Recommended checks before CU change

Fitzy71:

Zoomup:

Fitzy71:

When these boards were installed, would the neutrals be in the same numerical order as the fuses are laid out, or was it just hit & miss in those days?

The neutrals should be in the correct order relating to the lives, BUT very often are not. If the whole T&E cable can be seen than identification is easy, but if just singles appear that can create i/d problems. The different cable sizes can also help to identify likely suspects. I have been known to turn off and double check disconnection, lock off and temporarily connect a 9 Volt smoke alarm battery to a circuit and test at the consumer unit with a Volt meter to identify cables. All loads must be disconnected of course or they will just short out the battery.


Z.

 

Am I right in my thinking that the ring final/radial circuits might be in imperial sizes and the cpc could be 1mm2 instead of 1.5mm2?

 

Fitzy71:

Zoomup:

Fitzy71:

When these boards were installed, would the neutrals be in the same numerical order as the fuses are laid out, or was it just hit & miss in those days?

The neutrals should be in the correct order relating to the lives, BUT very often are not. If the whole T&E cable can be seen than identification is easy, but if just singles appear that can create i/d problems. The different cable sizes can also help to identify likely suspects. I have been known to turn off and double check disconnection, lock off and temporarily connect a 9 Volt smoke alarm battery to a circuit and test at the consumer unit with a Volt meter to identify cables. All loads must be disconnected of course or they will just short out the battery.


Z.

 

Am I right in my thinking that the ring final/radial circuits might be in imperial sizes and the cpc could be 1mm2 instead of 1.5mm2?