| 361 / | HD | ELECTRICITY: ELECTRICAL SYSTEMS AND DEVICES |
| 1 | DF | SAFETY AND PROTECTION OF SYSTEMS AND DEVICES {32} |
| 88 | ![]() | .~ With specific voltage responsive fault sensor {4} |
| 89 | DF | .~.~> With time delay protective means |
| 90 | DF | .~.~> Overvoltage and undervoltage |
| 91.1 | DF | .~.~> Overvoltage {6} |
| 92 | DD | .~.~> Undervoltage |