| Primary Protection | Secondary Protection | ||||
| Protection Method | Currents of 9 Amperes or More | Currents Less Than 9 Amperes | Currents Less Than 2 Amperes | Currents of 9 Amperes or More | Currents Less Than 9 Amperes |
|---|---|---|---|---|---|
| Primary Only | 125% |
167% | 300% | Not required | Not required |
| Primary & Secondary | 250% |
250% |
250% |
125% |
167% |
| Primary Protection | Secondary Protection | ||||
| Protection Method | Currents of 9 Amperes or More | Currents Less Than 9 Amperes | Currents Less Than 2 Amperes | Currents of 9 Amperes or More | Currents Less Than 9 Amperes |
|---|---|---|---|---|---|
| Primary Only | 125% |
167% | 300% | Not required | Not required |
| Primary & Secondary | 250% |
250% |
250% |
125% |
167% |
3Ø or 1Ø, Phase
Transformer Size, "KVA"
Primary Voltage, "PL-L"
Secondary Voltage, "SL-L"
Note: NEC 240.4(C) Where the over current device is rated over 800 amperes, the ampacity of the conductors it protects shall be equal to or greater than the rating of the overcurrent device defined in 240.6.