Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

RCMResidual current monitor: original educational illustration
Symbols

Residual current monitor

A residual current monitor measures residual current with a summation toroid around the circuit conductors and signals when it exceeds a threshold. It is used where an unexpected trip would be unacceptable but rising leakage still needs attention, for example in data centres and process plant.

Drawing use
SLD / Schematic
Application
Metering & protection
Reference family
IEC / Manufacturer

A distinction that matters

An RCM signals residual current; an RCD measures it and also disconnects the circuit.

Full reference
CBCTCore-balance current transformer: original educational illustration
Symbols

Core-balance current transformer

A core-balance CT measures residual current from the net magnetic effect of conductors passing through its window. It is used with earth-fault protection where the conductor arrangement and sheath routing affect the measurement.

Drawing use
SLD / Schematic
Application
Metering & protection
Reference family
IEC / Manufacturer

A distinction that matters

A CBCT measures a combined residual quantity; a phase CT measures an individual conductor current.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.

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