NEMA contact ratings

NEMA contact ratings are how much current at a rated voltage a relay or other pilot device can switch. The current rating of smaller NEMA contactors or their auxiliaries are defined by NEMA ICS 5: Industrial Control and Systems, Control Circuit and Pilot Devices^[1] standard. The nomenclature is a letter followed by a three-digit number, the letter designates the current rating of the contacts and the current type (i.e., AC or DC) and the number designates the maximum voltage design values.

AC Contact Ratings

Contact Rating Designation	Thermal Current	Voltage
A150	10	150
A300	10	300
A600	10	600
B150	5	150
B300	5	300
B600	5	600
C150	2.5	150
C300	2.5	300
C600	2.5	600
D150	1	150
D300	1	300
E150	0.5	150

DC Contact Ratings

Contact Rating Designation	Thermal Current	Voltage	Voltamperes
N150	10	150	275
N300	10	300	275
N600	10	600	275
P150	5	150	138
P300	5	300	138
P600	5	600	138
Q150	2.5	150
Q300	2.5	300
Q600	2.5	600
R150	1	150
R300	1	300

See also

• Utilization categories