Datasheet

ManualsBrandsMegger ManualsTest EquipmentMegger;LTW425Loop impedance measuring device; measurements according to DIN VDE 0100-600, DIN VDE 0105-100

LTW 300 series

2 Wire Loop impedance testers

DESCRIPTION

The new Megger two wire earth loop testers verify the loop

impedance of a live electrical circuit, ie without the need to

disconnect the electrical supply. The new LTW300 series

instruments offer a 2 wire loop testing solution that does

not trip 30 mA 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:

n LTW315 - 2 Wire loop impedance measurement

n LTW325 - 2 wire + maxZ + (R1+R2)

n LTW335 - 2 wire + maxZ + (R1+R2) + Download

n 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:

n Phase to Earth

n Phase to Neutral

n 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

n 2 Wire Non-tripping loop tester

n 50 V to 440 V operation

n 110 V centre-tap loop testing

n CATIV installation testing

n AUTO start - operation

n 0.001 Ω resolution (LTW425)

LTW300

2 Wire loop impedance testers

Summary of content (4 pages)

PAGE 1
LTW300 2 Wire loop impedance testers LTW 300 series 2 Wire Loop impedance testers n 2 Wire Non-tripping loop tester n 50 V to 440 V operation n 110 V centre-tap loop testing n CATIV installation testing n AUTO start - operation n 0.001 Ω resolution (LTW425) DESCRIPTION Test results are displayed to a resolution of 0.01 Ω. The new Megger two wire earth loop testers verify the loop impedance of a live electrical circuit, ie without the need to disconnect the electrical supply.
PAGE 2
LTW300 2 Wire loop impedance testers 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. to earth or 440 V phase to phase can safely be tested. 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.
PAGE 3
LTW300 2 Wire loop impedance testers LTW315 LTW325 LTW335 LTW425 NO-TRIP Loop and High current Loop test Source voltage: Features LTW315 100V to 280V (49Hz to 50.1Hz) LTW325,335 & 425 50V to 440V Display range: 0.01 Ω to 2000 Ω (49Hz to 50.
PAGE 4
LTW300 2 Wire loop impedance testers Mechanical Weight: Dimensions: 1000g ±10% excluding test leads 203 x 148 x 78 mm Patents The loop testing technologies used in these instruments are subject to the following patent applications: UK Patent no. 0518089.9 European Patent no. 06119110.2 US and Canadian patent application.