| 700 / | HD | DATA PROCESSING: GENERIC CONTROL SYSTEMS OR SPECIFIC APPLICATIONS |
| 90 | DD | SPECIFIC APPLICATION, APPARATUS OR PROCESS {16} |
| 286 | DD | .~ Electrical power generation or distribution system {5} |
| 292 | DD | .~.~ System protection (e.g., circuit interrupter, circuit limiter, voltage suppressor, etc.) {2} |
| 293 | | .~.~.~ Abnormal power, current, or impedance condition |