Megger mft help

[ezekiel]

been practising testing on a dummy board and all tests work out fine until:


measuring ze
efli
pfc

on all these tests MFT displays voltage but then get a TRP message in display - figure im doing something wrong with the procedure any ideas what?

 

[oharaf]

Which MFT is it Eze?

 

[ezekiel]

its 1552 - just cant see where im going wrong

 

[GaryMo]

You're not measuring on the no trip setting are you? This may or may not cause the problem you're having when using two leads.
Use two options at the far right hand side of the selector switch - Loop High and PFC if no RCD's are protecting your board.
Other than that, are your two leads in the correct terminals?

 

[oharaf]

Beat me to it GaryMo

Then again you'd know my MFT better than me

 

[ezekiel]

yeah the no trip is giving the error (why?)

just found hi setting will give you ohms for zs
and pfc gives ka for fault

does this require 3 leads or can it be done with 2?

circuits are rcd protected

 

[GaryMo]

If circuits are RCD protected then you'll need to use three wires on the no-trip setting for Zs.
Ze and PFC is generally carried out at the intake where no RCD protection exists so that will be two leads on the Hi current setting.

You're quite correct, Ze and Zs are measured in ohms and PFC is measured in kA.

 

[ezekiel]

thanks gary (had to turn electric back on again lol)

think i got it now
non trip and 3 leads for rcd side
hi settings and two leads for non rcd

actually getting readings now and kettle stays on - thanks v much

 

[GaryMo]

No problem at all, glad to help.