fault finder

[333rocky333]

you could try leaving that mcb off for now and your neighbour may then realise something not working.

What were the other circuits labelled as.
It is quite possible downstairs sockets are on more than one circuit.

Some fuseboards come with made up sticky labels
and it is not unheard of for a downstairs socket label being used for say
an outside socket or a shed socket

 

[bernardgreen]

When looking for the fault that trips an RCD in a PME installation always bear in mind that a Neutral to Earth fault on a circuit whose MCB is opened can trip the RCD. When there is a load on any other circuit connected to the same Neutral bar then the Neutral to Earth short provides a bypass around the RCD sensor for some of the load current.

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

 

[casamena]

When looking for the fault that trips an RCD in a PME installation always bear in mind that a Neutral to Earth fault on a circuit whose MCB is opened can trip the RCD. When there is a load on any other circuit connected to the same Neutral bar then the Neutral to Earth short provides a bypass around the RCD sensor for some of the load current.

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

The rcd does not trip when the mcb is switched off.

 

[bernardgreen]

What I meant was the fault may not be on the circuit controlled by that MCB. It might be a Neutral to Earth fault on another circuit that is diverting part of the neutral current from appliances on the circuit that, when in use, trips the RCD.

 

[ban-all-sheds]

Should you have been doing this?

 

[casamena]

Should you have been doing this?

yes