Common in many substations are oil filled circuit breakers. Typical of this type is the Westinghouse 345 kV unit shown in Figure 1.
There are usually two common leaks on OCB’s that TDS has repaired in the past. The most common leak is a drain valve leak, See Figure 2. Drain valves are repaired exactly the same way as on transformers. Usually OCB drain valves leak at the valve hex end to the threaded pipe nipple. This leak is always repaired with a clamp. Drain valve stems can be repaired using the drill and inject method.