What's this little cable for??? (with pics)

[lazygit]

Is the wire actually any use Coljack?

I have this type of RCD at my house and tested with and without the wire connected. The trip times were identical.

As you say there may be voltage on the earth and is monitored by this type of RCD, but if the leakage current did not originate from the source supplied by the RCD, then even if the it trips there will still be voltage present on the earth.

 

[bernardgreen]

Question

Under regulations does the earth lead on this RCD go to the protective earth ( CPC ) or to true earth as in ground ?

Reason for asking is that if it is taken to true earth then it would detect and trip on a floating neutral of a system such as PME where the protective earth is derived from the incoming neutral.

 

[Spark123]

I'd have thought it goes to the earthbar in the CU which is connected to the MET.

 

[JohnD]

that's right. the one illustrated is from the range of CU devices.

(it is actually an A100MET)