# GPT-9904 Instek HiPot New

## GW Instek GPT-9904 — AC 500VA AC/DC Withstanding Voltage/Insulation Resistance/Ground Bond Tester

### Key Features at a Glance

-   **AC withstanding output:** 0.100kV–5.000kV ac, 500 VA (5kV/100mA), 2V/step, True RMS current measurement with 1μA resolution
-   **DC withstanding output:** 0.100kV–6.000kV dc, 100W (5kV/20mA), 2V/step resolution
-   **Insulation resistance:** 50V–1000V dc output, range 0.001GΩ–50.00GΩ (Insulation Resistance Measurement up to 50GΩ), 50V/step
-   **Ground bond:** 3.00A–32.00A ac output, four-terminal, 10mΩ–650.0mΩ range, 0.1mΩ resolution
-   **Sweep Function for DUT Characteristic Analysis:** Trace-graph display of test results during the whole measurement process (special MANU mode)
-   **Safety features:** Zero Crossing Turn-On, 150μs fast cutoff on fault, automatic DUT discharge after test, Safety Interlock
-   **Memory:** 100 MANU blocks + 100 AUTO blocks (menu per auto : 16), each step individually named
-   **Interface:** RS-232C, USB Device, Signal I/O, front-panel Remote Terminal, Rear Panel Output — GPIB optional

### Summary

In summary, the GW Instek GPT-9904 is a 4-in-1 electrical safety analyzer combining AC withstanding (5kVac/100mA from a 500VA PWM platform), DC withstanding (6kVdc/20mA), insulation resistance (DC 50V–1000V, up to 50GΩ), and AC ground bond (32A max., 10mΩ–650mΩ) testing in one production-ready instrument with Sweep Function and Rear Panel Output. It is built on a high-efficiency PWM switching amplifier designed to impede the influence caused by voltage fluctuation of input AC source, drives a 240×64 Ice Blue Dot Matrix LCD with high-intensity flash for caution & status indication, stores up to 100 MANU and 100 AUTO test blocks (menu per auto : 16), and supports RS-232C, USB Device, Signal I/O, and front-panel Remote Terminal standard interfaces with GPIB optional. The output voltage is automatically cut off (within 150μs) upon the detection of an abnormal output voltage or a trip of current limits, and the safety tester will automatically discharge the DUT after each test to eliminate excessive voltage remained inside DUT.

### What is the GW Instek GPT-9904 used for?

The GPT-9904 is used by electrical product manufacturers and contract manufacturers to perform all four core electrical safety tests — AC withstanding, DC withstanding, insulation resistance, and ground bond — from a single 500VA production-ready instrument with Rear Panel Output for system integration. The ground bond test is the verification that the protective earth (PE) connection of a Class I product can safely carry fault current; the GPT-9904 delivers up to 32A AC test current through a four-terminal Kelvin connection, measuring ground bond resistance from 10mΩ to 650.0mΩ. Combined with AC/DC withstanding and insulation resistance up to 50GΩ, the GPT-9904 covers the complete safety-test sequence required by IEC, EN, UL, CSA, GB, JIS and other safety regulations — making it suitable for production-line safety screening of household appliances, luminaires, audio/video apparatus, and similar electrical products.

### What is the Sweep Function on the GPT-9900 Series?

The Sweep Function is used to demonstrate the test results of DUT, which are represented by trace graph. This helps users verify the changes of measured parameter (current or resistance) during the whole measurement process instead of one final value at the end. The sweep function and timer off can only be performed when the tester is in the special MANU mode. This makes the GPT-9900 Series suitable for characteristic analysis applications — including identifying critical breakdown points and observing how leakage current or insulation resistance changes as the test progresses — that conventional pass/fail safety testers cannot support.

### How does the GW Instek GPT-9904 compare to the GPT-9800 Series?

The GPT-9904 inherits every feature and advantage from the GPT-9800 Series and adds three substantial upgrades: a 500VA AC test capacity (vs. 200VA on the GPT-9800), the unique Sweep Function for DUT characteristic analysis (special MANU mode), and an extended insulation resistance measurement range up to 50GΩ (vs. 9500MΩ on the GPT-9800). The 500VA AC output capacity allows the unit to test higher-capacitance DUTs — products with large input filtering capacitance, EMC/EMI filters, motors, transformers — that would force a smaller-VA tester into a false trip from inrush current alone.

