Simple electronic install - first time advice needed

Don S/V ILLusion · Apr 5, 2024

Most reliable way to ‘splice’ fine wire sizes is terminal block connections. Alternatively, they can be soldered but need a solid mechanical connection anyway so just do #1. Fusing is textbook practice method you can read on your own.

elink · Apr 5, 2024

I am no expert but I do have both an electrical and electronic background.
1. Soldering and then heat shrinking is the best way to connect fine wires. Heat shrink with integral mastic will coat the connection as well.
2. As long as the load of the two devices are within the current rating of the switch, they could share the one switch. I would still recommend a fuse inline to protect the equipment and wiring, should there be a short circuit. As the load between the VHF and the AIS device are likely different ratings, a separate properly sized fuse should be used for each.
3. For either switch, new or existing, the switch should be inline with the + wire of your attached drawing
3 again. You need to size your wiring to the size of the applied load. Then use an applicable fuse or circuit breaker. The idea is to protect the wire from being damaged by overheating if the load is higher than the wire is rated for. For example you can use a 10 amp switch with 15 amp wire to supply a 1 amp load (such as a small electronic device). To protect the electronic device a fuse in this case would be between 1.1 to 1.5 amps. This allows the device to draw full load without blowing the fuse (or damaging the wire or switch) during normal operation but will blow if the circuit draws more than the full load rating of the device. For wire sizing, you could reduce the size of the wire to suit the 1.1 through 1.5 amp rating of the fuse (applying a 1.1 to 1.5 multiplier to whatever load rating is needed, and this multiplier could be higher for inductive loads like motors, transformers, or heaters, etc.) as this would be the most the circuit would ever see, however this is not practical typically in these low current situations. Often one has a roll of wire suitable on hand for repairs (ie: 14 AWG, 16 AWG, or 18AWG) and as long as the fuse rating is lower than the current rating of the wire, you are safe. As good practice, you would use 10 amp wire on a 10 amp switch but this is not necessary as long as fusing is correct.
4. It is typically recognized that - is equal to a ground connection on most 12VDC systems. This is not 100% of the time but very close to it. I have heard of boats using + as the ground connection but I haven't run into it myself.
PS. Typically this is done with a fusible link. These are designed to melt at designed current levels. They vary widely in appearance. A Google search of fusible links will provide you with some examples

dlochner · Apr 5, 2024

circa1971la said:
1. What’s the best way to splice the very fine NMEA 0183 interfacing wires coming from the new device to my VHF?

Ring terminals and a terminal block. Soldering on a boat is generally frowned upon because it forms a hard spot where the wires can break at the edge of the soldered connection. Wiring on a boat needs to be flexible because of the movement and vibration on the boat.

circa1971la said:
2. The manual says I can use an inline fuse or a switch for the device. I’d prefer a switch so there’s not constant draw. However, theres no excess ones on my Sea Dog panel. If I don’t exceed the capacity of the switch can I have the new device share the same switch as my VHF for example? Or do I just upgrade the capacity of the switch so they can share it ?

Are you using a switch or a circuit breaker? The wire needs to be protected so it needs a fuse or a circuit breaker. If you have an appropriately sized fuse you can use a simple rocker switch, if no fuse, then a circuit breaker is necessary.

circa1971la said:
3. Regarding choosing the proper wire size for the load, I will use the ABYC guide from https://boathowto.com/electrics/wire-size-calculators/ . However, I’m not clear on what is meant by “If there is already an existing fuse or circuit breaker for the conductor you are planning to replace, you can enter the amperage of the fuse/circuit breaker in the calculator instead of the amp rating of the consumer.” Does this mean if I’m using a device that draws 8 amp but the switch is rated for 10 then I use 10 in the calculation on the wire ?

