In the main panel, there are 3 wires for 3 phase power going from 3 pole 40A breaker to a sub panel. the breaker is (CKIPSAL 4CB340/6 C40) The wires are in 2 cables.
Each of these wires has 7 strands 19 SWG each. Online search reveals that 19 SWG handles 4.13amp. which tells me that the wire is expected to handle 29amp (7 x 4.13)
If the breaker should protect the wire, then why it is 40amp when the wire is 29amp? i.e. I expected to see the breaker amp less than the wire amp rating.