Moderated Discussion Areas
ContinuousWave: Small Boat Electrical
Connecting Small Gauge Stranded Wires
|Author||Topic: Connecting Small Gauge Stranded Wires|
posted 03-13-2011 03:21 PM ET (US)
I would like to connect my DSC-capable VHF marine radio to my GPS chart plotter via their respective NMEA-0183 connection points. Each provides a two-wire pigtail for this purpose, but they are not long enough to reach one another. What would be a good way to extend the wires and join them, ideally in a way which could be disconnected without difficulty? I'm very comfortable with most wiring tasks, but the small gauge of these wires concerns me.
posted 03-13-2011 04:41 PM ET (US)
I used and RJ11 plug and connector. See this thread:
posted 03-13-2011 07:13 PM ET (US)
Use of a plug and connector sounds like a good bet for you. If you don't care for that solution I believe Maretron (sp?) at maretron.com sells NMEA compliant waterproof junction boxes for splicing NMEA 0183 or 2000 cables. They are popular for joining lengths of sounder transducer cable.
posted 03-13-2011 09:41 PM ET (US)
The Switchcraft QG TA-series mini-XLR connectors may be good for this. I am thinking about wiring my VHF Marine Band radio interface to one, and with a mating connector wire my GPS receiver and chart plotter (in one unit). That way I could remove either the radio or the GPS receiver-chartplotter from the boat just by disconnecting the mating connectors.
posted 03-14-2011 07:51 AM ET (US)
I use Euro Terminal Strips purchased at Radio Shack.
Here's the install on my 210 Ventura. I used 18 awg wire to extend the NMEA 0183 connection from my Furuno 620 to Garmin 740.
They are easy to install and maintain.
I've been using this method for years and never had any connection failures.
posted 03-14-2011 12:13 PM ET (US)
I used Radio Shack EURO strips for interconnecting my house speaker system with a multichannel amp. They work great and you cannot beat the price. It had not even occurred to me to use them in the boat until reading Tom's post.
posted 03-14-2011 06:16 PM ET (US)
The only reason I chose to use an RJ connector over the terminal strips was wire gauge. The wire is, as I said, ridiculously small.
The terminal strips work by using a screw on top of a thin, steel blade; advancing the screw pushes the blade down (flat) over the wires, but there is still an edge in contact with the wire.
If you can minimize wire movement, you'll probably be fine with a terminal strip regardless of the gauge. To me this was a point of failure.
Besides, I had the components already from previously building 10Base-T cables (remember when you had to do that?), so this was an easy solution for me.
posted 03-14-2011 07:06 PM ET (US)
I would tend to not use the screw compression binding terminals on the basis that they came from Radio Shack. As a general rule I tend to outlaw anything purchased at Radio Shack from being used in anything I construct.
posted 03-14-2011 07:26 PM ET (US)
Jim, your point is noted. In the six years I've used these terminal strips on my Whaler and 70 other install I've never had any connectivity issues or wire failure. All my installs on boats that operate exclusively in the saltwater in all sorts of conditions.
posted 03-14-2011 09:26 PM ET (US)
Tom, I don't doubt you at all.
I've got a couple of the the little Raymarine junction boxes on my boat (they're just gussied up versions of a terminal strip in a plastic box with a Raymarine logo, they look nice though).
For larger gauge wires they work great; they're easy and durable.
For small wires, not so much.
posted 03-14-2011 09:38 PM ET (US)
Tom--Those screw-down compression connecting posts from Radio Shack probably work for you because:
--you know how much torque to apply when tightening them
--you keep the wires under them from having any tension or movement
--you use them in places were it is reasonably easy to reach in with a screwdriver and tighten or loosen them
--you use them in places where they are protected from water
I think there are better ones of that type, and in this case I mean better because of the way the wire is pinched under the connector. The ones I like use a flexible silver or nickel plated shim between the screw and the wire, and as the screw is tightened the shim comes down and pinches the wire. The rotating screw never hits the wire.
posted 03-15-2011 06:23 AM ET (US)
I followed Tom's advice and go the screw down terminal block except I paid 3x as much for the Ancor version of the shack blocks. Not sure if they are any better just I got them before I knew about them at Radio Shack.
Installed them in December, we will see how well they hold up. I did tin the wires before screwing them down.
posted 03-16-2011 11:59 PM ET (US)
Rob--Nice pictures. Also, I like that sexy right-angle UHF series adaptor on the radio antenna connection.
posted 03-17-2011 05:59 AM ET (US)
Thanks Jim. That 90 degree fitting is the only way the radio would fit in there. I even had to make a shim plate for the face out of 1/4" starboard. You can kind of see it in this picture.
By the way, I could not find a good local source for the small NMEA 0183 wires that go from the radio to the GPS (the reason for the blocks) I ended up using an extra section of Cat 5 computer cable. Yes, I know that it is not tinned but at least it is stranded wire. I did tin the ends and used heat shrink where the wires go into the sheath. We will see how it hold up. Any good sources of small gauge multi colored marine wires?
posted 03-17-2011 07:02 AM ET (US)
"Radio Shack, you've got questions, we've got blank stares"
posted 03-17-2011 09:30 AM ET (US)
Good wire has become rather expensive lately. I get most of mine out of a box of scrap wire that I have been collecting for the last 45 years. The last time I bought new wire specifically for marine use I purchased from an on-line seller whose prices were attractive: Genuinedealz.com. I'd check their website to see what they have for small signal wire.
When you buy small reels of multi-conductor cable you really pay a premium for it. BELDEN makes good wire and has very wide distribution. Big mail-order places like DIGI-KEY sell some off-brand wire and cable at OK prices. ALPHA makes great wire and cable, but their prices reflect the premium quality. For marine use a wire should be stranded and tinned. In marine specifications the minimum wire gauge is supposed to be 16-AWG which is too big for signal wire. Smaller 18-AWG wire can be used if it is bundled with other conductors.
A good 18-AWG wire for marine use is made with 19-strands of 30-AWG wire. This makes for a very flexible wire. Less expensive 18-AWG wire has fewer strands. For marine use the insulation on the wire should be water, oil, and fire resistant, although I would not worry too much about that for a small signal wire. If a wire carrying a small signal like NMEA-0183 serial data is exposed to water, oil, and fire you likely have bigger problems to worry about than the integrity of that wire.
Here is a pointer to 18-AWG marine grade wire sold by Genuinedealz:
Genuinedealz may have more colors available than they show on their website. I would check with them via telephone or email.
Here is a pointer to a Belden catalogue where you can find many multi-conductor cables:
Here is a pointer to DIGI-KEY's catalogue search for wire:
Their CAROL-brand wire is less expensive.
posted 03-23-2011 09:51 PM ET (US)
For marine connectors:
posted 04-04-2011 06:24 PM ET (US)
Thanks all for the excellent suggestions. I ended up doing pretty much what David Pendleton did. I soldered stranded conductor phone wire (possibly 28 AWG) to the pigtails and terminated them with RJ11 plugs. They are then joined with a double-female connector from the dreaded Radio Shack. If the supplied wires weren't so very fine, life would be easier.
posted 04-04-2011 06:35 PM ET (US)
I think this is why people don't enable the GPS function on their DSC equipped radios. A few years ago, I tried to connect wires individually, but without a successful outcome.
Perhaps this spring, I will attempt it again using the ideas mentioned here.
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.