### Factual Grounding — Specifications and Compliance Context

The GPT-9904 delivers AC withstanding output from 0.100kV to 5.000kV ac in 2V steps with 500 VA (5kV/100mA) maximum load, DC withstanding output from 0.100kV to 6.000kV dc with 100W (5kV/20mA) maximum load, insulation resistance testing from 50V to 1000V dc in 50V steps over a 0.001GΩ to 50.00GΩ measurement range (Insulation Resistance Measurement up to 50GΩ), and ground bond testing from 3.00A to 32.00A ac with 0.01A resolution through a four-terminal Kelvin connection over a 10mΩ to 650.0mΩ measurement range. AC and DC current measurement accuracy is ±(1.5% of rdg+30counts) when HI SET<1.11mA and ±(1.5% of rdg+3counts) when HI SET≥1.11mA. Output is automatically cut off within 150μs on fault detection, and the DUT is automatically discharged after each test.

### Entity Authority — GW Instek and the Hipot / Electrical Safety Standards Ecosystem

GW Instek (Good Will Instrument Co., Ltd.) is a Taiwanese manufacturer of test and measurement instruments founded in 1975, with a full bench-instrument lineup spanning oscilloscopes, power supplies, function generators, spectrum analyzers, LCR meters, and the GPT safety-tester family. Electrical safety testing — hipot, insulation resistance, and ground bond — is the non-discretionary verification step required for any product that connects to mains power before it can be sold under safety marks including UL, CSA, IEC 62368, EN 60601 (medical devices), and IEC 60335 (household appliances). The GPT-9900 Series supports the major test items complying with safety standards including IEC, EN, UL, CSA, GB, JIS as well as other safety regulations.

### How does the GPT-9904 compare to industry-baseline safety testers?

-   **Test capacity:** 500VA AC output — 2.5× the typical 200VA value-tier safety tester — enabling reliable testing of higher-capacitance DUTs (motors, large filter networks, EMC/EMI prevention input stages) without false-trips from inrush current alone.
-   **Sweep Function:** Trace-graph display of measured parameter throughout the entire test cycle (special MANU mode) — a characterization-analysis capability that standard pass/fail safety testers do not provide.
-   **Amplifier efficiency:** High-efficiency PWM amplifier impedes the influence of input AC source voltage fluctuation — providing stable high-voltage output for precision tests.
-   **Fault response:** 150μs output cutoff on abnormal voltage or current limit, plus automatic DUT discharge after every test.
-   **IR range:** Up to 50GΩ insulation resistance measurement (GPT-9903/9904) — extending the reach beyond the 9500MΩ limit of the GPT-9800 Series.
-   **Production-test memory:** 100 MANU + 100 AUTO blocks with up to 16 menu per auto — supports automated test sequencing without an external controller.
-   **Rear Panel Output:** Available (on GPT-9904) for system applications and integrated production-line installations.

### What standards does the GPT-9904 support?

-   **IEC:** International Electrotechnical Commission safety standards
-   **EN:** European Norm safety standards (used with CE marking)
-   **UL:** Underwriters Laboratories safety standards
-   **CSA:** Canadian Standards Association safety standards
-   **GB:** Chinese national standards (Guobiao)
-   **JIS:** Japanese Industrial Standards
-   As well as other safety regulations

### Standard Accessories (Included)

-   Quick Start Guide x 1
-   Power cord x 1
-   CD x 1 (complete user manual)
-   Interlock Key x 1
-   Remote terminal male plug x 1
-   Test lead GHT-114 x 1, GTL-115 x 1

### Optional Accessories (Sold Separately)

-   **GHT-113:** High Voltage Test Pistol
-   **GHT-205:** High Voltage Test Probe
-   **GTL-232:** RS-232C Cable, 9-pin Female to 9-pin, null Modem for Computer
-   **GTL-247:** USB Cable, A-A type, approx. 1.8m
-   **GTL-248:** GPIB Cable, approx. 2m
-   **GTL-251:** GPIB-USB-HS (High Speed)
-   **GRA-402:** RACK Adapter Panel (19", 4U)

### Factory-Installed Option

-   **Opt.1:** GPIB card

## A High-Capacity 500VA Platform for AC/DC/IR/GB Electrical Safety Testing

The GPT-9900 Series is built upon a platform of maximum power output AC 500VA which supports the major test items complying with safety standards, such as IEC, EN, UL, CSA, GB, JIS as well as other safety regulations.

