New boiler tripping RCD

[JohnD]

IME electrical trips from pumps or thermostats or motorised valves happens when there is a water leak getting into the connections. They are well-protected against internal problems.

Plumbing parts that carry electricity are easily affected by water leaks. Look for any traces of limescale or green stain and clean it off. If it comes back you know the leak is live.

Sometimes the leak is in the boiler and drips onto the PCB or other electrical part.

 

[ericmark]

The Eaton range

has a RCM built in so warms when near point of tripping, but not seen any others with that feature. And with all the test equipment I still failed to find out why every so often my RCD would trip in the last house.

I blamed spikes on the supply, but without an oscilloscope unlikely to find it, and even with one, once tripped too late to read display.

 

[ericmark]

The Eaton range View attachment 264901 has a RCM built in so warms when near point of tripping, but not seen any others with that feature. And with all the test equipment I still failed to find out why every so often my RCD would trip in the last house.

I blamed spikes on the supply, but without an oscilloscope unlikely to find it, and even with one, once tripped too late to read display.

I think if me I would replace the RCD with an isolator and fit all RCBO's.

 

[TheGovernor]

The Eaton range View attachment 264901 has a RCM built in so warms when near point of tripping, but not seen any others with that feature. And with all the test equipment I still failed to find out why every so often my RCD would trip in the last house.

I blamed spikes on the supply, but without an oscilloscope unlikely to find it, and even with one, once tripped too late to read display.

I think if me I would replace the RCD with an isolator and fit all RCBO's.

So my thinking is get the pump done (which is happening on Thursday) double fingers crossed that alleviates the current issue and then I can get a new board with RCBO's to future proof things in case of future problems. When I do that I'll probably get the heating circuit separated from the kitchen sockets.

I'll check out that Eaton...

 

[stem]

I would wire the pump directly to a 13A plug (with a 3A fuse in) turn the heating / boiler off and just leave the pump plugged in and running. With a 3 port valve there will always be a 'route' open for water flow. Then if the RCD doesn't trip it's not the pump at fault. If it does it's not the boiler because that's off.

 

[TheGovernor]

I would wire the pump directly to a 13A plug (with a 3A fuse in) turn the heating / boiler off and just leave the pump plugged in and running. With a 3 port valve there will always be a 'route' open for water flow. Then if the RCD doesn't trip it's not the pump at fault. If it does it's not the boiler because that's off.

That's an interesting thought... I have an inkling this happens when the heating is hot due to when it has tripped in the past, so I guess that test wouldn't account for that?

The other problem is how long it can take to trip, it can easily run fine for 10, 12, 15 hours then randomly trip, doesn't seem to matter how much load there is either...

 

[ericmark]

I do like @stem idea of putting pump on plug and socket.

The other problem is how long it can take to trip, it can easily run fine for 10, 12, 15 hours then randomly trip, doesn't seem to matter how much load there is either...

This is the problem I had with old house, never could put my finger on why it tripped. All sorts of ideas, but no real way to prove it.

In around 1992 I returned from working in the Falklands, until then the ELCB as it was then called, was a rare beast only used with TT (earth rod) installations, the IEE wiring regulations had just been made into a British Standard BS 7671:1992 and there seemed to be a shift onto safer systems, and Sizewell 'B' seemed to be full of the ELCB, RCCD, or RCD which ever name you like, and they were a huge problem, in the main due to not switching neutrals, so some thing switched off, was not isolated, so a neutral to earth fault could still trip the RCD even when switched off.

The other was lack of discrimination, we would have a 5 amp and 5 seconds RCD feeding a 1 amp at 1 second, feeding a 100 mA type S feeding a 30 mA at 40 mS and some one would cause an earth fault and every RCD would trip, some times it would only take the 30 mA one out, but also would have them all trip together.

I had a workshop with a 10 mA MK metal clad socket, and pressing the test button would also trip the 100 mA one in the main board.

