Why are external shunts sometimes used with ammeters?

Correct Answer: Option B — to prevent damage to the meter movement from heat generated by the internal shunt

External shunts keep high thermal dissipation away from delicate meter movements. According to IEEE 45 guidelines for switchboard instrumentation, locating the resistive element externally prevents temperature-induced calibration errors and prevents thermal damage to internal moving coil assemblies during prolonged current monitoring.