Charger cables have built in fault and overheat detection circuitry with sensors built into the 13A plug. If they find anything wrong, they shut down the charge.
While it’s correct that a good cable does work, this is incorrect – and in fact one of the main reasons stated as to why extension leads are “suboptimal” even if you get a proper cable.
The issue is the wall outlet. By using an extension cable you disable the overheat detection, since obviously the granny charger can’t wirelessly measure the socket at the other end of the extension cable. So, no. You actually don’t have overheat protection when using an extension cable. Fault protection should still work i assume, though.
Prior: SEAT Ateca Xcellence Lux 1.5 TSI DSG MY19, VW Golf GTE PHEV DSG MY23
Current: Hyundai Ioniq 6 Ultimate
Next: we'll see what's available in 2028.