All NEMA 6 devices are three-wire grounding devices
(hot-hot-ground) used for 208 and 240 V circuits and rated for 250
V maximum, with the 6-15, 6-20 and 6-30 being grounding versions of
the 2-15, 2-20 and 2-30, respectively. The 6-15 resembles the 5-15,
but with collinear horizontal pins, spaced 23/32 in (18.256 mm)
center-to-center. The 20 A plug has a blade rotated 90C, and the
6-20R receptacle may have a T-shaped hole, to accept both 6-15P and
6-15R and 6-20R receptacles are usually manufactured on the same
assembly line as "Industrial" or "Commercial" grade 5-15R and 5-20R
receptacles, with all 4 receptacles sharing the same "triple wipe"
T contacts behind the varying faceplates. The faceplate bonded onto
the receptacle determines the final configuration of the
The 30 A plug and socket look similar to the 15 A one but larger.
The higher-current versions are rare, with twist-locking plugs such
as L6-30 or direct wiring more common. Generally 6-series
non-locking plugs are used for such appliances as large room air
conditioners, commercial kitchen equipment, and the occasional home
Single-phase 6-50 is commonly used on farms for silo unloaders, and
is used with a 6-gauge flexible power cord up to 200 ft (61 m)
long. Some manufacturers of electric vehicle charging stations
equip their 30-40 A Level 2 EVSEs with a 6-50 plug on a short cord,
though it is becoming less common, with manufacturers now favoring
the more common 14-50 plug.
NEMA 6 devices, while specified as 250 V, may be used for either
208 or 240 V circuits, generally depending on whether the building
has a three-phase or split-phase power supply, respectively. The
NEMA 6-20R or 6-30R found in many hotel rooms is typically supplied
with three-phase 208 V.