metrel mi3100s help

[electrified]

Slight confusion with this tester. when you do a zs it asks for the brown and green to be connected and has the half sign to show that the neutral would be better to connect, obviously connecting this would be better for the rcd zs?

anyways when doing ze, do i have to connect the neutral as it would just be dangling there, i’ve seen something about connecting it to the earth by piggybacking it but i’m not sure if this would effect the reading. Also there is a LINE option which measures L-L or L-N, this is PFC, so i was wondering if i could use this setting to measure ze as it is there same principle of measuring the impedance, i would connect brown to Line and blue to earth.

Thanks

 

[chivers67]

I'm not totally familiar with your Meter but most MFTs should have a 2 high option which measures ZE/ZS with the two Phase and Earth leads and also perhaps a 3 low option to measure ZS using three leads Phase Neutral and Earth so an upstream RCD is not tripped.

 

[electrified]

I'm not totally familiar with your Meter but most MFTs should have a 2 high option which measures ZE/ZS with the two Phase and Earth leads and also perhaps a 3 low option to measure ZS using three leads Phase Neutral and Earth so an upstream RCD is not tripped.

problem is that the 3 leads that come with the tester are all in one block that has to be connected to the meter all at once, it’s not like a normal one where you can plug in brown and green if you want. I’m guessing it is better to use the neutral in a zs to prevent tripping the rcd, but when doing the ze you want to put the brown onto Line and Green onto the main earth. this then means that there is a neutral that needs to be connected somewhere or let it dangle which i’m confused about.
I appreciate your reply thanks.

 

[EFLImpudence]

Here is the manual for SE model - can't find just S.

https://www.metrel.si/assets/Metrel...100_s_EurotestEASI_Ang_Ver_1.1_20_752_131.pdf

I am not familiar with the Metrel either but it looks like you have to connect all three leads and the different tests are selected on the meter.

 

[ajstoneservices]

I have the metrel 3000I. ZE and ZS are 3 lead tests.

 

[Adam_151]

The only issue with piggybacking it onto the earth is that it will then use the supply from Brown->blue to draw a small amount of current to do whatever it needs to do, not a lot and not normally a problem but not that when its putting a test current down the earth it limits duration and also tries to watch for a voltage collaspe that would signify an open earth in order that in case of an open earth, the tester doen't create too much of a danger, it is not likely to be doing this with what it thinks is a neutral return to power itself.

So you can do this as long as you are aware that it would be not good to be doing it if the earth proved to be open, so likely less risk of if using in this way to take Zdb than at the end of lighting cirucits for instance.

Or at least thats how it used to be with the earlier models* that did always want three leads connected, you could stack N/E for none rcd supplies but probably wasn't a great thing to do unless you were sure that your earth path was existant, there is probably a bit more protetcion built into the version you have as you wouldn't expect to have a dangerous voltage on the hanging N, so it must do at least some sensing that it is safe to power instrument in this way- but how much... not sure

I would regard using the Zline function as a Zloop to be much the same outcome, it'll still attempt to power instrucment between Brown/Blue (might even do less checks) but will just have moved to the lead its measuring onto to blue instead of green as well

In a high current mode (Zloop, not ZRCD) on a tester that only insists on 2 leads, the reading is not likely to differ much between having blue connected/not connected.

*Used one of these https://www.google.com/search?q=metrel+easitest upto about 10 years ago. Its still in the garage somewhere! You would only get one decimal place on loop testing on RCD protected cirucits (e.g. just 0.3) which arguebly didn't matter that much, just looked a bit odd on the paperwork!

 

[electrified]

thank you very much this forum is the only one to actually reply. I have usually seen the brown and green 2 lead to do ze on meter etc, so i was confused when i saw this. and i will have to put the blue lead onto the live neutral on the dp switch not the neutral bar?
and you think this will not make a difference to the reading? as long as you are sure i will use 3 lead every time

Thanks