However over the years they do seem to have improved, and they don't trip as easy, however still loads of the old ones around, today the 30 mA RCD is sold as four main types, the type AC

should have the single sine wave sign, my old ones don't have any sign, it seems type AC can be frozen by DC so today we tend to use type A

these can stand 6 mA of DC, and there are other devices to detect the DC so if there is DC the other device will trip, then we have the high frequency

where we are using switch mode power supplies we can get high frequency, personally never fitted one, and not seen a RCBO as type F or for that matter type B which is next in the list type B

are used with EV charging points and solar panels and will work with over 6 mA DC out of interest which type do you have?

 

[ericmark]

Note Bosch it seems wants type A RCD's.

 

[TheGovernor]

out of interest which type do you have?

So this my very old CU, I have type AC on my RCD. I've got my (usually tame) electrician coming round on Friday to price me up an RCBO CU, and we've talked about splitting some of that large Kitchen/Lounge/Bedroom 1 & 2 plus utility room circuit up. I'll definitely be putting the heating on it's own RCBO and with a bit of luck maybe split the Utility room or lounge off too, just to make it a more sensibly sized circuit.

As you say above, it is a nightmare though, the intermittent, load independent and irregular timing of these trips is a real hassle. I've been looking for some reasonably priced audible alarms that will sound if the power goes, that way I could at least leave the heating on when we go to bed knowing I'll get alerted if it goes but haven't found one yet... right now the only consistent thing is if I switch heating/hot water off when we go to bed, I don't get any tripping.

Thanks for all of the insight on this thread, I really do appreciate it

 

[ericmark]

I use the Lidi rechargeable touch, it auto lights with a power cut, so it draws on attention to loss of power, also have one I think came from Tesco, There is a movement sensor which will make it light in the dark with movement, used in the caravan I put tape over it, here at home it lights the stairs at night.

Sorry to say GE did not last long in the UK, and a consumer unit is a type tested distribution unit, so fitting another make of MCB or RCBO would mean it is no longer a consumer unit as not type tested, and when the installation is in the control of an ordinary person which your house is, then we should use type tested appliances, so an electrician is likely to be unwilling to fit some other make of RCBO in that box. Even if there is one that fits.

 

[ericmark]

A 10 way fusebox consumer unit Height 259mm Width 306mm will it fit in the space?

 

[CBW]

Which circuit is the heating on? I’m guessing sockets?

 

[TheGovernor]

A 10 way fusebox consumer unit Height 259mm Width 306mm will it fit in the space?

At a push, we'd need to either cut into the top of the cupboard to make space for it, or re-site it elsewhere, the electrician is coming round to have a look on Friday, but also yes, my intention was that the unit would go and we'd get a new one with RCBO's, rather than fit RCBO's to the old board.

Which circuit is the heating on? I’m guessing sockets?

Yep, the heating is on the kitchen sockets, along with the lounge, utility, Master bedroom, 2nd bedroom... it's a crazy big circuit! Like I said above I think, I'm planning to get that circuit split up a bit to reduce load on it, but also to narrow down any future tripping issues...

 

[TheGovernor]

I use the Lidi rechargeable touch, it auto lights with a power cut, so it draws on attention to loss of power, also have one I think came from Tesco, There is a movement sensor which will make it light in the dark with movement, used in the caravan I put tape over it, here at home it lights the stairs at night.

Sorry to say GE did not last long in the UK, and a consumer unit is a type tested distribution unit, so fitting another make of MCB or RCBO would mean it is no longer a consumer unit as not type tested, and when the installation is in the control of an ordinary person which your house is, then we should use type tested appliances, so an electrician is likely to be unwilling to fit some other make of RCBO in that box. Even if there is one that fits.

I've actually bought one of these to make sure I wake up, it's a non maintained LED so come on with power loss

I'll keep looking for something audible as an ideal, I found one thing but apparently it's deafening, so not sure that's the way to go...

 

[TheGovernor]

I left the heating on last night... no trip oddly...

New pump and Programmer gone in to day in any case, so wait and see time for me...