Help!!!! Metrel Mi3000 tester problem

[junior-sparky]

Finshed and install in an unoccupied building today and went to do the testing and my meter decides to play up.

I always like to do my RCD test first (nothnig like the sound of the click to know it's working) but upon the auto teest at 30ma it stops at x1. another issues is the RCD would trip when trying to do a zs of the 2 rings (set to test with RCD).

I have a shiney new house and tried the 2 tests on my board and exactly the same issue!!!

Has anyone else had experience of this and is my meter dead or an easy fix?

I should add that i used both the 3 pin plug lead as well as the kewtech 3 pin adaptor but same issue.

It was only recently caliberated ..

cheers

 

[Deleted member 26818]

What type are the RCDs?

 

[amlu]

best contacting Metrel directly. your meter is certainly not dead, it maybe just some simple patch on firmware or something like that. They all microprocessor controlled this days.

 

[amlu]

side note: testing rcd first at the beginning is useless, it may not operate correctly when there is messed up wiring (insulation resistance, continuity) or some faults with the earthing system (Ze!)

 

[junior-sparky]

Its an MK board, 2 rings (1fcu spur for security light), 2 lights

 

[stevethesparks]

Try removing the batteries for about 10 seconds, and try again. Obviously make sure that settings have not been altered and that the "G" appears in the type section of the window and is also set to 30mA - these things can be easily overlooked if altered accidentally.

 

[hightower]

I've a video on the forum somewhere of updating the firmware yourself if you don't want to send off. It does have the disclaimer that it is possible to brick the tester if something goes wrong though.

 

[Deleted member 26818]

The Metrel Mi3000, I believe will only test type A RCDs.
I don't think it will test type B RCDs.
What type of RCDs are you attempting to test?

 

[a-z electrics]

The Metrel Mi3000, I believe will only test type A RCDs.
I don't think it will test type B RCDs.
What type of RCDs are you attempting to test?

Tosh! The mi3000 tests type B no problem..
Are you sure the "rings" are definitely ring circuits? Also try the trip test on another circuit eg cooker, or lights. You need to do all other tests first really because there may be all sorts of problems with the circuits.

 

[davesparks]

Tosh! The mi3000 tests type B no problem..
Are you sure the "rings" are definitely ring circuits? Also try the trip test on another circuit eg cooker, or lights. You need to do all other tests first really because there may be all sorts of problems with the circuits.

According to the manual it is only intended to test type AC and A, not type B. So it cannot be relied upon to test a type B RCD correctly.

 

[Deleted member 26818]

My name's not Tosh?

 

[a-z electrics]

Well I stand to be corrected as I dont have a full manual (the quick guide doesn't mention it) but I have never had trouble testing type B RCDs.
How would the type affect the earth leakage trip though?

 

[davesparks]

Well I stand to be corrected as I dont have a full manual (the quick guide doesn't mention it) but I have never had trouble testing type B RCDs.
How would the type affect the earth leakage trip though?

It's not an earth leakage trip, it's a residual current trip.
The type denotes the various types of residual current that the RCD will operate with. type B RCDs are designed to cope with residual currents with a DC component, and will need testing differently to a type AC RCD. Whilst it will trip on a normal RCD test you will not be testing it properly.

The fact that a type B RCD is designed to ignore DC currents might explain why it trips on an non-trip loop test since testers use DC to saturate the coil of a normal RCD to prevent it tripping.

 

[a-z electrics]

It's not an earth leakage trip, it's a residual current trip.
The type denotes the various types of residual current that the RCD will operate with. type B RCDs are designed to cope with residual currents with a DC component, and will need testing differently to a type AC RCD. Whilst it will trip on a normal RCD test you will not be testing it properly.

The fact that a type B RCD is designed to ignore DC currents might explain why it trips on an non-trip loop test since testers use DC to saturate the coil of a normal RCD to prevent it tripping.

OK thanks for that.. I'm getting confused with the type B fuse curve, as in a type B rcbo.
I've found the full Metrel manual now and it doesn't actually mention type B, just type AC (sine wave) and type A (dc pulse) which are the test currents. It only differentiates between two types of RCD to test - G (general) and S (delayed). I've just checked a control gear RCD and the leaflet states its for AC or A. So I don't know what a type B RCD is then? Either way, a domestic RCD will surely be an AC but I can understand now why the question was asked..
Wishing all on the forum a very Merry Christmas!

 

[davesparks]

AC and A are the types of the RCD that it can test, the other type being B
Type B RCDs are rarely required and rather expensive, and most multifunction testers don't cater for them.
I've been looking at megger recently with a view to replace my mft and the only one which does type B RCD is the top of the range one (which I have no need for)

 

[Deleted member 26818]

Type B RCBOs are used where there is PV.
So they will become more common place, as more homes get PV.
I believe also, that they are required for vehicle charging points?

 

[davesparks]

They are only required when the DC residual current component exceeds a certain value (6mA springs to mind)
If the PV equipment or charging unit has built in protection to prevent a DC residual current then a type A RCD is ok.

And that's the extent of my knowledge on these areas so can't go in to any more detail