New RCD tripping

[phil d]

But...  You meter is only outputting a very small fault current to test the RCD itself..  

Which may not be sufficient to operate the RCD when tested out on a circuit due to other circuit losses through fixed equipment that may not have their neutrals isolated..

In your scenario where trips ok with meter at RCD..  But doesn't trip at a socket out with meter..

( which i have seen myself numerous times )..

Have you actually gone on to test it with a more realistic fault..

e.g. back in earlier GN3 days, before RCD's became more common place,

a note used to suggest using a 15watt pygmy lamp wired between live & earth to verify an RCD tripped..

(I still have plug & lamp & pretty much always trips the RCD at a socket even if my meter doesn't) 

15Watt lamp is a tad higher than the basic 30ma fault.  (nearer a 65ma fault)

AND very very very rarely would a real fault be only 30ma.

and/or have you tried a Zs through the RCD to see if it trips?

You can end up chasing yourself up your own rear-end trying to get your meter to give a valid RCD test at all points on a circuit..  

Which is probably why the regs DONT ask you test in circuit! 

:coffee

Yes, I have one of those new led martindales, that adds the load when you press the buttons,one way or another I always like to see an RCD trip at an actual point of use, I've always thought what the reaction of a coroner would be if someone did get a scenario where when tested at the DB a device tripped but didn't trip at a socket, or they didn't even bother proving it tripped at point of use, I'm sure it would be a very interesting conversation.

Incidentally do you remember back in the good old days, before everyone had a loop tester, proving earth on a metal sink top with a Drummond test lamp? I remember an old spark showing it me when I was an apprentice, "if the lamp lights it's earthed" he told me, which even today while it might be frowned upon it would still suffice in an emergency if you hadn't got a meter available.

I love collecting old test gear, I have an old green 'megger' ohmeter, brand new in the box, inside the box alongside the instruction leaflet there is a note from Megger that congratulates the owner on purchasing a quality instrument and states that if they send this note along with their name and address, they will send by return a copy of the wiring regulations FOC, I wonder if they'd still honour that? lol

I have quite a few old Avo meters as well as a few old Edgcumbe Peebles ones and numerous old test lamps, my old Martindale MTL7, a Square D 'wiggy' brand new in the box, a couple of other solenoid testers and a very early wooden one! It really is a thing of beauty, a wooden box containing two 15W pygmy lamps in series, out of this comes 2 single core flexes, single insulated, and on the ends of this are two wooden handled probes, with built in fuses. Imagine using something like that today, H&S would have a dicky fit!

The thing that always amazes me is how much people think the old Avo meters are worth, granted the last models made are still useable and are still fetching up to £250, I have and use one myself on occasion, but the really old ones are purely for show now, you can pick them up for an average of about £40, yet recently there were a couple on fleabay for over £500!.

 

[kerching]

I have a relatively rare AVO Panclimatic Model8 which also,measures capacitance