Be the first to review this product

LT300 High Current Loop Tester (with red/green leads)

The Megger LT300 High current loop testers offers testing over a wide range of frequencies & supply voltages with simple, fast, two wire operation. It has a large clear display that aids visibility in poor conditions.

Part Number:

read more


Product Options

List Price

546.00 incl. VAT)
Add To Cart




Megger LT300 High Current Loop Tester

A high current loop tester that is ideal for industrial applications with 50 V to 500 V and 16 Hz to 400 Hz operational range.  Megger LT300 offers users the assurance of a CAT IV rating.

Housed in a rubber armoured case with a built-in cover to protect the display when not in use.  The IP54 weatherproof rating provides excellent protection in adverse conditions.  It has a large clear display that aids visibility in poor conditions.

The LT300 offers high current loop testing over a wide range of frequencies and supply voltages with simple, fast, two wire operation.

The high current loop test provides fast accurate and stable results with a resolution to 0.01 Ω on the 20 Ω range.

Frequency range: Supply frequency is indicated upon connection to the supply. This will automatically set to the measured supply frequency either 16 Hz, 50/60 Hz or 400 Hz. Testing will commence automatically.

Loop Impedance measurement:

  • Two loop impedance ranges are provided
  • 20 Ω - Resolution to 0.01 Ω
  • 200 Ω - Resolution to 0.1 Ω

Supply voltage: Operational  supply  range  extends  from  50  V  to  550  V  (400 V @ 16 Hz), with a warning for voltages over 330 V highlighting accidental phase to phase connections on a nominal 230 V system.Single Phase CATIV 300 V phase to earth, as well as 550 V phase to phase applications (400 V @ 16 Hz).

Megger LT300 Key Features:

  • CAT IV 300V applications
  • High current loop tester
  • Single and 3 phase testing
  • 16 Hz to 400 Hz operation
  • Two wire lead set or mains plug leads

The various models of the LT300:

The instrument is supplied with either a two wire (red/green) lead set, or a mains plug test lead for access to wall sockets, a certificate of test and a hard carry case.

  • LT300-EN-00 - with red/green leads
  • LT300-EN-BS - with BS1363 mains plug lead
  • LT300-EN-FS - with fused red/green leads



Technical Specification for: Megger LT300 High Current Loop Tester (with red/green leads)

Voltage Measurement Range0V to 550V (400V @ 16Hz)
Voltage Accuracy±5% ± 2V
Loop Test Operating Frequencies 16Hz - 15Hz to 18Hz, 29Hz to 337Hz
50/60Hz - 40Hz to 70Hz, 125Hz, 100Hz to 142Hz
400Hz - 260Hz to 498Hz
Test Currents550V: 20Ω - 27A, 200Ω - 2.7A
230V: 12Ω - 12A, 200Ω - 1.2A
115V: 20Ω - 6A, 200Ω - 0.6A
50V: 20Ω - 3A, 200Ω - 0.3A
Loop Test Accuracy0 to 19.99Ω (20Ω range) - ±5% ±0.03Ω
0 to 199.9Ω (200Ω range) - ±5% ± 0.5Ω
Operating Temperature-10 to 60°C
Storage Temperature-25 to 70°C
Humidity90% RH @ 40°C
Maximum Altitude2000m
Dust and WaterIP54
Battery8 x AA (LR6) Alkaline or NiMH Rechargable Cells
SafetyMeets the requirements of IEC61010-1 300V CAT IV
Phase to Earth or 550V Phase to Phase (400V@16Hz) 
EN61557Complies with the following parts of EN61577:
 Electrical Safety in Low Voltage Systems up to 1000V AC 
and 1500V DC, Equipment for Testing, Measuring or
Montioring of Protective Measures:
Part 1 - General Requirements
Part 3 - Loop Resistance
EMCIn accordance with IEC61326-1
Weight980gms (2.6lb)
Dimensions203 x 148 x 78mm (8 x 5.8 x 3in)
Product Downloads


Accessory Code Description Price (Ex VAT)
1000-562 Probe Cap [clear] bag of 20 £23.00 ADD
1001-883 Test Lead Set 3- wire Red/Black/Green with prods/clips (Special plug) £57.00 ADD
1004-323 SIA10 Socket Interface Adaptor UK to 3 Leads x 4mm price on request
1007-003 Blow Moulded Case Catch (Pack of 10) £17.00 ADD
1007-167 Blow Moulded Case MIT300 Series/LT/RCDT £22.00 ADD
6231-601 UK Mains Plug Leadset £21.00 ADD