Hot-Line Proximity Alarms

A proximity alarm (live-line approach warning device) is a personal safety device worn by the worker that detects the electric field of a live conductor without contact and warns of a dangerous approach. It is used by overhead line crews on distribution networks, technicians maintaining medium-voltage cubicles and panels, and contractors working near energised installations. The aim is to provide an additional layer of warning at moments when attention lapses or a live section goes unnoticed.

How to choose the right model

• Voltage band worked on: Arm and helmet models are divided into three bands: AC 6.6 – 33 kV (HXA-6 / HXA-6S), AC 11 – 66 kV (HXA-30 / HXA-30S) and AC 66 – 110 kV (HXA-70 / HXA-70S). Among the wrist models, the HXW-6WL works at AC 400 V – 22 kV and the HXW-6W at AC 1 kV – 42 kV.
• Mounting and type of work: The wrist type gives the warning close to the hand in work where the hand reaches into cubicles and panels. The arm type is worn on the upper arm and provides continuous protection during overhead line work. The helmet type is mounted on the safety helmet and leaves the hands completely free.
• Sensitivity to low voltage: If you also want warnings in low-voltage panels, consider the HXW-6WL, which works from 400 V; on a 400 V line it starts alarming at a distance of about 25 cm.
• Alarm distance: The HXW-6W warns at about 60 cm on a 6.6 kV line. The actual distance varies with the voltage level, the position of the conductor and nearby earthed structures.

Subcategory	Models	Operating voltage	Typical use
Wrist Proximity Alarms	HXW-6WL, HXW-6W	AC 400 V – 22 kV / AC 1 kV – 42 kV	Cubicles, panels, distribution installations
Arm Proximity Alarms	HXA-6, HXA-30, HXA-70	AC 6.6 – 33 kV / 11 – 66 kV / 66 – 110 kV	Overhead line work
Helmet Proximity Alarms	HXA-6S, HXA-30S, HXA-70S	AC 6.6 – 33 kV / 11 – 66 kV / 66 – 110 kV	Hands-free overhead line work

Safe use

• A proximity alarm is an auxiliary warning device; it is not used to verify the absence of voltage. The pre-work check must be carried out with a suitable voltage detector.
• The absence of an alarm does not mean there is no live conductor nearby; minimum approach distances and personal protective equipment rules apply in all cases.
• Check the device before every shift and replace its battery regularly.

For a general overview, read our article What Is a Proximity Alarm?.

Frequently Asked Questions

How do I choose between the arm type and the helmet type?

Both types are offered in the same voltage bands; the difference is where they are worn. If your team has standardised on helmet use, the helmet type is suitable; if a warning at the arm is preferred, the arm type is the right choice.

Which model should I choose for a line at the boundary of two voltage bands?

For lines at the boundary of two bands, such as 33 kV or 66 kV, tell us about the other voltage levels your team works on as well; we will determine with you the model that covers all your field scenarios.