System Voltage in NMEA 2000 – Why you should always choose 12V

Understand why 12V is the safest and most compatible choice for NMEA 2000 installations and how it affects your boat's electrical system.

NMEA 2000 has become the backbone of marine electronics, where everything from sensors to plotters and batteries can communicate on a single network. But when it comes to power supply, there's an important detail that many miss – and which can be costly if done incorrectly.

What does the standard say?

According to the NMEA 2000 standard, the network should be powered with 9–16V DC, which in practice means you should always use 12V as the system voltage. All certified NMEA 2000 products are built to operate within this range. If you connect a higher voltage, you risk damaging both the network and connected devices.

Why are there products that support 24V?

Some manufacturers, such as Actisense and Maretron, have chosen to build their products to handle higher voltage – sometimes up to 24V or more. This can be practical on boats with 24V systems, but it is not according to the NMEA 2000 standard. This means that even if an individual product can handle 24V, other devices on the network could be damaged. Cables and connectors are also often rated for a maximum of 3A and 16V, and higher voltage can lead to overheating and fire risk.

What happens if you run on 24V?

• You risk destroying sensitive instruments and sensors.
• The warranty on NMEA 2000 products may become void.
• The network may become unstable or stop working entirely.
• Cables and connectors can be damaged by overcurrent and heat.

How to do it right

• Always 12V for the NMEA 2000 network! If your boat has a 24V system, use a DC/DC converter that provides stable 12V to the network. There are ready-made adapters for this, for example from Oceanic Systems.
• Always check that all devices on the network are certified for NMEA 2000 and that they receive the correct voltage.
• Install a 3A fuse to protect the network from overcurrent.
• Always connect the network's shield to the boat's ground to avoid interference.

Summary

Although some products on the market can handle 24V, 12V is always the standard for NMEA 2000 networks. It is the only safe way to avoid damage, operational disturbances, and costly repairs. Invest in the correct voltage – and you will get a stable and future-proof network on board.