Maretron CG1-40 Micro Bulk Cable, 40 Meter NMEA 2000 (Gray PVC)

Maretron's CG1-40 is 40 meters of Micro bulk cable on a single continuous run, and it's the piece most boaters reach for when a pre-made cable just won't fit the boat. Instead of stringing together a handful of fixed-length jumpers, you cut exactly what you need and put a field-attachable connector on each end. Clean runs, no coils of extra cable stuffed behind the helm.

This is the same Micro cable that carries an NMEA 2000 network. Gray PVC jacket, rated at 6 amperes, and it can serve as either your backbone (the trunk) or a drop line down to an individual device. On most boats under 40 feet, 40 meters is plenty to run a full backbone from bow to stern with room left over for drops. We've pulled this stuff through some tight gunwale chases, and the jacket holds up well once it's warmed up and flexible.

Here's why the bulk approach wins on a real install. Say your backbone needs 6.4 meters between two tee connectors and the drop to your depth transducer is 1.8 meters. No stock cable matches those numbers. With bulk cable you measure the actual path, add a little slack for strain relief, cut, and terminate. The network ends up neater and every foot of cable is doing a job.

A word on the field-attachable connectors, because that's where most trouble comes from. You'll need Maretron field-attachable Micro connectors (sold separately) to finish each cut end. Take your time on the assembly. Line the pins up carefully, seat the gland, and use a dab of dielectric grease on the seal so water can't wick in later. A rushed connector is the number one reason a field-built cable throws intermittent faults down the road. Do it right once and it'll outlast the electronics it feeds.

Keep the power budget in mind on longer runs. Six amps is plenty of headroom for a typical network, but voltage drop adds up past 25 meters or so, especially if you've got several displays and a couple of hungry sensors all pulling from the same segment. If you're building a big backbone, plan your power tap near the middle of the run rather than at one end. And remember a backbone needs a terminating resistor at each far end. Two terminators, no exceptions, or the whole network gets flaky.

Who's this for? Anyone rigging or re-rigging an NMEA 2000 network who's tired of compromise lengths. Installers love bulk cable for exactly that reason. First-time owners doing a careful DIY job can use it too, as long as you're comfortable assembling a field connector and willing to go slow. If you just need to connect two devices a known distance apart and a stock cable happens to match, a pre-terminated cable is simpler. Bulk cable pays off when your lengths are odd or your run is long.

On the approvals: this cable is NMEA 2000 Approved, UL Listed, CSA Certified, and meets IEC-61162-3. That matters more than it sounds. Certified cable is built to a known impedance and shield spec, so your network data stays clean and your surveyor and insurer stay happy. Cheaper uncertified wire can pass data on the bench and then cause headaches once it's buried in a noisy engine room.

Bottom line: if you want a network that fits your boat instead of the other way around, buy the length you need in bulk and terminate it yourself. The CG1-40 gives you 40 meters to work with, which covers most single-run backbones and still leaves plenty for drops. Label each end as you go, coil the leftover neatly, and you've got a tidy, certified network you can actually service later.