Megger Loop Impedance Tester LTW315-EU-BS

Earth loop impedance testers to verify the loop impedance of a live electrical circuit without the need to disconnect the electrical supply. The LTW300 series instruments offer a safe and easy 2 wire loop testing solution that does not trip 30mA RCDs and can be used on a wide range of voltages.

The new LTW300’s offer a range of features to make earth loop testing safer and easier.

The range consists of:

• LTW315 - 2 Wire loop impedance measurement
• LTW325 - 2 wire + maxZ + (R1+R2)
• LTW335 - 2 wire + maxZ + (R1+R2) + Download
• LTW425 - 2 wire + maxZ + (R1+R2) + 0.001 Ω

2 Wire testing

A loop test is performed with only 2 test leads. This can be either:

• Phase to Earth
• Phase to Neutral
• Phase to Phase

Testing is simple, as there is no need for a 3rd wire to be connected, which can cause confusion when trying to identify which part of the circuit is being tested. Test results are displayed to a resolution of 0.01 Ω.

Non-trip loop testing

The LTW300 series are guaranteed not to trip working RCDs of ≥30 mA, using the No-trip loop test. 3 Phase circuits with RCD protection can also be tested, as all test modes operate on single and three phase systems. The loop test runs for approximately 10 seconds, with an additional 10 seconds if the instrument detects electrical noise on the supply that could otherwise cause errors on the test result.

High current loop testing

For supplies that do not have an RCD fitted the high current test should be used, as there is no risk of tripping and RCD.

Noise detection (only applies to No-trip tests)

The LTW uses sophisticated noise detection circuitry which continually monitors the supply whilst performing a loop test to ensure the accuracy of the result has not been compromised by the effects of electrical noise from plant and services. Two operational modes are available: a) 10 second test: Always performs a 10s test and if noise is detected displays a warning at the end of the test b) Auto test extension Automatically extends a test up to a further 10 seconds if noise is detected, to improve the accuracy of the test.

AUTO START

An auto-start function will start the loop test running as soon as the test leads are connected. No need to press the test button means much safer testing.

Operating voltage

The instruments will operate on a wide range of electrical voltages (see table below) from 50 V a.c to 300 V a.c single phase supplies and up to 440 V a.c on 3 phase installations. These include centre tapped 110 V a.c circuits, with 55 V phase to earth. LTW315 is limited between 100 V – 280V

Includes :

• BS1363 to 3 x 4 mm socket leadset
• 2 wire leadset with croc clips
• Plug test lead
• Hard carry case
• User CD