TN-S SWA Garage Feed

[roys]

Round at my mates place, and we got involved in the old exporting earth discussion which is not the point of this thread honest.

So, his installation was done about 5 years ago, his garage is fed from a 40A breaker on the non RCD of the board. It leaves his CU and goes out to the garage on a 3 core SWA cable, looks like a 10mm from a quick look at the outside size of the cable. In the garage it goes into a 5 way CU which has a RCD protecting all five breakers.

The question he asked over a can of beer is should he change his 40A breaker to a 40A RCBO to protect the cable going out to the garage. The garage is about 20 meters from house and has a water pipe going into it. The house is TN-S and the earth is exported via the 3rd core and armour which is frying panned to bond it together.

Cheers Steve

 

[kme]

No requirement, as long as the cable is SWA all the way. (earthed sheath).

All final ccts are still protected, and an inadvertent spade through the SWA would cause disconnection with 0.4s, assuming the Ze is correct.