Electrics tripping.

[M77]

Hi there does anyone have an idea why electrics would trip if I put my multimeter between live and earth?

 

[Dotty]

Faulty multimeter, sensitive rcd.

 

[M77]

Thanks croppie, do you know if this is an easy fix or is it a right off? It's a fluke 116?

 

[stani]

First thing to find out. Is it tripping the RCD or an mcb, if its tripping the mcb then it's a fault, if its tripping the RCd then all multi meters will do that, because you are creating a direct short to earth.

 

[Dotty]

Not all multimeters, there are ones on the market that are designed to test rcd protected circuits. Would've thought fluke was one of them tbh.

Try your multimeter on a different working circuit protected by an rcd and see if the same thing happens.

 

[M77]

All multimeters will trip electrics between live and earth?? If its tripping the mcb then do you mean it's an electrical fault?
So your saying if the circuit is rcd protected my multimeter will trip electrics?

 

[erj]

i have mine do that, as Stani says probley rcd, but us been gas men never too sure of the which is which

 

[Crinkmeister]

What range were you using it on - Auto LZ or AC voltage? Apparently, the auto range is a low impedance input (doesn't say how low), so that might trip the RCD on its own - it only needs 30mA. A normal electronic multimeter has 20kOhms or more input impedance, so would only give you 12mA or so. Also, you don't know whether any other equipment on the supply is also leaking curent.

 

[M77]

What range were you using it on - Auto LZ or AC voltage? Apparently, the auto range is a low impedance input (doesn't say how low), so that might trip the RCD on its own - it only needs 30mA. A normal electronic multimeter has 20kOhms or more input impedance, so would only give you 12mA or so. Also, you don't know whether any other equipment on the supply is also leaking curent.

Yeah I was using it on Auto lz. It's a new meter so still not sure about all its functions. Maybe that's it, there must be very low resistance on auto lz, this has never happened with my old meter.

 

[Crinkmeister]

I can't find the value for the Auto LZ range, and the normal range is probably a lot higher than 20k on a modern meter - more like a Meg. Try on the normal AC Volts range.

 

[stani]

Was your old meter an analogue type ( needle) not digital. What were you testing for, just out of interest.

 

[Crinkmeister]

Found it - in the manual. 3k on auto, so 80mA. Enought to trip RCD.

 

[M77]

Thanks crink, must have been that! I'll check it out tomorrow, good to know how to actually use this meter.
Stanni my old meter was digital and I was just tracing wires for new controls.

 

[Billy Bob Bob]

Thanks crink, must have been that! I'll check it out tomorrow, good to know how to actually use this meter.
Stanni my old meter was digital and I was just tracing wires for new controls.

not set it on continuity by mistake? that would explain it

 

[zzzjim]

Found it - in the manual. 3k on auto, so 80mA. Enought to trip RCD.

Sounds a bit of a low resistance to have across 230V !
18 Watts wasted a meter (if its resistive)

 

[M77]

Definatly not on ohms! Just tested it at home, tripped rcd on auto-loz but not on acv.

 

[Crinkmeister]

I agree zzzjim.It's quoted in the manual on page 22 if you want to check it out

 

[Crinkmeister]

Yes - don't use it on Ohms on mains! I did that once by accident when I was a nipper - analogue meter - it went pop!

 

[zzzjim]

Had a peek at sheet .Don't use AUTO-V on higher voltages as it says LoZ

(Means low impedance--No Nuisance readings from small stray signals)

Use V~ for high AC / Mains voltages

 

[stevetheplumber]

i once pierced a cylinder by testing live to earth(cylinder) with the guage set on ohms or amps burnt straight thru had to drain and solder it up that combination of water and electrics definitely freshen the brain cells