Fault driving me mad!!

[Rockingit]

Can't you install a second RCCD and split the loads with standing leakage between the two. This should bring it back to within the 30mA threshold.

It's a split board already, and shoe-horned into a tight space so fitting another CU won't work.

@Spin - reason for still wanting to have them on RCD is simply that the heaters themselves are vulnerable to things like drinks spills, toddlers pulling on the inlet cables etc. So yes, whilst I could probably justify having them only on MCB's, I'd rather have them with some leakage protection, even if it's higher than usual. And yes, I did of course mean departure!

All of this, and reading Ackbar's thoughts, begs the question of what do we do as installers and designers to slow this process down in the future. Are we really going to start installing high integrity circuits in domestic houses, splitting circuits down to 1-1 configurations on RCBO's etc? So much technology in peoples houses now, no chance of that slowing down, so what do we to future proof? I've just done a tender / design on a massive 'grand designs' kind of build, and it's almost pretty much one rccb, one cable, one outlet. Big expense.

 

[Marvo]

I never thought of RCBO's, we don't see them much where I am. I would say these are the way of the future, a single RCCD is putting all your eggs in one basket when it comes to an earth leakage fault (or overall accumulation in your case). It's the equivalent of running multiple socket circuits on a 60A MCB and expecting it to effectively protect them. If RCBO's are economically viable and they fit into a single space in the CU then they have to be the best option.

 

[spark 68]

Hi,

Split board with two RCD's that ramp test to around 21-22mA each

to minimise the nuisance tripping is to put the two heater circuits (being the most individually leaky) onto individual 100mA RCBO's and declare them as dedicated circuits

It's a split board already, and shoe-horned into a tight space so fitting another CU won't work.

I may be missing something here, but if it is a split load board already, protected by two 30mA RCD's, one for each side, then how is it possible to fit 100mA RCBO's ?, as this will not solve your problem, as the 30mA RCD's will still trip before the 100mA RCBO's, as there is no discrimination whatsoever here, the only way would be to put a mini CU fed with tails from the incoming side, as others have already suggested.

What Iam saying here, is you will have 30mA RCD's feeding 100mA RCBO's.

 

[Silly Sausage]

68, I assume he's going to fit the 100mA RCBOs into the high integrity section of his CU, ie the bit fed straight off the main isolator

 

[Rockingit]

I may be missing something here, but if it is a split load board already, protected by two 30mA RCD's, one for each side, then how is it possible to fit 100mA RCBO's ?, as this will not solve your problem, as the 30mA RCD's will still trip before the 100mA RCBO's, as there is no discrimination whatsoever here, the only way would be to put a mini CU fed with tails from the incoming side, as others have already suggested.

What Iam saying here, is you will have 30mA RCD's feeding 100mA RCBO's.

You are!! The board gets reconfigured as a three-way, so 2 x 30mA RCD's feeding whatever, and then two separate RCBO's on the same DIN rail but fed directly. Simples.

 

[Rockingit]

68, I assume he's going to fit the 100mA RCBOs into the high integrity section of his CU, ie the bit fed straight off the main isolator

 

[malcolmsanford]

Then surely if your just going to have 2 X heaters on an RCBO on an high integrity side 30mA RCBO's will be enough? surely the 2 heater alone can not produce 20+ mA Protective conductor current and i'm sure you said in a previous post that they only produced about 5mA a piece, this way you would not have to worry about not having additional protection problems

 

[Silly Sausage]

M, I think R's fed up with problem.
100mA should stop any nuisance tripping, they're knackered 2nd hand ones.
:smiley2::smiley2::smiley2:

 

[spark 68]

68, I assume he's going to fit the 100mA RCBOs into the high integrity section of his CU, ie the bit fed straight off the main isolator ​

You are!! The board gets reconfigured as a three-way, so 2 x 30mA RCD's feeding whatever, and then two separate RCBO's on the same DIN rail but fed directly. Simples

Ahh!,
I had a look through the previous posts, and did not see anywhere it mentioned three way boards, and thought at first you were going to add a mini CU, but if you are going the Three way with RCBO route, then I would do as others have said, and put the heaters on their own 30mA RCBO's, or two per RCBO, then it will still comply with buried cables etc..etc., and the leakage will still be within bounds.

I think you may be correct though, the way things are going RE: amount of home IT and electronic gadgetry in houses now, we maybe going the RCBO route more often than in the past.


Thanks for clearing that up.


All the best Spark 68

Cross posted with Malcom

 

[Deleted member 26818]

Rockingit, if there is no requirement for 30MA RCD protection on these circuits, then providing 100mA RCD protection will not be a departure.
However if there is a requirement for 30mA RCD protection, perhaps due to cables being concealed in walls, providing 100mA RCD protection would be a departure, onlly not an acceptable one, because it would not offer the same degree of safety as would be achieved with providing 30mA RCD protection.

 

[wattsup]

not read the whole, but i would think a thermo couple/thermostat prob