Eart Fault Menvier Mv400 Panel

[Guest Cerberus NI]

The one with the smoked plastic door and the isolate relay switch?

Yuk!

I have know panels "ignore" earth faults while a zone fault/sounder fault is active. That's why I advisded clearing the panels faults before anything else, it may well work the way you describe so it's worth trying?

I think that it's this 'un! http://www.cooper-ls.com/downloads/mf200_400_fire_manual.pdf

[JohnCunningham]

I think that it's this 'un! http://www.cooper-ls.com/downloads/mf200_400_fire_manual.pdf

Eye its that one. Not been back there today but will soon and report back my findings

Thanks all

[luggsey]

I think that it's this 'un! http://www.cooper-ls.com/downloads/mf200_400_fire_manual.pdf

Oh that's newer then the one I was thinking of!

[camerabloke]

Yes I have known faults "appear" after years of trouble free operation, it happens! You need to find out if it's in the panel don't forget, that's why disconnecting all external wiring first and clearing the panels faults is the best way to go.

You can use your multimeter on the external wiring, that works as well?

Paul.

didnt you say this in a previous post?

Disconnecting zones will simply cause more faults which will stop you locating the fault you are looking for.

[luggsey]

didnt you say this in a previous post?

Disconnecting zones will simply cause more faults which will stop you locating the fault you are looking for.

Clearing the faults means installing all the EOL's as I explained in the previous post.....

[Guest Cerberus NI]

didnt you say this in a previous post?

Disconnecting zones will simply cause more faults which will stop you locating the fault you are looking for.

...but it should clear the earth fault! (groundhog day or what???)

[arfur mo]

hi guys,

not wanting to intrude, but just curious.

are megga's not used for routine earth finding? obviously not across the line (and blowing up the kit ) but remove from panel short both zone legs together and test down to earth.

on intruder in (my ) time honoured tradition, i'd place a standard volt meter from good earth point to each side of the standby battery in turn, any readings would indicate the polarity and also the severity of any suspected fault, simple and quick test i do on every pm maintenance.

if a fault shows, with the meter left attached simply diss off each zone or bell circuit until the fault drops off. if on a zone a 'divide zone by 50%' and test approach would be used.

or has it all changed?

regs

alan

[luggsey]

hi guys,

not wanting to intrude, but just curious.

are megga's not used for routine earth finding? obviously not across the line (and blowing up the kit ) but remove from panel short both zone legs together and test down to earth.

on intruder in (my ) time honoured tradition, i'd place a standard volt meter from good earth point to each side of the standby battery in turn, any readings would indicate the polarity and also the severity of any suspected fault, simple and quick test i do on every pm maintenance.

if a fault shows, with the meter left attached simply diss off each zone or bell circuit until the fault drops off. if on a zone a 'divide zone by 50%' and test approach would be used.

or has it all changed?

regs

alan

It's rare on an analogue system to need anything but the panel to trace faults in the cabling (Specially if it's Gent.. )

To narrow down a fault a multimeter is normally all that I use, however there are rare occasions when a high z fault will not show on a multimeter and then it's a case of getting the megger out and in your case Alan winding it up!

On analogue systems I always remove devices before insulation testing a single length of cable, I can normally track down the offending bit of cable using the panel and then confirm it with the megger. On a conventional systems the multimeter may/not work depending on the fault but most of the time the good old DVM does the job for me.

Anybody else had fun tracking down faults in MI 3 wire systems? Thank goodness most of them have gone now, I almost zapped myself on one once before I realised it was 240v!

[arfur mo]

It's rare on an analogue system to need anything but the panel to trace faults in the cabling (Specially if it's Gent.. )

To narrow down a fault a multimeter is normally all that I use, however there are rare occasions when a high z fault will not show on a multimeter and then it's a case of getting the megger out and in your case Alan winding it up!

On analogue systems I always remove devices before insulation testing a single length of cable, I can normally track down the offending bit of cable using the panel and then confirm it with the megger. On a conventional systems the multimeter may/not work depending on the fault but most of the time the good old DVM does the job for me.

Anybody else had fun tracking down faults in MI 3 wire systems? Thank goodness most of them have gone now, I almost zapped myself on one once before I realised it was 240v!

hi luggsey,

with the passing of 'laced wiring' and tube batten frames i've not used a megger for 20 odd years, but i still have 2 x TMK battery units just can't throw them out.

developing only 500 vac. but a lot of fun with a supervisor 'tasting' the voltage on his tounge at the far end for intermittents (real old school stuff) when you happened to hit the test button - eye watering just don't describe, lucky i was a fairly fast runner them days .

regs

alan

[JohnCunningham]

meggers ( or insulation resistance testers) are great but I don't like using them even tho I use them all the time. The thought of 500v along a line with a 24v something still connected by accident is costly. So I stick to a multimeter till I am absolutely sure.

When electrical installation testing on 240v I always megger at 240v first, the readings tell me whether something is still connected, if all clear then I test at 500V. Bolloxed a fridge freezer once with a 500V megger. The cost and explaining it to the customer was not a great experience.