Fuses and circuit breakers protect the wire from overheating and potentially catching fire. The size depends on the smallest wire down stream from the fuse/breaker. It is also necessary to calculate the current loss due to the wire size. It is best to keep the voltage loss to 3% or less. That loss is base on the amount of current (amps) drawn, the size of the wire, and the length of the wire run. In DC systems wire runs are always a round trip, i.e., the combined length of the DC+ and DC- wires. In terms of fuse size, the actual draw is less important than the max current the wire can support.

circa1971la said:
4. I’m confused why the wiring diagram shows no path to ground. It just shows the red wire to + and the black to -

There are only 2 wires in a DC circuit, DC+ and DC-. Referring to the DC- as ground is an archaic term because it is easily confused with AC grounds which are an entirely different thing.

In automobiles the DC- may be referred to as ground because the car's frame and body are used as a route for the DC- back to the battery.

Calder's writing can be a little dense and difficult to understand for the beginner as it tends to be very technical. Charlie Wing's book, Boatowners Illustrated Electrical Handbook (Amazon Link) is easier to understand.

dLj · Apr 5, 2024

dlochner said:
Ring terminals and a terminal block. Soldering on a boat is generally frowned upon because it forms a hard spot where the wires can break at the edge of the soldered connection. Wiring on a boat needs to be flexible because of the movement and vibration on the boat.

While the above is true, soldering is still an acceptable method of joining wires on a boat. The hard spot can be avoided through the use of support systems. On thin wires in a butt connection using marine grade heat shrink that extends well beyond the soldered connection, and then a second heat shrink on top of that that also extends beyond the soldered connection but not as far as the first heat shrink. That stabilizes the solder connection and relieves the flexing at the wire to solder joint.

dj

mermike · Apr 5, 2024

A terminal block is best. Heat shink. adhesive lined butt splices and ring terminals in small diameters are available here and here.

Per ABYC:
11.14.3.7 Solder shall not be the sole means of mechanical connection in any circuit. If soldered, the connection shall be
so located or supported as to minimize flexing of the conductor where the solder changes the flexible conductor into a
solid conductor.
EXCEPTION: Battery lugs with a solder contact length of not less than 1.5 times the diameter of the conductor.
NOTE: When a stranded conductor is soldered, the soldered portion of the conductor becomes a solid strand
conductor, and flexing can cause the conductor to break at the end of the solder joint unless adequate additional
support is provided.

I think for the OP's needs a decent crimper would be more useful and less of a PITA than a soldering iron.

dLj · Apr 5, 2024

mermike said:
A terminal block is best. Heat shink. adhesive lined butt splices and ring terminals in small diameters are available here and here.

Per ABYC:
11.14.3.7 Solder shall not be the sole means of mechanical connection in any circuit. If soldered, the connection shall be
so located or supported as to minimize flexing of the conductor where the solder changes the flexible conductor into a
solid conductor.
EXCEPTION: Battery lugs with a solder contact length of not less than 1.5 times the diameter of the conductor.
NOTE: When a stranded conductor is soldered, the soldered portion of the conductor becomes a solid strand
conductor, and flexing can cause the conductor to break at the end of the solder joint unless adequate additional
support is provided.

I think for the OP's needs a decent crimper would be more useful and less of a PITA than a soldering iron.

If you look at your links - those butt connectors stop at 22 gage. Wiring used for NEMA 0183 is typically 28 gage - I have yet to find adhesive butt connectors for that fine gage wire. But I can find adhesive heat shrink that will work down to that gage wire. And as you have stated per ABYC solder connections are permitted to be used but need to have a secondary means of mechanical support - which is what I described.

