[Shop-talk] 130v/260v?

[David Hillman]

    I have been curious about this for a while, but unable to find an 
answer online.  My house has standard residential AC electrical service, 
100a at a nominal 120v.  Whenever I put a meter on a circuit, though, I 
always measure about 130v.  Similarly, on the double-pole breaker circuit 
I just installed for my welder (nominally 240v) I measure ~264v.  I have 
used at least three different (cheap) meters, all with similar results.

    Is this highly unusual?  For a given resistance, 264v is going to 
provide about 10% more current than the nominal standard on the 
double-pole circuit.  Is this risky or problematic?  The single-pole 
circuits have been in-place for years, with no apparent problems, but I 
obviously don't want to blow up my Syncrowave.

    Thanks.

--
  David Hillman