| Period | Evaluation frequency |
|---|---|
| Before December 29, 2003 | At least once every 5 calendar years, but with intervals not exceeding 63 months. |
| Beginning December 29, 2003 | At least once every 3 calendar years, but with intervals not exceeding 39 months. |
|
Code of Federal Regulations
233
|
|
| Device | Check frequency |
|---|---|
| Rectifier | At least six times each calendar year, but with intervals not exceeding 21/2 months. |
| Reverse current switch | |
| Diode | |
| Interference bond whose failure would jeopardize structural protection | |
| Other interference bond | At least once each calendar year, but with intervals not exceeding 15 months. |