Blue Sea Systems AC Current Transformer, For AC Ammeters, 50mA AC Output, 0.60in ID, 1.38in OD

Overview

This Blue Sea Systems AC current transformer is a coil-style current sensor used with AC ammeters to monitor current on a boat AC electrical system. It steps the measured primary AC current down to a 50mA AC signal that the matching meter can read, making it useful for shore power panels, inverter-fed AC panels, generator circuits, and other onboard AC monitoring points.

The range includes 50A, 100A, and 150A AC versions. Each confirmed model uses a 0.60 in inside diameter opening for the conductor and a 1.38 in outside diameter body, so it can be planned into panel wiring where space and cable routing matter.

Key features

• For use with AC ammeters in marine electrical monitoring installations.
• Available in 50A AC, 100A AC, and 150A AC primary ranges, each with a 50mA AC output.
• 0.60 in inside diameter allows the measured conductor to pass through the coil.
• 1.38 in outside diameter helps the coil fit into many AC panel and meter wiring spaces.
• Useful for monitoring AC load current from shore power, generator output, inverter output, or branch circuits when paired with the correct meter scale.
• Passive coil format keeps the sensing point simple, with the ammeter handling the display and scaling.

Variants

This product is offered in multiple current ranges so the transformer can match the ammeter scale and the expected AC load on the circuit being monitored.

The output ratio changes by variant, while the verified body dimensions are consistent across the range at 0.60 in inside diameter and 1.38 in outside diameter.

• 8073: 50A AC/50mA AC ratio. This version fits lower-range AC ammeter installations where the monitored circuit is scaled around a 50A primary current.
• 8257: 100A AC/50mA AC ratio. This version matches AC ammeter setups that read a 100A primary range through a 50mA coil output.
• 8256: 150A AC/50mA AC ratio. This version is used where the meter and circuit are set up for a higher 150A AC primary range.

Installation and setup

Install the current transformer around the AC conductor being measured, then connect the coil leads to a compatible AC ammeter input. The meter must be matched to the transformer ratio, because a 50A, 100A, or 150A coil will display correctly only with the correct ammeter scale.

During panel work, keep the coil close to the meter wiring path and avoid routing it where service access will be difficult later. On boats, it is also worth checking that the conductor bend radius, strain relief, and panel clearance leave enough room for the coil body before closing the panel.

Compatibility and fit

This current transformer is a practical match for boat owners and installers adding or replacing AC current monitoring on a marine electrical panel. It is most relevant when the vessel already uses, or is being upgraded to use, an AC ammeter that accepts a 50mA transformer signal.

The key fit checks are the circuit current range, the ammeter scale, and the conductor size through the 0.60 in opening. It is not a standalone display, breaker, or protection device; it is the sensing coil that allows the ammeter to read current safely from the monitored AC conductor.

Safety note

This product carries a California Proposition 65 warning for DEHP. AC electrical work on a boat should be handled with the circuit de-energized and checked by a qualified marine electrician when the installation involves shore power, inverter output, generator wiring, or main AC distribution equipment.