Originally Posted by

**vw55**
I've always understood that kwh is actually a combination of units from two different unit systems, the SI unit is watt and the standard English unit is hour . . . .

A “watt” is indeed an SI unit (i.e., metric). Its fundamental units are:

1 watt = 1 (kilogram) (meter squared) / (second cubed).

The basic unit of measure for time is the second, both in SI Units and in English Engineering Units.

Originally Posted by

**vw55**
. . . and there was no direct conversion from kwh to kva that can occur.

There cannot be a “direct conversion” between KWH and KVA. They are different parameters. It is like trying to get a direct conversion between MPH (miles per hour) and feet.

Your process of deriving KVA from KWH, a process that requires knowing two other parameters (time and power factor) is valid.

Charles E. Beck, P.E., Seattle

Comments based on 2008 NEC unless otherwise noted.

## Bookmarks