Instructions

3
Contents
Introduction 4
General introduction 5
Unpacking the carton 5
LCD display 6
Top panels 7
Additional controls on the LTW335 8
Keypad controls 8
Range knob controls 8
Connection panel 9
Lid open/closure 9
Preparations for use 10
Preliminary test lead 10
Ingress moisture 10
General operating instructions 10
Backlight operation 10
Test leads 10
Test lead connection 11
Loop testing 12
Description of test methods 12
No-trip test (all instruments) 12
Symbols used during a normal loop test 12
High current test (all instruments) 13
High resolution test (LTW425 only) 13
Performing a loop test 13
Non-tripping loop test (NO TRIP) 13
No-trip testing using the mains socket test lead 13
Phase to Earth loop test 13
Phase to Neutral loop test 13
No-trip loop testing using the RED/GREEN test lead 14
Phase to Earth loop test 14
Phase to Neutral and Phase to Phase loop testing 14
Earth bonded metalwork testing 14
High current loop test 14
High current Phase to Neutral loop test 14
High current Phase to Phase loop test 15
High resolution loop test (LTW425 only) 15
Prospective fault current display (PFC) 15
PFC measurement 15
Possible source of error 15
MaxZ (LTW325, LTW335 and LTW425) 16
Diriving R1 + R2 (LTW325, LTW335 and LTW425) 16
Measuring Zref 16
Voltage and frequency measurement 17
Phase to Earth and Phase to Neutral voltage and frequency measurement 17
Phase to Phase voltage and frequency measurement 17
Saving and downloading test results (LTW335 only) 18
Storing LOOP test results 18
To store a result 18
To store subsequent result 18
To recall test result 18
Downloading results to a PC 19
Deleting test results 19
SETUP menu 20
Setup option selection 20
Fused or long test lead length 20
Backlight brightness adjust 21
Warning and status messages 22
Loop test inhibit or premature termination of a loop test 22
Replacing batteries and fuses 23
Low battery warning symbol 23
Procedure to replace batteries 24
Fuse blown indicator 24
Auto power down 24
Preventative maintenance 24
Technical specification 25
Accessories 26
Repair and Warranty 27