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.
| 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
|
| 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 |
|
