Consumer unit, is the following acceptable practice ?

[julioarca]

Got a customer who's house is subject to nussiance tripping, cannot find any real problems with insulation tester.

Trips mainly on mornings, never at night, with no appliances on either.

Suggestion, change DB to split load, main switch for lighting and feed to two 30mA rcd units in the board. One unit feeding up sockets and shower, the other unit feeding down sockets and cooker.

This way if fault appears it will trip out the relative rcd unit thus reducing the circuits to check, as I say insulation test showing no probs on inspection etc.

Any good?

 

[streetlighter]

What about using RCBOs for each circuit ? expensive but a lot better than a split load arrangement.

 

[Qedelec]

Is the main switch a 30mA RCD? What level does the ramp test trip it?

 

[julioarca]

Is the main switch a 30mA RCD? What level does the ramp test trip it?

the main rcd is 30mA, rcd tested to 30mA then trips

 

[julioarca]

What about using RCBOs for each circuit ? expensive but a lot better than a split load arrangement.

I had thght about this, but would the above config in a DB be acceptable, correctly labled etc.

 

[Adam_151]

I had thght about this, but would the above config in a DB be acceptable, correctly labled etc.

if its made up on site, using your own wire links, then perhaps not... however boards like this are available made up in order to allow installers to try and meet BS7671:2008, perhaps refered to as a '17th edition board'

 

[DESL]

the main rcd is 30mA, rcd tested to 30mA then trips

was that on the ramp test?

You really need to determine the cause of the tripping especially if ramp test is showing 30mA trip current.

I don't think changing the DB will eliminate 'nuisance tripping' if present RCD is within spec. All it will do is limit the 'nuisance' to fewer ccts.

Are you sure all appliances are off?

Is there a problem with boiler/CH/hot water ?

Faulty shower - as you said only trips in morning.

A little more detective work required - ask the customer what they do in mornings - switch on loads of PCs

 

[davedasave]

did you not look in their bedroom at the alarm clock?