Metrel Eurotest Mi3100. Low ohms problems

[Sad Anorak]

I have a metrel MI3000 and before each testing session I do a hard reset by switching off, removing leads, selecting 'phase rotation'. Then pressing the RH select key (next to the test button) whilst pressing 'on'. This seems to correct any wayward low ohms readings. Also after this sequence you can press 'CAL' whilst nulling leads.

 

[Farmelectrics]

Personally I think the metrels are good had mine 7 years and still happy with it so there lol

 

[roukel01]

Just as an update... I'm on my 3rd Eurotest Easi in just shy of 4 years! It failed its calibration yet again this year, Metrel wanted £170 to repair, so I found the managing directors email address out online and sent him an email explaining my issues. They repaired it for free!
I've not had one year where these testers haven't cause me trouble.

 

[Sad Anorak]

I've gone through two in three years, but I accidentally overloaded the first one causing continuity not to work anymore. I'm not entirely happy with the second one as it doesn't always read loop resistance first time (F1 symbol comes up but F1 fuse is always OK). If I leave it for half an hour or so and hard reset it, it checks OK. I find this disconcerting as it is needed for the cert plus during estimates. Continuity can be fickle as I described. It only sends out 8.5ma - a very low current for that test so can be reading high unless an excellent connection.

 

[Deleted member 26818]

To Null the leads, connect the two leads together, press the 'test' button, then press and hold the 'CAL' button until 'Co' appears on the screen.
To remove the Null, disconnect the leads, press the 'test' button, then press and hold the 'CAL' button untill 'Co' disappears
If you get inconsistant readings, you could try adjusting the 'high resistance' limit.
Or switch to continuity instead.

 

[dodge26]

Never had any problems with the Metrel, think it is a good standard of tester, and is good value for money.

 

[MarkieSparkie]

...Continuity can be fickle as I described. It only sends out 8.5ma - a very low current for that test so can be reading high unless an excellent connection.

If this is true, then you have a serious problem on your hands mate. Your tester has NOT been testing to BS7671:2008+A1:2011 612.2.1 which requires a low resistance ohmmeter to have a no-load voltage 4-24V dc or ac and a short-circuit current of not less than 200mA.

This has profound implications, as every certificate you have issued whilst using a faulty tester is now effectively invalid. Your registration scheme may require that you to retest every installation that you have tested with this faulty instrument since it's last calibration.

This clearly demonstrates why every electrician needs a comprehensive periodic comparative checking routine and certainly beyond that which the simple check-boxs, Cal-cards or a hand full of resistors can provide. That way deviation from the calibrated norm is noted and any trend beyond the requirements BS7671, BS EN 61577 or the manufacturer's specification lead to early diagnosis, recalibration and/or repair.

 

[Sad Anorak]

My fully calibrated and regularly verified Metrel installation tester isn't faulty, and I only quote the manufacturer's specification. I use the low resistance range for recording readings on my certs. This range delivers a minimum 200mA at 6.5 to 9v DC. Therefore fully conforming with requirements of BS7671 that you quoted. However the continuity range, used for basic checking whether a connection exists or to help fault finding, only delivers 8.5mA at the same voltage. I wouldn't use it otherwise. Please don't assume I don't have a checking regime or regular calibration check in place or that I wouldn't care if my meter was not reading correctly.