Joining thin wires

[Ru88ell]

I'm going to relocate the nest of wires from my cockpit and chart table instruments to a better place, but some are going to need to be extended. I'm talking thin NMEA stuff. What's the best way to joint them? Solder? Connectors?

 

[GHA]

With some heatshrink ontop.

If you do then send a few pics so we can nitpick

 

[Gwylan]

We used WAGO connectors. They are excellent, you can change your configuration and add remove items. The connectors can be packed into one of their boxes or you can use almost any container for the connector blocks.

Buy a selection of 2,3 & 5 way blocks.

 

[elton]

Solder and heatshrink.

 

[Bru]

Wago good, solder bad!

 

[eddystone]

3M/Scotchlock gel filled are good for that purpose - I found some on ebay.

 

[Hydrozoan]

I've used one of these push button terminal blocks http://uk.rs-online.com/web/p/non-fu...locks/0815852/ by Wago, which has tin-plated copper contacts and goes down to 28AWG. It was very easy to use and also comes in a smaller size (6 or 8 way?) I think.

 

[Ian_D]

Wago good, solder bad!

How can solder be bad? I don't see how anything can be better than a proper soldered & heatshrink joint?

The only exception to this is on RF cables / HF data cables - which would need proper joiners - Coax for example, shouldn't be joined by anything other than a specific coax connector designed for it, otherwise the impedance & shielding will be wrong, degrading the signal at least.

 

[Aurai]

This link

Offers a short list of pros and cons to both approaches

http://www.controlgrips.com/pdf/crimp_or_solder.pdf

I have a additional sense that soldered joints on boats are discouraged as they add a level of brittleness into an harsh environment, vibration? Not sure from my own experience that any joints fail whether crimped and then soldered or not and try to double check every joint is "well made". Heat shrink provides mechanical support and is a key part of my approach.

 

[Spuddy]

Bit puzzled by "solder bad " convention. After all, the pcbs on the kit have soldered bits so equally prone to vibration problems. Furthermore most boats travel very little compared to other vehicles: planes, trucks etc so engine vibration at least is not long-lasting.
I do solder and heatshrink but I'll have a look at these Wago connectors

 

[lw395]

Soldered connections shouldn't have any mechanical stress on them.
Particularly in small sizes.
It's important to anchor both sides of the join with cable ties, lacing cord or whatever.

That's also true of most connector systems.
Most the unreliability seems to be down to this sort of issue rather than the choice of actual joint.

Heat shrink is a good start to strain relief, but it still needs decent support.

 

[ShinyShoe]

Like all these things you find people who have great success with things others tell you will cause the moon to crash into the sun.

There are a fair few boats out there with wires twisted together and insulating taped. Done to get a fault fixed, done to find the right wiring for NMEA only to never get round to fixing properly because it never failed.

The concern with solder is not the electrical quality of the join. That is as good as anything possible with any join. It's that you create an inflexible section on the wire. During stripping you may damage the wire and during soldering may also damage. A vibration on the wire, or motion from the sea, repeatedly causes the flex wire to move and the join stays still. Result over time the wire may break. It can be overcome at least in part with heatshrink plus glue. That moves the load to somewhere where the insulation is intact and it may flex a bit too. Add to that securing the wires to a surface either side of the join and you can probably mitigate the risk of strain on the join.

But worth looking at gel filled crimps like BT etc use. No stripping wire, water resistant. Cheap. No burned fingers (thin wire heats lots with solder)

On the why don't PCBs fail... No strain on the components. Most wires feeding a PCB feed via a block not solder. Block takes strain of movement.

 

[Hydrozoan]

... I do solder and heatshrink but I'll have a look at these Wago connectors

Regarding Wago and similar connectors, which type you would go for obviously depends on the disposition of the wiring. I was looking at the small levered ones Gwylan refers to (I think), but as all my instrument wiring came to one dry location I found the 12 way block excellent - and the push fit system very convenient in a situation with limited room to manoeuvre (oneself and tools). Whatever connection methods you are considering, access is worth a careful thought.

