Blue Sea Systems DC Shunt 500A / 50mV

A Blue Sea Systems DC Shunt is a precision, temperature-stable resistor used as a current "sensor" for DC ammeters — a millivolt meter reads the small voltage drop across the shunt to calculate current, rather than measuring current directly by any other method. This 500A shunt is rated to produce 50mV of drop at its rated full-scale current.

Key features

• 500A rating, 50mV output at full-scale current reading
• Precision, temperature-stable resistance for accurate readings across a wide range of operating conditions
• Two separate screw terminals dedicated to sense leads
• For use with compatible DC ammeters only

The shunt installs directly in the circuit's negative path, in series between the battery and the load, while the meter's sense leads connect to the shunt's two dedicated terminals — those sense-lead connections are strictly for measurement only and should never be used to carry actual load current, since doing so introduces resistance that skews the reading.

Confirm the shunt's amperage and millivolt rating matches what your specific ammeter expects before wiring it in — mismatched shunt ratings are a common source of inaccurate current readings, since the meter's internal scaling assumes a specific mV-per-amp relationship that only holds true for the correct shunt at its rated current.

This 500A rating is one of Blue Sea's most common shunt sizes, frequently included as standard equipment with the manufacturer's own 500A-class digital and analog ammeter products, so a spare or replacement is a straightforward, low-cost item to keep on hand for any DC ammeter installation.