HPI-S20W Medium / High Voltage Phase Tester

HASEGAWA HPI-S20W is a medium-voltage phase tester whose transmitter and receiver units are linked by fibre-optic cable, developed for 22 kV – 42 kV overhead lines. The optical link provides electrical isolation between the two test points. Common 33 kV and 35 kV distribution lines sit well within its operating range. The HPI-S20W is manufactured in Japan by Hasegawa Electric and supplied as a genuine HASEGAWA product by HASEGAWA Türkiye, the official distributor in Türkiye.

Before two lines or two supply sources are connected, the instrument checks phase agreement (in phase / 120° out of phase) and phase sequence (120° leading / lagging). DSO operations and maintenance crews use it for ring network switching and new line connections.

How does the phase tester work?

The units, mounted on the ends of two telescopic insulated sticks, are brought into contact with the two conductors being compared at the same time. The transmitter sends information on the phase it is touching to the receiver over the optical cable; the receiver compares it with the phase it is touching and reports the result visually and audibly. The visual indication is readable at 8000 lux, and the audible warning is at least 50 dB at 1 m on the receiver side.

The standard package gives a test distance of 6 m with two 3 m optical cables; with an optional optical cable, this can be extended to 30 m. This is a significant advantage where phases must be compared between two poles or disconnectors that are far apart.

HPI-S20W or HPR?

	HPI-S20W	HPR-S20 / HPR-U20
Operating voltage	AC 22 kV – 42 kV	Shared use at 22 kV and 34.5 kV
Link between units	Fibre-optic cable	Wireless
Phase test distance	6 m standard, up to 30 m optional	Within 5 m
Audible indication	At least 50 dB at 1 m	At least 50 dB at 3 m
Battery	2 × 1.5 V R1 per unit	1 × LR03 or R03 per unit
Stick	Telescopic, approx. 1665 mm × 2	Straight (S20) or universal-joint (U20)

If phases must be compared between distant points, the HPI-S20W's optical link, extendable to 30 m, is the stronger choice; if you prefer a wireless, lighter set, consider the HPR series.

Technical specifications

• Operating voltage: AC 22 kV – 42 kV, 50/60 Hz; threshold 1500 V ± 20 %
• Phase test: in phase / 120° out of phase; phase sequence: 120° leading / lagging
• Test distance: 6 m (3 m × 2), up to 30 m with optional cable
• Dielectric withstand: AC 75 kV, 1 minute, between sticks spaced 30 cm apart
• Insulation resistance: 2000 MΩ or more (1000 V megger)
• Battery: 2 × 1.5 V R1 per unit
• Operating temperature: −10 °C … +40 °C

Limits of use and safety

The HPI-S20W is a phase comparison instrument and is not used to verify the absence of voltage; for that you need a hot stick high voltage detector of the appropriate class. Do not use the instrument on lines below 22 kV or above 42 kV. Do not crush or sharply bend the optical cables, and check before use that the sticks are clean, dry and undamaged. The two people carrying out the test must hold the sticks only at the handle area and wear protective equipment suitable for the MV class. For the basic steps of a phase test, see our phase tester guide.

Why buy from HASEGAWA Türkiye?

• A side-by-side recommendation between the HPI-S20W and the HPR series for your 33 kV-class ring switching
• We add the optional 30 m optical cable and spare accessories to your order
• Multi-set quotations in one go for network regions and contractors