RCBO nuisance tripping

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Marcus
Posts: 292
Joined: Mon Nov 08, 2021 6:25 pm

Re: RCBO nuisance tripping

#11

Post by Marcus »

resybaby wrote: Sun Jan 26, 2025 4:12 pm Thanks for the reply Marcus.

Its a Sunsynk ecco hydrid with batteries and ac coupled, so yes all current via the rdbo.

The iffy wiring is just a cheap waterproof external socket kit from Screwfix bolted to the rear of the house and fed via fused spur from the house sockets ring main. The shed/pond/tortoise is simply fed from that external socket via some 2.5mm Twin and earth i had lying around installed through my log store, which then supplies a triple socket in the shed, and onto the pond/tortoise via domestic plugs. Its certainly not installed to part p or anything, im kind of assuming the external socket may be letting water in given the issue only occurs after heavy rain, and everything else is under cover.
Ok, well in theory, if only the inverter (and any attached pv) are connected via that rcbo, then the iffy wiring is exonerated,
as the fault causing the tripping must be on thet rcbo circuit, as that rcbo cannot 'see' faults on other circuits.

I guess the next question is if Sunsynk specify a type of rcd? And if double pole is required you may have to change it anyway (can't remember if the fusebox RCBOs are double pole or not).

I assume the max ac input/output of the Sunsynk is within the current rating of the rcbo.
Not thinking of removing the main 100a switch, just adding an Rcd in place of the spd (i understand these 'wear out' in a few years and i dont want to leave the wife with that headache in the future).
I stand to be corrected but i'm not sure an old spd would cause problems - just stop doing it's job.
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resybaby
Posts: 356
Joined: Thu Aug 17, 2023 3:33 pm
Location: Cornwalls North Coast

Re: RCBO nuisance tripping

#12

Post by resybaby »

Marcus wrote: Sun Jan 26, 2025 5:46 pm [quote=resybaby post_id=55379 time=
Ok, well in theory, if only the inverter (and any attached pv) are connected via that rcbo, then the iffy wiring is exonerated,
as the fault causing the tripping must be on thet rcbo circuit, as that rcbo cannot 'see' faults on other circuits.

Well that would be good news and cut down the work needed replacing the outside iffy stuff - and i suppose i could initially change just the Rcbo (but to a type B rather than the current A), afterall it may have gone faultly itself.

I guess the next question is if Sunsynk specify a type of rcd? And if double pole is required you may have to change it anyway (can't remember if the fusebox RCBOs are double pole or not).

Will dig the manual out to see if they specify any particular RCD, i had to change my Sunnyboy one a while back as the installer fitted a 30mA and the manual says 100mA. Will also check the fusebox datasheet.

I assume the max ac input/output of the Sunsynk is within the current rating of the rcbo.

Invertor is 3.6kw, so should be ok with 16a, although installer has fitted a 20a
Not thinking of removing the main 100a switch, just adding an Rcd in place of the spd (i understand these 'wear out' in a few years and i dont want to leave the wife with that headache in the future).
I stand to be corrected but i'm not sure an old spd would cause problems - just stop doing it's job.
[/quote]

Well that is good news, i will leave that alone then. Odd that it fails 'working' rather than fails 'safe' as such, but as long as it doesnt leave the wife with a panic phone call needing a sparks im happy with that.

Thanks all for the help
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