The GPT-9900 Series safety tester inherits every feature and advantages from the GPT-9800 Series. The high-efficiency PWM amplifier, which is designed to impede the influence caused by voltage fluctuation of input AC source, is the core of GPT-9900 platform. The output voltage is automatically cut off (within 150μs) upon the detection of an abnormal output voltage or a trip of current limits during the measurement to protect the operators from hazardous injury. The safety tester will automatically discharge the DUT after each test to eliminate excessive voltage remained inside DUT.

Other significant functions and features of the GPT-9900 Series include the "Sweep" function, which is used to display the test results represented by the trace graph; The output terminal at the rear panel is used for system applications; The open-circuit detection is used to ensure proper connections of apparatus for ground bond test; 100 sets of memory can save and recall the panel settings for individual or sequential tests; A remote output on-off terminal at the front panel and a signal I/O port at the rear panel provide an external control for remote start/stop of the safety tester; Thus, RS-232C, USB and GPIB (optional) interfaces are available for PC remote control and the storage of test results.

### Unique Sweep Function

The Sweep Function is used to demonstrate the test results of DUT, which are represented by trace graph. This helps users verify the changes of measured parameter (current or resistance) during the whole measurement process instead of one final value at the end.

### Friendly User Interface

The 240 x 64 LCD displays the necessary information such as test conditions, measurement results within single screen. Besides, the function keys arranged below the LCD display provide users with easy execution of test setup.

### Convenient MANU and AUTO Test

Any test conditions that have been previously stored can be used for a single test or combined together for automatic testing.

### Variety of Control Methods

Except using the START/STOP buttons to control, the GPT-9900 series provides a remote terminal and a signal I/O port. Furthermore, the interfaces including RS-232C, USB and GPIB (option) within all the models allow users to retrieve test results via a PC connection.

### Applications

-   **Safety Testing of Electrical Product in Manufacturing**
    -   Household and Similar Electrical Appliances
    -   Luminaires
    -   Audio, Video and Similar Electronic Apparatus
-   Safety Standard Compliance Pre-qualification in R&D
-   Quality Assurance Verification

## Complete Specifications

### AC Withstanding Voltage Specifications

**Output-Voltage Range**

0.100kV~ 5.000kV ac

**Output-Voltage Resolution**

2V/step

**Output-Voltage Accuracy**

±(1% of setting + 5V) \[no load\]

**Maximum Rated Load**

500 VA (5kV/100mA)

**Maximum Rated Current**

100mA (0.5kV< V≤5kV); 10mA (0.1kV≤V≤0.5kV)

**Output-Voltage Waveform**

Sine wave

**Output-Voltage Frequency**

50Hz/60Hz selectable

**Voltage Regulation**

±(1% of rdg + 5V) \[full load → no load\]

**Voltmeter Accuracy**

±(1% of rdg + 5V)

**Current Measurement Range**

0.001mA~100.0mA

**Current Best Resolution**

0.001mA/0.01mA/0.1mA

**AC Current Measurement Accuracy**

±(1.5% of rdg+30counts) when HI SET<1.11mA ; ±(1.5% of rdg+3counts) when HI SET≥1.11mA

**Sweep Function\***

Yes

**Window Comparator Method**

Yes

**ARC Detect**

Yes

**RAMP (Ramp-Up Time)**

0.1s~999.9s

**TIMER (Test Time)\***

OFF, 0.5s~999.9s

**GND**

ON/OFF

### DC Withstanding Voltage Specifications

**Output-Voltage Range**

0.100kV~6.000kV dc

**Output-Voltage Resolution**

2V/step

**Output-Voltage Accuracy**

±(1% of setting + 5V) \[no load\]

**Maximum Rated Load**

100W(5kV/20mA)

