LT300 High Current Loop Impedance Tester

LT300 High Current Loop Impedance Tester.

The Megger LT300 delivers high-current line / earth loop testing over a wide range of frequencies and supply voltages with simple, fast, two-wire operation. The instrument auto-detects supply frequency on connection — 16 Hz, 50/60 Hz, or 400 Hz — and starts testing automatically. A large clear LCD aids visibility in poor lighting.

Two loop-impedance ranges are provided: 20 Ω with 0.01 Ω resolution and 200 Ω with 0.1 Ω resolution. Loop test current reaches 27 A on the 20 Ω range at 550 V (12 A at 230 V, 6 A at 115 V), giving fast and stable results across the full operational supply range of 50–550 V (400 V at 16 Hz). Loop resistance accuracy is ±5%.

CAT IV 300 V phase-to-earth (or 550 V phase-to-phase, IEC 61010-1). A high-voltage warning is generated above 330 V to flag accidental phase-to-phase connections on a nominal 230 V system. Housed in a rubber-armoured case with a built-in cover that protects the display when stowed; IP54 weatherproof. Operating range −10 °C to +60 °C.

The LT300 series ships in three lead-set configurations:

• LT300-EN-00 (this product) — two-wire red/green lead set with crocodile clips

• LT300-EN-BS — BS1363 mains-plug test lead for direct socket access

• LT300-EN-FS — fused red/green lead set (10 A) for added safety on uncertain installations

Powered by 8 × AA (LR6) alkaline or NiMH rechargeable cells. Complies with EN 61557 Parts 1 and 3 (loop resistance) and IEC 61326-1 EMC. Weight 980 g (2.16 lb); dimensions 203 × 148 × 78 mm (8 × 5.8 × 3 in). Supplied with a hard carry case and certificate of test.

The Megger LT300 High Current Loop Impedance Tester # LT300-EN-00 is manufactured by Megger. Valley Instrument Service is an authorized Megger dealer offering full sales support, NIST-traceable calibration, and expert technical assistance.