22 Nov
2014
22 Nov
'14
5:30 p.m.
On Sat, Nov 22, 2014, at 19:33, Tothwolf wrote:
NEMA 14-30, 240V 30A, 4-wire, clothes dryers
NEMA 14-50, 240V 50A, 4-wire, electric ranges
NEMA 10-30, 240V 30A, 3-wire, clothes dryers
NEMA 10-50, 240V 50A, 3-wire, electric ranges
In the US, with systems installed before 1996, it is common to find NEMA
10 3-wire devices which lack a ground (earth) pin.
And in case anyone's wondering what we need four wires for, it's because
our 240V circuits use two opposite phases that are 120 V relative to
ground. Some appliances will use just one phase for some purposes such
as lights and timers.