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With have heard reports of smart meters tripping RCDs, is there any more than anecdotal evidence?
How many surge protected extension leads can you supply from one 30 mA RCD?
The customers have five supplied from one ring circuit and RCD that has been tripping. They have said the RCD still tripped with all of them disconnected.
He customers also think the central heating boiler and controls are causing the RCD tripping, they are on a completely different circuit and 30 mA RCBO that doesn’t trip.
Could a switching spike on the boiler circuit make the socket circuit with all the SPD protected extension leads RCBO trip without tripping the boiler circuit RCBO trip?
I find it hard to believe the boiler would trip the sockets unless there is some really weird cross connection that I am sure you have already eliminated.
In terms of how many of those leads on one RCBO, as many as you fancy pretty much - so long as they are in good condition - and less than one where the MOVs are starting to fail after a few oversize surge events.
The data sheet says 2 x MOV + GDT which tells us the sort of surge suppression - two of the semiconductor type and a gas discharge tube (like an enclosed spark gap in a special atmosphere.) I'd expect a star config of Mov L-centre, N-Centre and the GDT from E to centre. There may even be a fusible resistor in series with the live to prevent a fire when the MOV is end of life..
370 joules sounds like a lot for a single MOV disk, so there may be a few in parallel, or one large one of about inch diameter in each position (example)
When new the capacitance is a few hundred pF, so the cable will be more than that - we can discount capacitive leakage through the MOV being an issue - but only if it is in good order. The MOVs should not leak on a 250V test between L-E or L-N . (or indeed on anything up to the crest of 253V RMS, about 330V DC, but that is not an easy test voltage to generate.)
Mike.
I find it hard to believe the boiler would trip the sockets unless there is some really weird cross connection that I am sure you have already eliminated.
In terms of how many of those leads on one RCBO, as many as you fancy pretty much - so long as they are in good condition - and less than one where the MOVs are starting to fail after a few oversize surge events.
The data sheet says 2 x MOV + GDT which tells us the sort of surge suppression - two of the semiconductor type and a gas discharge tube (like an enclosed spark gap in a special atmosphere.) I'd expect a star config of Mov L-centre, N-Centre and the GDT from E to centre. There may even be a fusible resistor in series with the live to prevent a fire when the MOV is end of life..
370 joules sounds like a lot for a single MOV disk, so there may be a few in parallel, or one large one of about inch diameter in each position (example)
When new the capacitance is a few hundred pF, so the cable will be more than that - we can discount capacitive leakage through the MOV being an issue - but only if it is in good order. The MOVs should not leak on a 250V test between L-E or L-N . (or indeed on anything up to the crest of 253V RMS, about 330V DC, but that is not an easy test voltage to generate.)
Mike.
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