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Extech
Extech GRT300 4-Wire Earth Ground Resistance Tester
Quote on request
No online payment · add lines to RFQ BOM
2/3/4-wire ground; 2–2000 Ω; CAT IV 300 V; kit. RFQ + selection help.
Download datasheet PDF
RFQ cart holds BOM lines only. Submit for engineering quote.
Key parameters
Accuracy
±(2% of reading + 3 digits)
Supply
Eight 1.5 V AA batteries
Earth Resistance Ranges
2 Ω / 20 Ω / 200 Ω / 2000 Ω
Resolution
0.01 Ω / 0.1 Ω / 1 Ω / 0.01 kΩ
Test Current Frequency
<2 mA / 820 Hz
Earth Voltage
0 to 300 VAC (40–500 Hz); ±(2%rdg + 3d)
Fits stake-method earth ground testing where you need an Extech GRT300 with 2/3/4-wire modes covering 2–2000 Ω, earth voltage to 300 VAC, and CAT IV 300 V safety in a complete kit.
Key advantages
- Ranges — 2 / 20 / 200 / 2000 Ω
- Accuracy — ±(2% of reading + 3 digits)
- Modes — 2-wire, 3-wire, and 4-wire testing
- Earth voltage — 0–300 VAC; test <2 mA @ 820 Hz
- Kit — Leads, 4 earth bars, hard case, 8× AA; CAT IV 300 V
Typical applications
- Facility earth electrode testing.
- 3- and 4-wire fall-of-potential checks.
- Earth voltage presence checks.
Selection guide
- 2/3/4-wire — Method needed
- Spike spacing — 5–10 m typical
- Kit accessories — Bars/leads
- CAT IV — Outdoor electrode work
Common mistakes
- Testing with earth voltage >10 V uncorrected.
- Twisted/adjacent leads causing coupling.
- Wrong wire mode for setup.
When to RFQ / what to tell us
- NIST option if needed; quantity; ship-to.
Request a Quote · Get selection help
Specs
| Spec | Value |
|---|---|
| SKU | 31304 |
| Brand | Extech |
| Model | GRT300 |
| Product type | Ground Resistance Tester |
| Type | 4-wire earth ground resistance tester (2/3/4-wire) |
| Resistance ranges | 2 Ω / 20 Ω / 200 Ω / 2000 Ω |
| Accuracy | ±(2% of reading + 3 digits) |
| Resolution | 0.01 Ω / 0.1 Ω / 1 Ω / 0.01 kΩ |
| Earth voltage | 0–300 VAC (40–500 Hz) |
| Test | Test current <2 mA; frequency 820 Hz |
| Safety | CAT IV 300 V |
| Power | 8× AA; ~250×190×110 mm; ~1430 g |
| Kit | Leads with alligator clips, 4 earth bars, hard case |
Documents
FAQ
Q: Ranges? A: 2 Ω / 20 Ω / 200 Ω / 2000 Ω.
Q: Wire modes? A: 2-wire, 3-wire, and 4-wire.
Q: What should I send for a quote? A: Options, quantity, ship-to.
Links
| Parameter | Value |
|---|---|
| Accuracy | ±(2% of reading + 3 digits) |
| Supply | Eight 1.5 V AA batteries |
| Earth Resistance Ranges | 2 Ω / 20 Ω / 200 Ω / 2000 Ω |
| Resolution | 0.01 Ω / 0.1 Ω / 1 Ω / 0.01 kΩ |
| Test Current Frequency | <2 mA / 820 Hz |
| Earth Voltage | 0 to 300 VAC (40–500 Hz); ±(2%rdg + 3d) |
| Test Modes | 2-wire, 3-wire, and 4-wire earth resistance; automatic I/P spike check |
| Safety Category | CAT IV 300 V |
| Form Factor | 9.8 × 7.8 × 4.3 in (250 × 190 × 110 mm); 3.15 lb (1430 g) |
| Included | Test leads with alligator clips, 4 earth bars, hard case, batteries |
| Family | Extech GRT300 |