NMEA 2000 Connector Question

[sailjumanji]

Ok, this should be a simple one, but I thought I would ask before I start cutting cables. I am trying to run a NMEA micro cable inside of an arch on the stern of the boat. The arch is stainless tube, and while I can drill a hole to get the cable to fit inside, the base exit doesn't have enough room for the cable to fit with the connector on. The cable is going to be connected to a GPS antenna on the arch, and the network on the other end. So I have two choices:

1. I have a very long NMEA cable that is bare wire on one end and fitting on the other. I can attach a field-connectable NMEA end fitting, but I have heard of people with issues getting them to work.

2. Second choice - which seems to be simple, and I don't have to wait on parts - is to just cut a pigtail off of another cable and then just splice together each of the identical color wires.

Is there any reason that either of these would not work? Or one better than the other. The splice would be inside the boat, in a dry area.

Hoping for some input before I cut cables tomorrow. I already drilled into the electrical wires coming from one of the solar panels, which is now giving me the excuse to pull larger gauge wire as the replacement!

Mike

[Ziggy]

Installing field-installable NMEA2k micro connectors isn't all that difficult, as long as you have the patience for putting 5 tiny wires into 5 tiny holes all at once without some of them coming out before you tighten the tiny screws. Check the connections with a multmeter before you put your tools away and be prepared to take it off and do it again if it's not right. All in all, it shouldn't take more than about 15 minutes.

[NahanniV]

I have done both, either will work if you do it carefully.

My Garmin NMEA2000 wind transducer came with a field install-able connector:
Tin the wires, I needed some magnifying glasses and patience to get it all together.

I also spliced a NMEA2000 cable to a SeatalkNG cable without problems: get small heat shrink tube, butt splice and solder each wire with rosin core solder, then shrink tube, then larger seal wall shrink tube over the whole bundle. It worked fine and even looked good.

Cheers,
JM.

[continuouswave]

While most NMEA-2000 network wiring is done with connectors, that is mainly for convenience, and the connector or its form is not really part of any electrical specification. NMEA-2000 network connections can be made on terminal strips.

There is generally no problem at all in making a splice connection in a NMEA-2000 cable. I have made several custom cables this way by using pre-made connectors that are molded onto a cable, cutting them in half, and splicing two segments together to make a custom cable with different connectors on each end.

I recommend you make the spliced part of the cable somewhere in a weather-protected area.

[sailjumanji]

Thanks for the input and advice. Really appreciate it.

[captmikem]

NEMA2k is low voltage low freq, so no problem splicing it. I find gel phone splice connectors to be easy, water resistant/proof, and lasting.. plus they are inexpensive. I like 3m scotchlock best, but several companies sell them. I use them a lot. you can buy the tool for them or use a pair of pliers, just listen for the snap.

amazon has them, just look under "phone splice".

Michael

[transmitterdan]

NMEA 2000 is low voltage but it is not low frequency. A crummy splice can cause data errors. Try to keep the splices as short and close together as possible without shorting. There are tiny terminal blocks that work well. Check at mouser.com or digikey.com.

[CarinaPDX]

Either way works fine if done carefully; personally I use the field-installable connectors. One thing to keep in mind is that opposite ends of the cable are not identical in the order of the wires as they enter the connector (they are mirrored). So put on one end the wires will come out in the same order as the terminals in the connector, and on the other the wires will have to be crossed to match up with the same connector. Which is to say that one end will fit nicely the male connector and the other the female connector, but reversed will be a mess. A small detail, but worth watching...

Greg

[Dragonfly238]

I seem to be very challenged with this. I am installing an engine monitor so that I can see engine date on my multi-function screen. Having read this thread, I plugged everything in, checked that it all worked. Then cut off the pigtail, threaded the cable through the nooks and crannies required.


I've now re-done the connector three time, my wire stripping and tinning are works of art after so many goes at it, but I cannot get the field connector to work.



What could I be missing? (Will test with my multi-meter tonight, but I can't see anything obvious)

[Tillsbury]

I find it much easier and more reliable to join two cable ends than use the field-installed connectors. Visually checking the connections is way easier. Keep them nice and short and get as much shielding back over the top as you can.

[sailjumanji]

Can you use your continuity setting on your multi meter to check? Thats what i did to confirm all good.

[Tillsbury]

A continuity tester will show you a complete failure, but you can get a connection good enough to pass that but still cause problems with high frequency data. We used to get this all the time back in the day when computer networks were built on site. Cleanliness, care, and good visual inspection is the key to getting reliable data connections. There's no real point in a continuity tester as if it fails with one of those you just weren't concentrating nearly enough when you were making the connection.

[Dragonfly238]

Originally Posted by Tillsbury

A continuity tester will show you a complete failure, but you can get a connection good enough to pass that but still cause problems with high frequency data. We used to get this all the time back in the day when computer networks were built on site. Cleanliness, care, and good visual inspection is the key to getting reliable data connections. There's no real point in a continuity tester as if it fails with one of those you just weren't concentrating nearly enough when you were making the connection.

Well, having built coax/BNC, ethernet and EOP networks earlier in my career, that's kinda what I was thinking. (I used to be an IT trainer in a previous life)


At least a multi-meter will show a complete failure, but I don't expect a complete failure.


On the upside, my tinning and soldering skills have improved

[sailjumanji]

Continuity tester also confirms you put the right wire in right socket.

[Dsanduril]

Just came across these self-soldering heat shrink butt splices in my business life. Splice/solder/heat shrink all in one unit, using only a heat gun. No mechanical connection however. Seem to work well on land, anyone actually used them on a boat? Seems like they might be useful in this scenario.