| 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 protection | 125% (See Note 1) |
167% | 300% | Not required | Not required |
| Primary and secondary protection | 250% (See Note 3) |
250% (See Note 3) |
250% (See Note 3) |
125% (See Note 1) |
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.