Read his point 1 - if he is doing butt connections with 28 gage wire - I'd sure like to know both where you are getting both the butt connectors and the crimp tool to make that joint. It would be better to solder those wires or possibly use a terminal block. But I think a soldered butt joint would be an excellent way to make that joint.

circa1971la said:
I will be doing my first electronics install. I’ve chosen a “simple” project but need some advice free if sarcasm etc..I’ve read and watched what I can from Nigel Calder and I’m installing a device that sends AIS data from my VHF to Navionics app: see image below

Questions:
1. What’s the best way to splice the very fine NMEA 0183 interfacing wires coming from the new device to my VHF?

dj

mermike · Apr 5, 2024

dLj said:
If you look at your links - those butt connectors stop at 22 gage. Wiring used for NEMA 0183 is typically 28 gage - I have yet to find adhesive butt connectors for that fine gage wire. But I can find adhesive heat shrink that will work down to that gage wire. And as you have stated per ABYC solder connections are permitted to be used but need to have a secondary means of mechanical support - which is what I described.

Read his point 1 - if he is doing butt connections with 28 gage wire - I'd sure like to know both where you are getting both the butt connectors and the crimp tool to make that joint. It would be better to solder those wires or possibly use a terminal block. But I think a soldered butt joint would be an excellent way to make that joint.

dj

I inadvertantly edited out part of my post. I was going to suggest that he strip the wires twice the length, fold the stripped length in half, and crimp.

Also, the ring terminals go as small as 26-24 AWG. I modified a pair of pliers to make tiny crimps.

dLj · Apr 5, 2024

mermike said:
I inadvertantly edited out part of my post. I was going to suggest that he strip the wires twice the length, fold the stripped length in half, and crimp.

I definitely feel a solder joint is a better option. I did exactly that on two small wire joints on my boat and both broke within two months. The solder joint I described has now lasted over 10,000 nm.

dj

marcham · Apr 5, 2024

There's a reason boat builders and Nasa don't solder any wire joints... although not sealed, mechanical joints don't weaken the wire and do better in a high vibration environment.

201 CRIMPED TERMINATIONS GENERAL REQUIREMENTS

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dLj · Apr 5, 2024

marcham said:
There's a reason boat builders and Nasa don't solder any wire joints... although not sealed, mechanical joints don't weaken the wire and do better in a high vibration environment.

201 CRIMPED TERMINATIONS GENERAL REQUIREMENTS
.

You seem to be missing a major concern here - in the marine environment - I cannot find crimp connectors for 28 gage or smaller wire with an adhesive liner, which is what you need in the marine environment. I also don't know where you find crimpers for making those fine wire joints. I'm not discussing the advantages or disadvantages of crimped versus soldered. Crimped are the best option.

But doubling over wire so you can fit an inappropriate sized connector is not the answer. And if you can't find either the connectors nor the tool to make a correctly made crimp connection - soldering and making sure you provide the mechanical support needed is a good connection.

Now, if you can please provide me with where to by marine grade connectors for 28 gage and below along with the proper crimp tool, I'll buy them in a heartbeat.

From your reference:

"Crimping is an efficient and highly reliable method to assemble and terminate conductors, and typically provides a stronger, more reliable termination method than that achieved by soldering."

Notice where it says "typically provides"... A properly done solder connection can be just as reliable. But it takes more work, and more insight into what makes them reliable.

dj

elink · Apr 6, 2024

While the discussion continues on this, circa1971la, you can likely make a decision on what is best for you. Good recommendations and precautions have been provided by the contributors above. I too suggested solder because butt splicing small wiring is problematic because of the lack of supply at this wire gauge and the fragile nature of the wires. A terminal block is a good method of connection but not always practical depending on availability of enough surface to mount to near where the connections are required. In all cases, wiring should be supported, even with a terminal block.

mermike · Apr 6, 2024

Just don't ask which anchor is best...

dLj · Apr 6, 2024

circa1971la said:
Thank you all so many wonderful suggestions. It seems of all of these, the best option is to use the terminal block. I’m only dealing with two small wires for this device next to my VHF.

@circa1971la A terminal block is a good way to go - just don't forget the mechanical support for the wire.

In your first post, you asked for "advice free of sarcasm" - How did we do?

dj

dlochner · Apr 6, 2024

mermike said:
Just don't ask which anchor is best...

Oh, come on, that's too easy. Its the one hanging on my bow roller.

Simple electronic install - first time advice needed

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