Just sitting here on night watch, and thinking about what you're going
through with this sub-mains cabling.

I'm now going back 30 years, to the time when we had to pull through a
galvinised pipe and connect up to an old knife and fork, side lever,
individually fused phase and neutral box. If the head end was 100 amps you
could only give 80 amps sub-supply, with cartridge fuses in the knife and
fork box. The earth provision was the gun metal pipe, with wrappings of
copper pulled tight around the outside of the pipe with a twist clamp and
your conductor tucked neatly underneath it. Then you had to make sure that
you made off the pipe ends to stop chaffing on the insulation, and the ends
had to be threaded back to allow for a ferrol and have two lock nuts before
the end ferrol, to stop it shaking off.

There was no SWA cable back then, and no screw on glands to make things
easy, so everything had to be piped and clamped and welded. What a lazy
effin lot you are now. :-)

Can still remember my first time in a new sub-station erection. Was
literally pooping meeself. Had to make off for a new build project, with 6
X 2 inch (50 mm) phase supplies to three housing estates. We had to provide
14 grounded points within the sub-station, and two grounded neutral
equalisers. Both equalisers alone where 2 foot diameter and had to be
buried to 12 feet. Stuffed if the ground was solid, but it had to be done.
They were tested with a hammer and stethoscope to see if they vibrated to
much.

If you've ever watched a 1 inch thick (25 mm) brass alloy bar, quite
literally, dissolve before your very eyes, because you didn't follow
instructions properly, then you know how difficult to balance all this was.
We didn't have regulated supplies to the stations back then. So things
could come in at all angles and phase potentials. Come to think about it,
it was bloody dangerous for us workers back then.

But, when your journey man tells you to throw the switches and everything
buzzes into life. What a feeling. I couldn't take the grin off my face for
weeks. All the hard work just melts into the ether and the jobs a good 'un.
I even got to peel the backs off those new fangled self adhesive signs. OK,
I bubbled a couple on the first go, but got to do them again, properly that
time.

Now I go equipped with a roll of SWA and a couple of boxes. Fix it all to
the wall and make the ends off. WOW!!! What a lazy barsteward I am as well
now. :-) The changes in just that short space of time are amazing. It is
safer and more efficient now-a-days, than it was then. It is more basic now
than then as well. With equalisation (potential bonding) done around the
final circuits instead of grounding to the supply. What a difference it is
in safety, and you new guys don't realise that.

Breakers that work with a little coil wrapped around a ferrite rod, that
activates another smaller coil wrapped in close quarters around the same
ferrite rod. Coils wrapped around ferrite rods were used as radio aerials,
way back when I was a lad. :-) Little bits of bendy alloy that push a
plunger to release a spring and cut the circuit? What ever happened to the
big mouse trap handle and melting wire? LOL

So, what's the problem with your sub-mains supply? :-)