HST-20N AC/DC Hot Stick Voltage Detector

HASEGAWA HST-20N is an AC/DC hot stick voltage detector operating in the 3 kV – 25 kV range on both alternating and direct voltage. It was developed for teams that need to check AC medium voltage networks and DC high voltage systems with a single instrument. Manufactured in Japan by Hasegawa Electric, the HST-20N is supplied by HASEGAWA Türkiye, the official HASEGAWA distributor in Türkiye, to customers across Europe.

The body weighs approximately 610 g and runs on two LR44 cells. It starts to give an indication at 1000 V ± 20% to earth, and this threshold is the same on the AC and DC sides. Its main users are distribution maintenance teams, high voltage laboratories working with DC test set-ups and maintenance staff at industrial sites with both AC and DC equipment.

Where is it used?

• AC medium voltage: cubicle and line checks at distribution levels up to 25 kV, such as 10 kV, 15 kV and 20 kV.
• DC high voltage systems: confirming absence of voltage after the circuit has been opened in supply and test set-ups fed with DC voltage within the range.
• Test laboratories: checking after a test that the AC or DC source has actually been disconnected.
• Mixed industrial sites: working with one detector where AC distribution and DC process equipment are installed side by side.

HST-20N or HSR-90N?

	HST-20N	HSR-90N
Operating voltage (AC)	3 kV – 25 kV	6 kV – 90 kV
Operating voltage (DC)	3 kV – 25 kV	6 kV – 90 kV
Starting voltage (AC)	1000 V ± 20%	1000 V ± 20%
Starting voltage (DC)	1000 V ± 20%	3000 V ± 20%
Dielectric strength	AC 50 kV, 1 minute	AC 180 kV, 1 minute
Battery	LR44 × 2	LR03 / R03 × 2
Body weight	Approx. 610 g	Approx. 1500 g

For applications that do not exceed 25 kV, the HST-20N is the lighter solution. If you also have AC/DC systems at 30 kV, 33 kV or 66 kV, you need the HSR-90N. If you work only on AC lines up to 33 kV, the HST-30 can be considered.

Technical specifications

• Operating voltage: AC 3 kV – 25 kV and DC 3 kV – 25 kV
• Starting voltage: 1000 V ± 20% (AC and DC, to earth)
• On insulated cable: cannot be used
• Frequency: 50/60 Hz
• Dielectric strength: AC 50 kV between contact tip and earth terminal for 1 minute
• Leakage current: 0.5 mA or less during the withstand test
• Battery: 2 × LR44 (1.5 V), approx. 4 hours of continuous operation
• Operating temperature: −10 °C … +40 °C
• Weight: approx. 610 g (body only)

Limits of use and safety

The technical table states clearly that the HST-20N cannot be used on insulated cable; always test by contact with the exposed conductor. Lines at 30 kV or 33 kV exceed the instrument's 25 kV upper limit and must not be tested with it. In DC systems, capacitive components such as cables and capacitors can retain a charge after the supply has been switched off; discharge it with discharge sticks and see our discharge stick guide for details. Test the instrument with a suitable voltage detector tester before every measurement; for the DC side we can check together whether testers such as the HLA-N2 DC are compatible. Wear gloves rated for the voltage class and earth the circuit once the absence of voltage has been verified.

Why buy from HASEGAWA Türkiye?

• We review your AC and DC systems together and confirm whether the HST-20N or the HSR-90N is the right choice
• Complementary products such as a DC tester and discharge sticks can be combined in one order
• We prepare formal quotations with a commercial invoice for laboratory and industrial purchasing