Megger 1553 - possibly damaged from PFC test

[AMC]

Hey, I have a Megger 1553 and lent it to a friend, who is an experienced spark with 2391 and good knowledge/experience of testing. However, friend carried out PFC test using 3 leads, even though PFC should be carried out using 2 leads on this unit. Since PFC was carried out incorrectly the tester will apparently now only detect reversed polarity when trying to carry out any Zs or RCD tests. She tried 2no different socket test leads and separate leads with kewtech R1+R2 socket but still no joy. Recently calibrated, batteries replaced, and replacable fuse is fine. Anyone had a similar problem? I havent got the unit back of my friend yet and am just trying to work out and whether its completely dead from doing the test wrong or just an internal fuse that has blown? Thanks

 

[MarkieSparkie]

Hi AMC, The Megger 1553 MFT can test PFC in two configurations:
1) "PFC Hi" a 2 lead high current test, which doesn't actually measure and indicate PFC, but either PSCC (line to line) or PEFC (line to earth) depending on the lead connections.
2) "No-trip PFC" a three lead test, a combined low current line to earth/high current line to line test, which does measure and indicate PFC directly.
A 3 lead test method therefore should not have resulted in damage to your MFT, assuming that the maximum 500V line to line and 300V line to earth ratings are not exceeded.
As your friend has tried alternative test lead sets, it seems unlikely that the indicated reverse polarity is due to a continuity problem with the test leads. So, IMO the most likely causes are, either the installation being tested actually is reverse polarity, or your friend is misinterpreting the MFTs polarity indicators, which at best are for guidance only and may not necessarily indicate the true polarity in all circumstances e.g. their indication is invalid when using the 2 lead test method, or the MFT does indeed have internal fault.
A live polarity test on the installation (and maybe a known installation for comparison) with an approved 2 pole voltage indicator and the MFT on the voltage "V" range, should determine if the indicated "reverse polarity" is real installation condition or an MFT fault.

 

[AMC]

Hi MarkieSparkie,

thanks for your reply, yeah I believe she had it set on 'PFC Hi' But used 3 leads and whacked it across Live/Neutral/earth, when like you say it should be done Line to line or line to earth. She was dong the tests in her own house where no work had been carried out in preparation for NIC assessment, we know polarity on the install itself is fine. As soon as you connect the tester using the socket tester lead it starts going mad and beeping saying reverse polarity. Im thnking it didnt like the 3 lead test on 'PFC Hi' Damn!