Building wiring code NEC requires conductors in a circuit to run in the same cable or raceway, so despite the loop nature inherent to a circuit the wiring has essentially a tree (DAG) topology in space. The loop area enclosed by a circuit wired this way is essentially the distance between conductors times the length of the cable. In Europe they do something similar except they got smart and decided it was okay to connect two branch circuits together at the ends, allowing current to flow in both branches to power any appliance on either. This "ring circuit" configuration reducss wire size and voltage drop, but is subject to partial failure where an open fault forces all current through a single branch. This causes additional heating with no obvious sign something is wrong. A ring circuit also has significant area enclosed in loops made of conductive material. I'm not a physics expert but it seems to me that allowing additional environmental magnetic flux to pass through your circuit (flux=BAcosθ where A is area), could heat those conductors and cause a fire. So maybe IEC coded buildings will burn first when this happens again.