RCBO tripping.

[Burnerman]

Schneider 10 mA RCBO £113.18 you can clearly get them, but does seem unlikely.

However if you say it is a 10 mA I have to believe what you say.

I wouldn't believe a word I say, eric , it's just what the electrician told me. I'll investigate tomorrow....I guess all the info I need will be printed on the RCBO.
John

 

[Burnerman]

As it's an RCBO, the problem may not be earth leakage - it could be tripping on overload or due to the starting current of the motor being too high. Particularly if it's a low rating, or there are other factors such as that RCBO being situated next to others which run at high loads for long periods, or it's in a location with high ambient temperatures.

Need to establish exactly what the RCBO ratings are, and where it's located relative to others, and in what environment.

There is also the possibility of the circuit wiring being damaged somewhere or other problems with the connections.

Originally the boiler was on it's own dedicated circuit, controlled by a 5A MCB. The entire building was protected by one 100mA earth leakage breaker and it never tripped at all.
Thanks for your input!
John

 

[Burnerman]

https://www.flameport.com/electric_museum/old_elcb/chilton_elcb.cs4
Although by no means identical, this is the sort of thing my house had.....connected between the meter and consumer unit, not within it.
John

 

[jj4091]

I presume the circuit supplying the boiler has been rewired during the electrical work but I think you should rule that out first. Are you capable of fitting a plug to the boiler lead & connecting it to an extension lead plugged into a separate circuit, if necessary, for a little while.

 

[Burnerman]

The boiler circuit is original, jj - as it's original time clock broke down years ago I have it plugged into a 24hr domestic timer rated at 13A.
Once the boiler tripped for the first time, I rigged it up via an extension lead to the utility room ring main.....and it popped that too
That is fed via a 32A RCBO, presumably with the same mA rating.
So, the issue is definitely with the boiler somewhere.
Just for info, its a Thorn Panda 55 oil boiler....oldie but goody!
Thanks for your interest!
John

 

[Chunky19]

"Once the boiler tripped for the first time, I rigged it up via an extension lead to the utility room ring main.....and it popped that too"
Now I'm confused. This 10mA RCBO I presume is in a new consumer unit feeding the boiler only circuit? So are you saying when plugged into a extension lead in the utility ring circuit it too tripped. I doubt very much that is a 10mA trip. 30mA would be the norm, sounds like a worse intermittent fault.

 

[Burnerman]

Yes, I now have a spankers consumer unit, all with RCBO’s.
I’m not at the house now but will check things out tomorrow.....I’m sure the electrician said they were all 10mA items but I may well be wrong.
Hopefully the rating will be printed on the RCBO so I’ll report back then.
Thanks for your interest!
John

 

[JohnW2]

The homework I'll do is to investigate eric's TT and TN systems......completely unknown to me but I understand them now!

Fair enough. That's certainly good for your education but, as I implied, I don't think it's particularly relevant to your current issue/problem.

Kind Regards, John

 

[Burnerman]

Thanks John.
Connecting a capacitor across the mains input.....as an anti spike device or am I barking up the wrong tree?
John

 

[Harry Bloomfield]

The boiler circuit is original, jj - as it's original time clock broke down years ago I have it plugged into a 24hr domestic timer rated at 13A.
Once the boiler tripped for the first time, I rigged it up via an extension lead to the utility room ring main.....and it popped that too
That is fed via a 32A RCBO, presumably with the same mA rating.
So, the issue is definitely with the boiler somewhere.
Just for info, its a Thorn Panda 55 oil boiler....oldie but goody!
Thanks for your interest!
John

Then I would be pulling out a Meggar and checking for earth leakage.

 

[EFLImpudence]

Other makes are available.

 

[JohnW2]

Thanks John. Connecting a capacitor across the mains input.....as an anti spike device or am I barking up the wrong tree?

If such is what you are suggesting, 'spikes', per se, should not cause an RCD or RCBO to trip (although some people think this may sometimes happen). If one were concerned about this, 'Surge Protection Devices' are becoming fashionable (and 'almost required by regs').

Kind Regards, John

 

[Harry Bloomfield]

If such is what you are suggesting, 'spikes', per se, should not cause an RCD or RCBO to trip (although some people think this may sometimes happen). If one were concerned about this, 'Surge Protection Devices' are becoming fashionable (and 'almost required by regs').

I think spikes can do that, though I have little idea of how it might happen, just practical experience. I would not expect any 'Surge Protection Devices' to be fitted at all.

If Burnerman cannot find another cause for the trip, I would be looking at any suppression caps in the circuit - those I would expect to find, to suppress interference.

 

[JohnW2]

I think spikes can do that, though I have little idea of how it might happen, just practical experience. ...

Even though "it shouldn't happen", I don't think it would be particularly surprising if it sometimes does. Virtually all residusl current devices these days have electronics which 'trip' the disconnector and, just like anything else electronic, they can be susceptible to the effects of 'spikes' etc.

I would not expect any 'Surge Protection Devices' to be fitted at all.

Nor would I.

If Burnerman cannot find another cause for the trip, I would be looking at any suppression caps in the circuit - those I would expect to find, to suppress interference.

Indeed. Filter/suppression capacitors between live conductors and earth (but not capacitors between L & N, which I think is what the OP was referring to) certainly have the potential to trip RCDs, particular if they become 'faulty'.

Kind Regards, John

 

[Burnerman]

I'll get cracking with my meter once the boiler comes visible again......building work going on big time! I just need it to work well enough for now.
The burner is an Inter 10, and the only cap is on the motor as a start capacitor but the transformers on these do provide quite a hefty current to ignite the fuel, and I wondered if there was a clue there.
The electrician is also tending to an earth issue (rod in the ground).....he's getting a reading of around 400 ohms but wants that reduced considerably.
John