"dpb" wrote:

I've seen "normal" anywhere from 107V - 130V as pretty common just
depending on where on a line and how far from distribution
transformer a run is. Perhaps not as much variation common in
residential/metro areas that don't cover such long distances w/
individual or very few loads as see out here...

Years ago, NEMA standardized on voltage ratings as follows:

Distribution devices such as transformers and circuit breakers:

120VAC and multiples there of.

Utilization devices such as motors and heating equipment:

115VAC and multiples there of.

The 5VAC differential accomodates line losses and calculation of
loads.

Lew