Sigma MCCB curve

Indeed there is not much point in a wire armour unless it is earthed to something that will pop the ADS in someway.  Even a garden fork is capable of separating the strands on smaller SWA, let alone anything more agricultural. You'd not like that to stay live all day.

However I presume this is 35 or 50mm2 cable so fairly tough.

A fault loop of 0.22 ohms (ISC of  what - about 1kA-1,1kA ?) seems a bit high for a 200A breaker, especially one that needs 10 to 12 times the 200A depending on the model chosen to be sure it will trip promptly.

If it does not go in 5 seconds it may go in 10-20...

Mind you , on a TNC-s supply,  that impedance will be similar for the L-N loop as well and so that also suggest up to 20% voltage drop at 200A load so perhaps something in the supply is a bit undersized (well over-long and/or too thin), or the breaker a bit on the large side for what it is meant to protect. Or the test result is a bit off.

 In many ways a fuse may have been better, and I think you are right to raise at least a  curious eyebrow and perhaps to request an explanation.

Mike.

Indeed there is not much point in a wire armour unless it is earthed to something that will pop the ADS in someway.  Even a garden fork is capable of separating the strands on smaller SWA, let alone anything more agricultural. You'd not like that to stay live all day.

However I presume this is 35 or 50mm2 cable so fairly tough.

A fault loop of 0.22 ohms (ISC of  what - about 1kA-1,1kA ?) seems a bit high for a 200A breaker, especially one that needs 10 to 12 times the 200A depending on the model chosen to be sure it will trip promptly.

If it does not go in 5 seconds it may go in 10-20...

Mind you , on a TNC-s supply,  that impedance will be similar for the L-N loop as well and so that also suggest up to 20% voltage drop at 200A load so perhaps something in the supply is a bit undersized (well over-long and/or too thin), or the breaker a bit on the large side for what it is meant to protect. Or the test result is a bit off.

 In many ways a fuse may have been better, and I think you are right to raise at least a  curious eyebrow and perhaps to request an explanation.

Mike.