To reduce the risk of unplanned downtime, the maintenance of a transformer needs to include a regular check of its instrumentation. This includes testing of its temperature and pressure gauges, as well as relays. Dry-type transformers will tend to have less instrumentation, with a focus on temperature variation and surge protection. On all types of transformers, it is vital to regularly test that the probes are accurately measuring the unit’s temperature. Another basic check is the torque measurement on the termination points, to make sure that all connections are tight enough to avoid arcing related to loose connections.