Blue Sea Systems DC Analog Meter Shunt, 50mV Full Scale

Overview

The Blue Sea Systems DC Analog Meter Shunt is a 50 mV full-scale shunt range for use with DC ammeters on marine electrical systems. It lets an analog ammeter read DC current by measuring the small voltage drop across a known resistive element, so high-current battery, charging, and distribution circuits can be monitored without routing full load current through the meter itself.

This range covers 50A, 75A, 100A, 150A, and 200A ratings, with small-base versions for the 50A through 150A sizes and a large-base version for the 200A size. The shunts use a resistive manganin metal element, have a 50 mV full-scale output, and are rated for continuous operation at 66% of the stated current under normal conditions.

Key features

• 50 mV full-scale output for compatible DC analog ammeters.
• Rated current options from 50A to 200A to match the monitored DC circuit and meter scale.
• Continuous-duty guidance of 66% of rated current for normal operation.
• Intermittent-duty capability of 300% for 3 seconds and 100% for 5 minutes.
• Resistive manganin metal element for stable current measurement in DC monitoring applications.
• Small-base and large-base options give installers a way to match the shunt size to the current rating and mounting space.

Variants

This DC analog meter shunt range is offered in multiple current ratings and base sizes. The main differences between the configurations are the rated current and the physical base size.

The 50A, 75A, 100A, and 150A versions use the small base, while the 200A version uses the large base. All listed variants are 50 mV full-scale shunts for use with DC ammeters.

• 9228: 50A rated current with small base. This version suits lower-current DC monitoring points where panel space and mounting area are limited.
• 9233: 200A rated current with large base. This version is the higher-current option in the range and uses the larger base for its 200A rating.
• 9230: 100A rated current with small base. This version fits mid-range DC ammeter installations where the monitored circuit and meter scale are based around 100A.
• 9229: 75A rated current with small base. This version sits between the 50A and 100A options for systems that need a 75A shunt scale.
• 9231: 150A rated current with small base. This version supports higher-current DC monitoring while staying in the small-base format.

Installation and setup

The shunt should be installed in the DC circuit being monitored and paired with an ammeter that matches the shunt rating and 50 mV full-scale signal. Current rating matters: the shunt, meter scale, conductor size, and circuit protection should all make sense together before installation.

For normal continuous use, size the installation so the shunt is not operated above two-thirds of its rated current. That gives the electrical system a practical margin for charging loads, inverter draw, windlass use, pumps, electronics, and other onboard DC loads that may vary during use.

Use cases on board

These shunts are a good match for boat owners, electricians, and refit projects that use analog DC ammeters to monitor battery banks, charging output, distribution panels, or other DC loads. They are especially useful where the helm or panel meter needs to show current flow while the high-current conductors remain routed through the proper electrical space.

The small-base versions work well where current requirements fit the 50A to 150A range and mounting room is tighter. The 200A large-base version is better suited to higher-current monitoring points where the larger shunt rating is required.