On Sun, 19 May 2013 08:58:34 +0100, N_Cook wrote:

800 watt toroidal transformer operating at say 400 watts. Secondaries
lead to conventional bridge rectifier and smoothing caps for +/- rails.
A break appears in the DC rails central 0V return to the transformer,
could that lead to a blown mains fuse, via inductive action?

Intermittent contacts within inductive circuits can be disastrous.
Hail to the fuse for being fast enough.

Cheers!