 

[coliholic]

IIRC aviation specifically bans soldered joints due to vibration problems

 

[lw395]

IIRC aviation specifically bans soldered joints due to vibration problems

Not entirely true.
Aviation does not have simple rules like 'no soldered joints', aviation has standards and recommendations running to hundreds of pages.
Aviation is not a big user of twisted wires and sellotape, or crimps from Halfords either.
AIUI, there are detailed rules about solder not being the sole means of support of a wire, strain relief is a big thing.
The military were very slow to adopt lead free solder though, as it can be more brittle.

 

[elton]

I'm still using phono and DIN audio leads from the 1960s, still in use, all soldered connections, and none have ever failed.

Failures are almost always due to poor soldering technique in the first place, or repeated flexing, which would just as likely cause any wire to fracture.

And as already mentioned, every bit of electronics on a boat is loaded with soldered connections.

I'd guess those arguing against soldered joints have simply never mastered the skill. A bad joint is just as easy to make as a good one.

 

[Bru]

I'd guess those arguing against soldered joints have simply never mastered the skill.

Bad guess. Wrong!

(As an apprentice in the lift industry, learning to solder properly was a key skill to the extent that if you couldn't you wouldn't get out of first year training)

But in a way you are right - not many people have the skill or equipment to solder properly to professional standard (and it isn't helped by lead free solder which is the work of the devil as far as I'm concerned. Have to use the stuff for legal reasons but oh how I long for proper solder)

Soldering two wires together and sticking heat shrink over the joint is, and always has been, a bodge frankly. With the range of crimp connectors and terminal blocks now available there's better ways of doing it which is why I stick by "solder bad" when it comes to jointing wires - and especially stranded cable where soldering invariably produces a potential stress fracture zone

 

[davidpbo]

It is virtually impossible to say one method of connection good another bad, particularly for thin low voltage signal cables. It depends on so many factors including location, access, tools, skill etc.

For me I would have no problem using solder especially on my own boat, it is not always possible to adequately mount a suitable connector or block that accepts very small cables. Leafed connector blocks are needed IMHO which are not readily available and bootlace ferrules (with crimper).

If the cable is screened then it is difficult to maintain the integrety of the screen using connector blocks.

If you can get appropriate in line connectors that is an option but may well involve soldering to pins and some can be a b*****d to solder particularly in a panel.

If soldering, I would stagger the core joints, twist the wires together in line for maybe 10mm insulate each core with either heatshrink or rubber sleeves. If the cable is foil screened with a drain wire I would solder the drain wire (in line) wrap some foil tightly over the whole joint and heatshrink over the whole joint.

Done properly in a suitable location and against vibration and stress it can be a solution to the problem of joining cables.

I am sure it is not up to aviation spec. I see a few planes which float but few boats that fly.

 

[elton]

Bad guess. Wrong!

(As an apprentice in the lift industry, learning to solder properly was a key skill to the extent that if you couldn't you wouldn't get out of first year training)

But in a way you are right - not many people have the skill or equipment to solder properly to professional standard (and it isn't helped by lead free solder which is the work of the devil as far as I'm concerned. Have to use the stuff for legal reasons but oh how I long for proper solder)

Soldering two wires together and sticking heat shrink over the joint is, and always has been, a bodge frankly. With the range of crimp connectors and terminal blocks now available there's better ways of doing it which is why I stick by "solder bad" when it comes to jointing wires - and especially stranded cable where soldering invariably produces a potential stress fracture zone

I've just asked my lecturer on the C&G Level 2 Electrical Installations course, and he says soldered and crimped unions are both classed the same in terms of quality for permanent unions, and both depend upon correct technique as well as appropriate tools and materials. He also happens to be a boat owner. He tells me he solders with lead/tin resin cored, and insulates with heat shrink. So that's good enough for me.

 

[Bru]

Well firstly he's clearly not up to date on current standards in the marine industry

In fact, he's not even up to date with standards in the lift industry more than thirty years ago! From soldering everything in sight we changed to using crimp connectors instead virtually overnight due to the significant production and reliability benefits

And he also appears to be blissfully unaware that it is now illegal (with esoteric exceptions which do not apply in this context) to use leaded solder commercially

(You can purchase and use leaded solder on your boat, I can too on my boat. But I cannot use leaded solder on your boat, it is and has been for some years, illegal to do so. Leaded solder hasn't been used in commercial production applications for yonks, for that matter)