Naughty Megger Mft1720

[Dal Roberts]

2 wire phase and earth trips mcb when looping at lights, if i reverse no trip and successful loop reading i.e.: Phase / earth connected on megger as normal colour co ordinated leads to points on megger, then only way to not trip mcb is to (at the lighting point) put phase lead from megger to earth and earth lead to phase at light, if i test per phase correct it trips , anyone else experiencing this on the MFT1720 

http://uk.megger.com/support/faqs/loop-testing/

on megger support says clearly 2-wire test At a light switch a neutral is usually not available so a 2-wire test is easier for testers without 3 hands

 

[dmxr]

If it's 6A, doing Zs with 2 leads (high current) most testers will trip it out. Use 3 leads.

 

[Andy™]

If it's 6A, doing Zs with 2 leads (high current) most testers will trip it out. Use 3 leads.

kind of defeats the point in having a 2 lead test so that it will work on a light switch with no neutral...

 

[Sidewinder]

I didn't think the Megger 17xx series does 3 wire loop tests?

Not looked at the manuals mind, my LTW425 only does a 2 wire non trip test, & that does not trip 30mA when connected conventionally.

 

[dmxr]

I didn't think the Megger 17xx series does 3 wire loop tests?

Not looked at the manuals mind, my LTW425 only does a 2 wire non trip test, & that does not trip 30mA when connected conventionally.

My 1720 does 2 high and 3 low

kind of defeats the point in having a 2 lead test so that it will work on a light switch with no neutral...

Agreed

 

[apprentice87]

My 1730 does high and low, only uses two wires, and works perfectly. Try reading the makers manual.......

Different lead setup for the high current test..... You are doing it wrong......

john...

 

[steptoe]

its a megger,  :slap

how could he possibly be doing it right?  :slap

 

[kerching]

Surely it is no fluke?

Just saying

 

[Blue Duck]

ze or not ze that is the question.

 

[kerching]

ze or not ze that is the question.

You know what will happen now that you have invoked the incantation!

Say Beetljuice thrice and....well, you know the rest

 

[pewter]

My 1730 does high and low, only uses two wires, and works perfectly. Try reading the makers manual.......

Different lead setup for the high current test..... You are doing it wrong......

john...

My 1730 used to be 2 wire only, after one of the software updates it was 2 or 3 wire.  before the 3 wire update i had to reverse L + E (under Meggers instruction)  to stop tripping some RCDs.  I should check to see if there is a manual for my version.

 

[ISSWWW]

2 wire phase and earth trips mcb when looping at lights, if i reverse no trip and successful loop reading i.e.: Phase / earth connected on megger as normal colour co ordinated leads to points on megger, then only way to not trip mcb is to (at the lighting point) put phase lead from megger to earth and earth lead to phase at light, if i test per phase correct it trips , anyone else experiencing this on the MFT1720 

http://uk.megger.com/support/faqs/loop-testing/

on megger support says clearly 2-wire test At a light switch a neutral is usually not available so a 2-wire test is easier for testers without 3 hands

Can you remember the make of MCB?

 

[ISSWWW]

If the Instruments test current is DC and the MCB's coil is wound the other way around, as some are, then swapping the leads out will allow the test to be completed.

The manufacturers do not give details of the test current in general but i assume Megger must use DC.

 

[Dal Roberts]

Can you remember the make of MCB?

RCBO 6 Wylex maybe thats why , may have to disconnect neutral and earth flys? 

 

[dmxr]

My 1730 does high and low, only uses two wires, and works perfectly. Try reading the makers manual.......

Different lead setup for the high current test..... You are doing it wrong......

john...

Mine does 2 low/2 high and 3 low. 

2 high will trip a 6A RCBO , my old robin tester used to drop out a 10a MCB on test.