Ewan MacIntyre wrote:

Is this cable normal? I suppose my concern is that this particular ring
is quite long, and I understand that steel has a higher resistance than
copper. The ring covers rooms containing mostly lower-powered items, but
does include the washing machine.

I have seen tin-plated copper wire in some older installations; that
looks silver. Are you sure its steel ? Is it magnetic ? If its silver
right through, its probably aluminium, and I personally would remove
every last bit I could find.

Steve