Overview

The Hella Marine 007793031 is a 12 V, 4-pin Mini ISO power relay with a normally open (SPST/Form A) contact and built-in resistor coil suppression. It is rated at 50 A and carries an IP54 protection rating, making it a practical choice for switching higher-current DC loads from a low-current helm switch, keypad, or control module.

On a boat, this type of relay is commonly used to keep current out of the dash and shorten the high-amp wire run by placing the relay closer to the load or the distribution point. The resistor coil suppression helps tame switching spikes, which is useful when the relay is triggered by electronics or long control-wire runs.

Key features

• 12 V coil for 12 V DC marine electrical systems
• SPST/Form A normally open contact for straightforward on/off control
• 50 A current rating for many accessory and utility circuits
• Mini ISO footprint with 4 blade terminals for common relay sockets and fuse/relay panels
• Resistor coil suppression to reduce voltage spikes when the coil is switched off
• IP54 protection rating with a dust cover, suited to protected mounting locations

Installation and wiring

Plan the install so the relay sits in a relay box, electrical locker, or other protected area, not in a bilge space or anywhere it can be soaked. Use a proper relay socket or holder so the terminals are supported and the relay cannot work loose from vibration.

Size the fuse or breaker and wire gauge for the load you are switching, not for the control circuit. Keep the high-current feed protected close to the power source, and secure wiring runs so they do not chafe. Before crimping, confirm the terminal markings on the relay body and match them to your wiring diagram.

Compatibility and fit

This relay uses the Mini ISO 4-pin blade layout found in many relay/fuse panels and marine distribution builds that borrow standard automotive-style relays. It is intended for 12 V control voltage, so it is not a drop-in choice for a 24 V coil circuit.

On-board use cases

This relay is a good match for switching loads such as deck and spreader lights, horns, small pumps, fans, or an accessory bus feed, where you want the helm control to carry only a small trigger current. It also fits well in refits where a standard 4-pin Mini ISO relay socket is already in place and you need resistor-suppressed coil switching.

Maintenance and care

In saltwater environments, protect terminals from corrosion with a sealed relay box where possible, clean crimps, and heat-shrink insulation. Periodically check for warmth at the socket and for discoloration at the terminals, both of which can point to a loose connection or an undersized wire run.