Discuss Nuisance tripping - faulty RCD? in the UK Electrical Forum area at ElectriciansForums.net

Have a look at this old thread. It's usually old Memera RCDs that seem to be a problem with smart meters. I haven't heard of it happening with Proteus, but that's not to say it doesn't happen.

Ah, thanks for that. It's not something I've come across before but it would make sense if that was the cause.

Not sure how I'm going to charge for this job, having wasted so much time going down dead ends!
 
Ah, thanks for that. It's not something I've come across before but it would make sense if that was the cause.

Not sure how I'm going to charge for this job, having wasted so much time going down dead ends!
That’s the nature of fault finding.
You have to charge the time it takes to find the fault…. Not just the end repair.
 
I always make it clear before starting a fault finding job that it's charged at an hourly rate, as it's impossible to say what the the fault is until, well, you've actually spent time looking for it!
I usually give an estimation of how long I think it's likely to take though...
 
That’s the nature of fault finding.
You have to charge the time it takes to find the fault…. Not just the end repair.
I get that, just thinking that I could have saved myself a lot of time if I'd tried putting the downstairs lights onto the upstairs lights RCBO before lifting the floor and inspecting the circuit.
 
Even with all conductors on the affected circuits disconnected?
I understood from your post that you disconnected the shower, the immersion but not the lights?
If you did of course disconnect all the affected conductors (lives and neutrals) then by default you would have isolated any N to E fault and the rcd should not trip.
Whenever I have experienced an rcd tripping with no load connected it was always because of an N to E fault in the installation combined with a DNO neutral that had a significant volt drop, (10 to 12 volts) causing a circuit to flow between N and E in the installation.
 
If tripping with no load then it has to be the RCD/RCBO's fault one way or another. Either it is actually faulted inside, or it lacks EMC protection against smart meters.

The whole EU (and thus UK) EMC directive came in to force around 1996 and was unusual compared to older rules on causing RF interference in that it also required certain minimum standards of RF immunity as well. But as always there was some "wriggle room" in how you interpret the rules and many companies paid only lip service to it. In particular you could define what constituted "failure" in a way that would allow you to get out of certain things - so you could say that a Walkman style unit need not work with a mobile phone adjacent to it as you would not be using both at the same time, and so close mobile phone operation causing transient degradation was allowed as a pass.

I have no idea if the makes of the RCBOs assumed nobody would have a phone 0.3m away all the time and so did not take sufficient steps to filter it, after all those extra capacitors costing £0.01 would seriously impact on the profits...

As well as newer RCD/RCBO hopefully being more immune by design due to the knowledge that RF transmitters adjacent to the CU are the "new normal", the move to metal CU also should help there. Though the cables going in/out mean the reduction in RF is not nearly as large as you might hope for, but it will still be better than plastic CU!
 
This is a totally unknown area for me.Smart meters have only started to be really rolled out here in the last 2 years.Have never yet been called out to a tripping rcd fault that transpired to be caused by a smart meter.A question that crops up in my mind is this.Would the older more "traditional " rcd,s /rcbo,s ( so less electronics) be less suseptable to this issue?
 
This is a totally unknown area for me.Smart meters have only started to be really rolled out here in the last 2 years.Have never yet been called out to a tripping rcd fault that transpired to be caused by a smart meter.A question that crops up in my mind is this.
I don't do most of this "professionally" so can't comment on the percentage of faults due to this reason or other reasons.

Would the older more "traditional " rcd,s /rcbo,s ( so less electronics) be less suseptable to this issue?
The very original sort with just a sensitive trip coil and differential transformer would not be bothered by RF. But if you start having electronics in there the issue of RF causing upsets has to be addressed as basically and diode junction (part of transistor, etc) will rectify the very high frequency RF and generate a DC or low frequency term from it.

Many products from older times suffered badly from EMC issues as mobile phones came in as they were never tested for it, and in the past you would not have had a 0.1W or so transmitter only 30cm away (at least outside of a radio amateur's home, which is equivalent to a 11kW transmitter at 100m, or 10MW at 3km away). By to 2000s that was common and so companies had to start fixing stuff, but how quickly products were checked/modified is anybody's guess!
 

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