@Leesparkykent means disconnect the circuit and not just switch it off, switching off will not isolate the neutral.
Discuss Rcbo test buttons not working - but works ok when tested in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net
To do what? I've asked in the past about these, and yourself included couldn't give me a reason (let alone a good one) to purchase one.
Why do I need one? I do approx 150-200 call outs for faults a year as a sole trader and yet to not find to fault/issue. All without the use of one. I asked in a different thread why I'd need one, and iirc no one came up with a reason as to why I'd need one.I have identified rcd trips using my clump meter on more than one occasion .... and I often use it before I change a cu ....
They aren’t that expensive ..... why not buy one ?
Andy, would that be because some of the created test current flows back through the neutral side of the sense transformer and then down the CPC resulting in less than the expected test current appearing on the sense winding?
I'm intrigued how a fault purely between any upstream conductors could affect the operation of an RCD, assuming the L-N potential is still 230V. What are your thoughts on the mechanism?My bets is a neutral-earth fault, possibly on one of the two TPN circuits
Read Richard burns post 10 from this link RCD test button not working - https://www.electriciansforums.co.uk/threads/rcd-test-button-not-working.92618/I'm intrigued how a fault purely between any upstream conductors could affect the operation of an RCD, assuming the L-N potential is still 230V. What are your thoughts on the mechanism?
Thanks for the link:Read Richard burns post 10 from this link RCD test button not working - https://www.electriciansforums.co.uk/threads/rcd-test-button-not-working.92618/
As you can see he is talking about the outgoing neutral itself, in a case where the polarity is reversed. post 12 explains the same thing now clearlyIf there is a neutral earth fault in a circuit then when the RCD test button is pressed the current that should flow from the test button, to out going neutral,
This is confirmed by the original postIf the test button circuit goes from supply L to load N, a downstream N-E fault can stop it working by reducing the test current returning to the supply N through the sensing transformer. But if the test was from load L to supply N, the fraction of test current going to earth at the fault would pass through the transformer twice in the same direction, possibly making it test OK even if it had reduced sensitivity. This makes me think that all RCDs have the test circuit the first way round, but I can't say I've spent enough time looking at the schematic on the side to notice.
with 2 30mA rcd, left side wont trip when test button is pushed but the right side seems fine
Has the customer been periodically testing them? I find a lot of the time they stick as never tested.I'll have to go back with my leakage clamp meter and check it out .. customer would be a tad unhappy to buy 6 new ones ....that also didn't work.
Sorry, just seen this thread.Hi all
Odd one today .. all 6 Hager rcbo's in a tn+n db have the test buttons not working..
But when tested with a multifunctiontester they react fine..
Now..I guess I'm going to have to fail them..even though they work fine.
Hager technical say they have never heard of this.
Db is in a plant room with a raised ambient temperature but not hugely ..say 36c .. rcbos are 2 x 6A B 30ma 2 x 20A C 30ma and 2 x 32A B 30ma .. fitted in 2014 by the looks of it.
All connections are good..fly leads good..circuit's are just for sockets and lighting..standard stuff.
Anyone had this before..
Any ideas
Ta
Vito
Reply to Rcbo test buttons not working - but works ok when tested in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net
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