HXA-70S Helmet-Mounted Proximity Alarm

HASEGAWA HXA-70S is a helmet-mounted proximity alarm for overhead lines at the 66 kV – 110 kV transmission level. Fixed to the safety helmet, the device monitors the electric field around the live conductor and gives an audible warning of at least 65 dB on a dangerous approach. It is the member of the helmet-mounted HXA series with the highest voltage range.

According to the theoretical values in the current catalogue, the alarm activates at about 2.1 m on a 66 kV line and about 2.7 m on a 110 kV line. This provides an early warning consistent with the larger safety clearance needed at high voltage. The HXA-70S is manufactured in Japan by Hasegawa Electric and supplied as a genuine HASEGAWA product by HASEGAWA Türkiye, the official distributor in Türkiye.

Where is it used?

The HXA-70S adds an extra awareness layer, positioned at the protected head, for work close to the transmission network:

• Tower and pole-top maintenance on 66 kV and 110 kV overhead lines
• Conductor and fitting work on a de-energised circuit running parallel to a live one
• Field work on high-voltage line connections entering substations
• Aerial platform work under or near high-voltage lines

While the worker's arms are constantly moving, the helmet consistently represents the position of the head as it moves towards the conductor. With the sound source close to the ear, the warning is easier to hear at windy, noisy heights.

HXA-70S or HXA-30S?

	HXA-6S	HXA-30S	HXA-70S
Operating voltage	AC 6.6 kV – 33 kV	AC 11 kV – 66 kV	AC 66 kV – 110 kV
Theoretical alarm distance at 11 kV	1.4 m	1.0 m	0.8 m
Theoretical alarm distance at 33 kV	2.5 m	1.7 m	1.5 m
Warning	Audible + flashing LED	Audible + flashing LED	Audible + flashing LED
Protection	IP67	IP67	IP67
Frequency	50/60 Hz	50/60 Hz	50/60 Hz
Sound level	At least 65 dB at 1 m	At least 65 dB at 1 m	At least 65 dB at 1 m
Battery	CR2032 (3 V) × 1, ~1 year standby	CR2032 (3 V) × 1, ~1 year standby	CR2032 (3 V) × 1, ~1 year standby
Weight (body only)	Approx. 45 g	Approx. 45 g	Approx. 45 g
Dimensions	94 × 48 × 27.5 mm	94 × 48 × 27.5 mm	94 × 48 × 27.5 mm

The helmet-mounted models share the same body; they differ in the voltage class to which the detection threshold is set. The HXA-30S is preferred on 11 kV – 66 kV distribution and sub-transmission lines, and the HXA-6S on networks up to 33 kV. The equivalent arm-mounted model, the HXA-70, is designed for the same voltage class; the choice between the two depends on where the crew prefers to wear the device.

Current HXA Series catalogue features

According to the current HASEGAWA HXA Series brochure, the helmet-mounted models (HXA-6S, HXA-30S, HXA-70S) offer:

• Audible and visual warning: buzzer plus flashing LED when a live part is approached; at least 65 dB at 1 m.
• No power switch: always on standby, so it cannot be left switched off.
• IP67 dust and water protection (IEC 60529): dust-tight and protected against temporary immersion.
• Long standby life: about 1 year on standby and about 15 hours of continuous alarm from one CR2032 battery.
• Light body: about 45 g.
• International references: the brochure lists EN 61326-1 Class B, CISPR 11:2015, EN 61010-1, IEC TR 61243-6 and ASTM F3283/F3283M-18; the series has passed EMC testing (IEC 61000-4-2, IEC 61000-4-3, IEC 61000-4-8).
• Made in Japan under strict quality control.

Theoretical alarm distances by line voltage

Line voltage (phase-to-phase)	HXA-6S	HXA-30S	HXA-70S
6 kV	1.1 m	0.7 m	0.6 m
11 kV	1.4 m	1.0 m	0.8 m
22 kV	2.0 m	1.4 m	1.2 m
33 kV	2.5 m	1.7 m	1.5 m
66 kV	3.5 m	2.3 m	2.1 m
110 kV	4.5 m	3.0 m	2.7 m

The values are theoretical, under standard conditions. Real alarm distance varies with conductor arrangement, surrounding structures, earthing conditions and the work environment; verify operation on site. The HXA Series is an auxiliary warning device and does not replace required safety clearances or verification of absence of voltage.

Technical specifications

• Operating voltage: AC 66 kV – 110 kV
• Theoretical alarm distance: about 2.1 m on a 66 kV line, about 2.7 m on a 110 kV line (standard conditions)
• Frequency: 50/60 Hz
• Sound level: at least 65 dB
• Battery: 1 × JIS CR2032 (3 V); about 1 year on standby, about 15 hours of continuous alarm
• Warning: audible (buzzer) and flashing LED; no power switch, always on standby
• Protection: IP67 (IEC 60529)
• Permissible temperature: −10 °C … +40 °C, without condensation on the surface or inside
• Weight and size: approx. 45 g (body), 94 × 48 × 27.5 mm
• Accessories: fastening band and 2 holders

Limits of use and safety

The HXA-70S does not replace verification of absence of voltage. Before starting work on lines up to 110 kV, verify that the line is de-energised with a hot stick high voltage detector of the appropriate voltage class, then earth the work area. Our article on earthing sets explains how to apply earthing correctly. Because the alarm start distance can vary with site conditions, the minimum approach distance defined in the permit to work always takes priority.

Make sure there is no condensation on the body, and check the battery and holder attachment before each shift. Insulating gloves, a safety harness and other PPE continue to be used together with this device.

For model selection and correct use in the field, see our Helmet-Mounted Proximity Alarm guide.

Why buy from HASEGAWA Türkiye?

• We help your transmission and substation maintenance crews choose the right alarm type in the 66 kV – 110 kV class
• The alarm, a suitable voltage detector and earthing sets combined in a single quotation
• Commercial invoice suitable for public- and private-sector projects, with genuine products from the official distributor in Türkiye