HF-GT-221 Ground Resistance Tester Calibrator

Description

HF-GT-221 Ground Resistance Tester Calibrator is a safety‑type instrument adopting potential‑compensation principle. Simple‑to‑operate and portable, it is widely used for ground‑resistance measurement of single and concentrated grounding electrodes to monitor grounding quality and ensure electrical safety.

It complies with JJG366‑2004 national verification regulation for ground‑resistance testers. As a standard instrument for calibrating analog and digital ground resistance testers of various accuracy classes and models. Not applicable for ground‑conductive type testers with AC 25A working current. It can also act as resistance box; starting resistance:10 mΩ, resolution:1 mΩ.

Main Technical Specifications

Resistance Output Range

0.010 Ω ~ 11111.110 Ω; minimum resolution: 1 mΩ

Simulated Ground Resistance rE (Standard Resistor)

Resistance Value (Ω)	×10³	×10²	×10¹	×10⁰	×10⁻¹	×10⁻²	×10⁻³
Power / Current	0.25 W	0.25 W	0.25 W	0.25 W	0.5 A	0.5 A	0.5 A
Accuracy (%)	0.1	0.1	0.1	0.1	0.5	5	10

Simulated Auxiliary Ground Resistance rP, rC (Auxiliary Earth Resistance)

Resistance Value (Ω)	0	500	1000	2000	5000
Accuracy	＜0.1Ω	2.0%	2.0%	2.0%	2.0%
Power	colspan=”5″	rP:0.5 W rC:2 W

General Parameters

Item	Specification
Operating Environment	Temperature: 20℃±5℃; Relative Humidity:40%‑75%
Weight	＜3 kg
Dimensions	370 mm × 265 mm × 140 mm

Packing List — Ground Resistance Tester Calibrator

Item	Qty	Remarks
Main Calibrator Unit	1 pc	HF-GT-221 ground resistance tester calibrator
Connection Test Leads	1 set	For signal connection
Grounding Wire	1 pc	Safety ground connection
Power Supply Cord	1 pc	Mains power input
User Manual	1 copy	Chinese & English version
Factory Calibration Certificate	1 copy	Metrology calibration document
Portable Protective Carrying Case	1 pc	For field transport and storage

FAQ — Ground Resistance Tester Calibrator

Q1: What principle does this calibrator adopt?

A1: It works on the potential‑compensation principle. It is a standard instrument compliant with JJG366‑2004 for calibrating ground resistance testers.

Q2: What is its resistance output range and resolution?

A2: Output range: 0.010 Ω ~ 11111.110 Ω, minimum resolution reaches 1 mΩ. It can also be used independently as a resistance box.

Q3: Which types of testers can it calibrate?

A3: It calibrates various analog and digital ground resistance testers of different accuracy grades. Not suitable for ground‑conductive type testers with working current AC 25A.

Q4: What about simulated auxiliary earth‑resistance function?

A4: It provides simulated auxiliary ground resistance rP and rC with selectable values: 0Ω, 500Ω, 1000Ω, 2000Ω, 5000Ω, to simulate real‑site grounding test conditions.

Q5: What are the accuracy specifications for resistance decades?

A5: High‑value decades ×10³~×10⁰: accuracy 0.1%; low‑value decades have corresponding accuracy parameters, please refer to technical table for full details.

Q6: What are the required operating environmental conditions?

A6: Operating temperature: 20℃±5℃; relative humidity: 40%‑75%.

Q7: What are the physical parameters of the instrument?

A7: Weight ＜3 kg; dimensions: 370 mm × 265 mm × 140 mm, portable for laboratory use.

Q8: Can it be used for field measurement besides calibration?

A8: It is mainly designed as a calibration standard source. It can also measure grounding resistance of single or concentrated grounding electrodes to assess grounding quality.