Specific to data center use cases, Residual Current Monitoring, frequently abbreviated RCM, is a type of data center monitoring that detects residual current. Residual current, also known as differential current, occurs when the current going into a circuit and the current going out of the circuit are imbalanced. Ideally, these two measures should be equal. In a perfectly functioning circuit, the residual current is zero.
Residual current is usually caused by leakage or faulty insulation. This is why residual current is sometimes called leakage current. Residual current monitoring looks for current that has “leaked” outside of a circuit, creating a potentially dangerous environment, as well as wasting energy.
Residual current monitoring is not only critical for the safety of your data center, but it can also help you ensure data center uptime by enabling you to identify and correct issues before they create bigger problems. Reducing leakage through residual current monitoring also improves data center energy efficiency.
RCM can also refer to residual current monitors, devices whose purpose is to monitor residual current. Many intelligent PDUs have RCM modules, so an external device isn’t required. Other types of residual current monitoring devices include RCDs (Residual Current Devices) and GFCIs/RCCBs (Ground Fault Circuit Interrupters/Residual Current Circuit Breakers).