[Patrick Turner]

Snip,


With current line voltage being 120VAC a 2.6%, so called, 'creep' over
70 years hardly strikes me as a 'problem', especially since it isn't
really an operational creep as modern tolerances, generally +-5%, are
tighter than in 1940.

What may be the cause of the, so called, 'creep' notion is observing,
as you have done, socket voltage. Reason being, power companies like
to operate on the high side of the range for the obvious reason it's
downhill from there. I.E. You're not going to have more than what's at
the entry and then you have internal line losses. Second, the power
company believes a higher voltage is more efficient because of lower
current, for the same power (disputable), hence lower line losses. At
any rate, with tighter regulation one can operate closer to the
tolerance max (same reason nominal 'crept up' from 117VAC to 120VAC)
but the 120VAC nominal spec hasn't change for many decades.

Point is, simply observing 125VAC on your wall outlet doesn't mean the
'line voltage' spec has 'crept up' as it's still within the 120VAC
nominal +5%.

Having multiple devices connected to the mains and all with diode
rectifiers feeding cap inputs of linear supplies or SMPS dtends to
create a mains wave which is triangular with flat tops, ie, a high 3H
harmonic content.

Power companies are in the business of making profit selling power. So
if they raise Vmains, then mains current increases to the power
consumed tends to increase and the power company profits with no
additional costs to its transmission lines.
Its like water pressure, the higher t is the more ppl use, and up go
profits. To reduce water usage in times of drought and falling dam
levels the comanies have tried reducing water pressure which
significanly reduces water usage. The same idea is not able to be
applied to electricity because a mains drop of say 30% would make many
things fail to function properly including medical and military and
communications stuff.

snip,

A good and serious manufacturer should have built his
equipment with proper VAC input settings in order to accomodate
variations anywhere in the entire world .

That's a wonderful sounding notion but you can't design for "anything
someone might do." You can only design to a SPEC and it isn't
necessarily 'worth it' to sell your product 'everywhere'.

ARC could very easily to accomodate a wide range of mains voltages.

It would be a major improvement to their product which would increase
sales.

Patrick Turner.