Hi!

I am struggling with an argument about a couple of damaged home
computers and I was wondering if anyone can help????

I'll give you my thoughts and personal experiences. That's all I can do.

Their electrician said that the switchboard was a 30 year old
porcelain-fused model and was burning out on the busbar and the
circuits on the board were overloaded with too many appliances.

An overload causing failure of said switchboard is entirely possible. But
for a model that was only 30 years old? I don't think I can say that.
Instead I believe that the panel may have been wired incorrectly and perhaps
severely overloaded or used in a way that was not intended. Maybe it was
also a poor quality service panel?

I have here electrical components in use on a 60 amp system. Electricity
comes into my home via a box made in February of 1938 and rated for 60
ampere service on each phase of the 110V coming into my home. There are
pieces of wiring that are older than that and some that are much newer. (For
example, I recently redid the wiring in an entire basement room and used
modern-day equipment to rewire it.)

Other than places where mistakes were made or thinking simply wasn't done,
this electrical system has and continues to serve me well even with very
modern loads like central air, lots of computers and other heavy loads on
the wiring. As long as I've maintained said wiring and kept terminals and
contact points cleaned up, I have experienced no problems and have no reason
to worry about my electrical system.

My question to you, if you would be so kind...."What chance is there
that the slightly under supply of grid voltage would severely damage
pcs, or, is the pc damage more likely to be as a result of the arcing
at the switchboard?"

Either of these could cause damage. Enough momentary current fluctuations
could wear down the filter capacitors in the average PC power supply and
eventually cause a failure. So could enough continued brownouts. It would be
hard to tell exactly where the failure occured.

William