Voltage Detectors

A voltage detector is a safety device used to verify, before work starts, whether a conductor or piece of equipment is live. For field crews of distribution network operators (DSOs), maintenance electricians at industrial sites, substation and switchyard staff and electrical contractors, it is the first step in the decision that a circuit is dead.

In everyday language, "voltage detector" often brings to mind the simple tester pens used on sockets and building wiring. The HASEGAWA range, by contrast, is designed for professional use and extends from low voltage up to AC 550 kV. If you are looking for a detector for panels, sockets and cables, go straight to low-voltage detectors; medium- and high-voltage models are listed with their voltage ranges in the table below.

How to choose the right model

• Voltage class and type of current: Establish the nominal voltage of the system you will work on and whether it is AC or DC. The detector's operating range must cover this value. For DC circuits, choose models with a defined DC range (e.g. HTE-700D/700DL, HST-1.5N, HST-20N, HSR-90N).
• Access to the conductor: Compact hand-held detectors may be sufficient inside panels; on overhead lines and in switchyards you need to reach the conductor from a safe distance with an insulating stick (hot stick).
• Existing stick inventory: If you already have universal operating sticks, universal-joint detectors attach to them via a universal joint; if not, consider models supplied with their own telescopic stick.
• Spot check or continuous indication: Portable detectors are used for pre-work checks; fixed Voltect indicators are used at points where the presence of voltage must be shown continuously.
• Verification in the field: Keep a compatible voltage detector tester so you can check the detector before use.

Subcategory	Typical use	Operating voltage (combined coverage of the models)
Low-Voltage Detectors	Panel, socket and cable checks	AC 50 V – 1000 V; DC 12 V – 750 V (HTE-700D/700DL)
Medium / Low-Voltage Detectors	Distribution networks, transformer maintenance	AC 60 V – 36 kV; DC 600 V – 7 kV (HST-1.5N)
Hot-Stick High-Voltage Detectors	Overhead lines, switchyards	AC 3 kV – 550 kV; DC 3 kV – 90 kV (HST-20N, HSR-90N)
Universal-Joint High-Voltage Detectors	Use with a universal operating stick	AC 1 kV – 550 kV
Voltect Voltage Indicators	Fixed installation, continuous indication	AC 3.3 kV – 550 kV

The ranges in the table are those covered by the models of each subcategory together; no single model covers the whole range. Model-specific ranges are given on the product pages.

Safe use

• Check that the detector works before every use; never decide that a circuit is dead using a device you suspect is faulty.
• Use the detector only within its operating range and with personal protective equipment suited to the voltage class.
• Once the absence of voltage has been verified, do not start work until the work location has been earthed with suitable earthing equipment.
• Proximity alarms are an additional layer of warning; they do not replace a voltage detector.

For a more detailed comparison, see our article How to Choose a Voltage Detector.

Frequently Asked Questions

Is there a difference between a voltage tester pen and a low-voltage detector?

In everyday language the terms are often used interchangeably. HASEGAWA low-voltage detectors are designed for professional panel and cable work; the HTE-610W, for example, offers detection through the cable sheath, sensitivity adjustment and measurement category CAT III 1000 V.

Which detector should I choose for medium voltage up to 36 kV-class switchgear?

For checks inside cubicles and panels, the HSS-36B1 (AC 80 V – 36 kV) can be considered; for overhead lines up to 34.5 kV, the hot-stick HST-30 / HST-30L (AC 3 kV – 34.5 kV). Tell us about your application and we will confirm the right model with you.