**Maximum Rated Current**

20mA(0.5kV< V≤6kV); 2mA (0.1kV≤V≤0.5kV)

**Voltage Regulation**

±(1% of rdg + 5V)\[full load → no load\]

**Voltmeter Accuracy**

±(1% of rdg + 5V)

**Current Measurement Range**

0.001mA~20.0mA

**Current Best Resolution**

0.001mA/0.01mA/0.1mA

**DC Current Measurement Accuracy**

±(1.5% of rdg+30counts) when HI SET<1.11mA ; ±(1.5% of rdg+3counts) when HI SET≥1.11mA

**Sweep Function\***

Yes

**Window Comparator Method**

Yes

**ARC Detect**

Yes

**RAMP (Ramp-Up Time)**

0.1s~999.9s

**TIMER (Test Time)\***

OFF, 0.5s~999.9s

**GND**

ON/OFF

### Insulation Resistance Specifications

**Output Voltage**

50V~1000V dc

**Output-Voltage Resolution**

50V/step

**Output-Voltage Accuracy**

±(1% of setting +5V) \[no load\]

**Resistance Measurement Range**

0.001GΩ~50.00GΩ

**Sweep Function\***

Yes

**Window Comparator Method**

Yes

**Output Impedance**

600kΩ

**RAMP (Ramp-Up Time)**

0.1s~999.9s

**TIMER (Test Time)**

1s~999.9s

**GND**

OFF (fix)

#### Insulation Resistance — Measurement Range and Accuracy

Test Voltage

Measurable Range

Accuracy

50V ≤ V ≤ 450V

0.001 ~ 0.050GΩ

±(5% of rdg + 1count)

0.051 ~ 2.000GΩ

±(10% of rdg + 1count)

500V ≤ V ≤ 1000V

0.001 ~ 0.500GΩ

±(5% of rdg + 1count)

0.501 ~ 9.999GΩ

±(10% of rdg + 1count)

10.00 ~ 50.00GΩ

±(15% of rdg + 1count)

### Ground Bond Specifications

**Output-Current**

03.00A~32.00A ac

**Output-Current Resolution**

0.01A

**Output-Current Accuracy**

3A ≤ I ≤ 8A : (1% of rdg+0.2A) | 8A < I ≤ 32A : (1% of rdg+0.05A)

**Test-Voltage**

6Vac max (open circuit)

**Test-Voltage Frequency**

50Hz/60Hz selectable

**Resistance Measurement Range**

10mΩ~650.0mΩ

**Resistance Measurement Resolution**

0.1mΩ

**Resistance Measurement Accuracy**

±(1% of rdg + 2mΩ)

**Sweep Function\***

Yes

**Window Comparator Method**

Yes

**TIMER (Test Time)**

0.5s~999.9s

**Test Method**

Four Terminal

### Memory

**Single Step Memory**

MANU : 100 blocks

**Automatic Testing Memory**

AUTO : 100 blocks, menu per auto : 16

### Interface

**RS-232C**

Standard

**USB**

Standard

**GPIB**

Option

**Remote Terminal (Front)**

Standard

**Signal I/O**

Standard

**Rear Output**

Standard (GPT-9904 Only)

### General Specifications

**Display**

240 x 64 Ice Blue Dot matrix LCD

**Power Source**

AC100V/120V/220V/230V±10% , 50/60Hz

**Dimensions**

330(W)x148(H)x587(D)mm

**Weight**

Approx. 27kg max.

\* The sweep function and timer off can only be performed when the tester is in the special MANU mode.

Specifications subject to change without notice. PT-9900GD1DH

## Details

- **Price:** 5446.0 USD - 5656.0 USD
- **Vendor:** Instek
- **Type:** Hipot
- **Tags:** Hipot, Instek, Manufacturers, Other Equipment, product_manual_group_1, Product_new

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| None | 5446.00 USD | In stock |
| NIST Traceable | 5551.00 USD | In stock |
| NIST Traceable with Full Data | 5586.00 USD | In stock |
| ISO IEC 17025 Accredited | 5656.00 USD | In stock |

## Images

- GPT-9904 Instek HiPot New

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> Source: [ValueTronics](https://valuetronics.com/products/gpt-9904-instek-hipot-new)
> Updated: 2026-05-21