pencils for backup and multiple locations

Delivery & returns

Free UK delivery on orders over £50. 28-day returns apply.

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FAQs

What voltage range does this test pencil cover?

This test pencil is designed for AC 100–500V checks. It detects alternating current voltage within this range, covering common residential (120V/240V), commercial, and light industrial electrical systems. It will not detect voltages below 100V or above 500V, and it does not work with DC (direct current) voltage.

What is the difference between the 190mm and 140mm models?

The HSDT1908 (190mm) is 50mm longer than the HSDT1408 (140mm) model and features a 4mm slotted tip compared to the 3mm tip on the shorter version. The extended length provides better reach for deeper electrical boxes, recessed outlets, and hard-to-access areas. The wider 4mm tip is suitable for medium-sized screws and fittings. Choose the 190mm model when extended reach is beneficial, or the 140mm for maximum portability.

Is this suitable for household electrics?

Yes, it can be used for basic AC voltage checks on household electrical systems including standard 120V and 240V circuits, outlets, switches, and light fixtures. The extended 190mm length is particularly useful for deeper outlet boxes and recessed fixtures. However, safe working practices must always be followed, including wearing appropriate PPE, following local electrical codes, and verifying results with additional testing methods when appropriate.

Is this a screwdriver-style voltage tester?

Yes, this is a classic screwdriver-style test pencil with a slotted 4mm tip. It combines voltage testing functionality with a medium slotted screwdriver for dual-purpose use. The pen-style format with slotted tip allows you to test for voltage and also perform screwdriver tasks on terminal screws, outlet covers, and switch plates.

Does it need batteries?

No, this test pencil does not require batteries. The neon bulb indicator operates directly from the detected AC voltage in the circuit being tested. This means it's always ready to use without battery concerns, eliminates ongoing battery costs, and prevents dead battery failures. The neon bulb lights when voltage is present by using the electrical current from the circuit.

How long is the test pencil?

The test pencil measures 190mm in overall length with a 4mm slotted tip width (designated as 4×190mm). This extended length provides 50mm more reach than standard 140mm test pencils, making it ideal for deeper electrical boxes and hard-to-access areas while still remaining portable enough to carry in pockets and tool bags.

Is this suitable for trade use?

Yes, it is suitable for basic voltage checks in trade and DIY settings. Many electricians and tradespeople keep these affordable test pencils as quick screening tools and backups. The extended 190mm length is particularly appreciated by professionals working in deeper electrical panels and junction boxes. However, for professional electrical work, it should be used alongside comprehensive testing equipment like multimeters and should follow proper electrical safety procedures.

Do you sell other electrical testing tools?

Yes. A range of voltage detectors (including non-contact models like VD100026), shorter 140mm test pencils (HSDT1408), digital multimeters, clamp meters, and professional testing tools are available for comprehensive electrical testing and troubleshooting needs.

How does the neon bulb indication work?

The neon bulb inside the test pencil lights up (glows) when AC voltage is detected. To use it, you hold your finger on the metal cap at the top while touching the slotted tip to the conductor being tested. This completes the circuit through your body to ground. When voltage (100-500V AC) is present, a small current flows through the neon bulb, causing it to glow visibly. No glow means no voltage is detected.

Can I use this as a regular screwdriver?

Yes, the slotted 4mm tip can be used as a medium screwdriver for terminal screws, outlet covers, switch plates, and other 4mm slotted applications. The 4mm size is suitable for more applications than the narrower 3mm models. However, only use the screwdriver function after confirming the circuit is de-energized. Never use as a screwdriver on live circuits. The primary function is voltage testing, with screwdriver use as a secondary convenience feature.

Will it detect low-voltage circuits?

No, this test pencil only detects AC voltage from 100V minimum. It will not detect low-voltage circuits below 100V such as 12V, 24V, or 48V systems commonly used in doorbells, thermostats, lighting transformers, and control circuits. For low-voltage testing, use a multimeter or specialized low-voltage detector like the VD100026 which detects from 12V.

Does it work on DC voltage?

No, this test pencil is designed exclusively for AC (alternating current) voltage detection from 100-500V. It will not detect DC (direct current) voltage. For DC voltage testing, use a digital multimeter with DC voltage measurement capability.

How do I know if it's working properly?

Before each use, test the pencil on a known live circuit (such as a working outlet) to verify the neon bulb lights up when voltage is present. This confirms the tool is functioning properly. If the neon bulb doesn't light on a known live circuit, the tool may be damaged or the neon bulb may be burned out - replace the test pencil immediately.

Why should I choose the 190mm model over the 140mm?

Choose the 190mm model (HSDT1908) when you need extended reach for deeper electrical boxes, recessed outlets, control panels, or hard-to-access areas. The extra 50mm length makes a significant difference in accessibility. The 4mm tip is also more versatile than the 3mm tip. Choose the 140mm model (HSDT1408) if maximum compactness and pocket portability are your priorities. Many electricians keep both sizes for different applications.

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