Non rust chocolate blocks

[john_morris_uk]

I will not comment, I will not comment, I will not comment... Oh buggar it, yes I will. You get a hard point where the crimp stops and the wire starts too. If you solder properly you'll end up with the stress point properly supported by the heat shrink collar.

Hmm - I used to think the same and use the same logic and use exactly the same solder fittings!

Until someone pointed out that aircraft always use crimps as soldering has proved unreliable for the reasons I outlined. So I changed my mind and started using best quality marine crimp connections with a proper crimping tool.

Its 'possible' for crimping to produce a hard point - but much less likely when the crimp is done properly. Solder 'nearly always' produces a hard point as the solder wicks up the wire, and in some cables it can wick up several mm. If it doesn't wick up the wire, then there will still be a hard point at the connector which needs support.

In reality I still use those solder joints occasionally and for some applications, but I make sure that the heat shrink or tape supports the cable so that the hard join interface isn't stressed by vibration or movement. For example all my battery cables are soldered into large lugs which go onto battery clamps. The cable/lug intersection then gets wrapped in electricians or amalgamating tape etc.

 

[lw395]

Hmm - I used to think the same and use the same logic and use exactly the same solder fittings!

Until someone pointed out that aircraft always use crimps as soldering has proved unreliable for the reasons I outlined. So I changed my mind and started using best quality marine crimp connections with a proper crimping tool.

.......

Unfortunately, that's an urban myth.
There are lots of soldered wire connectors used in aircraft.
Both civil and military.
I've seen plenty of the solder cup variety of these:
http://www.amphenolcanada.com/ProductSearch/pdf/485_BRO.pdf

 

[David2452]

Thing is though, those are used by people who can solder properly and who do it all day every day, something that most people can not do, I have been using crimps for so long, even on very small terminals like Deutch .5mm2 barrels that I have probably lost the ability to make a really good joint myself. Also those type of connections almost always have close adjacent strain relief.

 

[KellysEye]

We used one choc box because our Jabsco water pump motor comes with wire pigtails. Since the motors are known to blow (happened twice) a choc box is the easiest way to connect wires. We used to cover it with electrical tape which is easy to get off rather than self almagamating tape.

 

[PITCAIRN]

Loads of great info on electrical systems, wiring, connectors. Includes a useful wiring size calculator.

http://www.ezacdc.com/boat-wiring-products/wire-and-cable/tinned-boat-wiring/

 

[lw395]

Thing is though, those are used by people who can solder properly and who do it all day every day, something that most people can not do, I have been using crimps for so long, even on very small terminals like Deutch .5mm2 barrels that I have probably lost the ability to make a really good joint myself. Also those type of connections almost always have close adjacent strain relief.

Good soldering and good crimping are both fine.
Trying to solder using a cheap 12V iron is sometimes as bad as using the wrong crimp tool.
Bad crimping is a menace.
At least with choc-blocks you know it's a good place to start looking for a fault!

Proper strain relief and securing cables into looms etc are what makes wiring reliable, as well as not having any joints where they will get wet.

 

[David2452]

Good soldering and good crimping are both fine.
Trying to solder using a cheap 12V iron is sometimes as bad as using the wrong crimp tool.
Bad crimping is a menace.
At least with choc-blocks you know it's a good place to start looking for a fault!

Proper strain relief and securing cables into looms etc are what makes wiring reliable, as well as not having any joints where they will get wet.

Absolutely no argument with any of that.

 

[john_morris_uk]

Unfortunately, that's an urban myth.
There are lots of soldered wire connectors used in aircraft.
Both civil and military.
I've seen plenty of the solder cup variety of these:
http://www.amphenolcanada.com/ProductSearch/pdf/485_BRO.pdf

Well I don't know who to believe now as it was someone on these forums who claimed to be an aircraft mechanic who waxed long and lyrically on how he wasn't allowed to solder connections on an aircraft and it would fail its certification if any were found.

I was an electronics engineer once and don't think I've completely lost my skills at soldering, so (as I mentioned before) I still solder some connections on the boat but mostly I crimp them...

 

[lw395]

Well I don't know who to believe now ....

It's not about belief, it's about knowing it's been done well enough to work.
Whatever methods have been used, if it's been done Ok, it is OK.
The fact that the wiring on my heads light would not be acceptable on the space shuttle really does not matter. So long as the light always works.

If you are specifying how you want your new Oyster wired, that's a different question.

 

[john_morris_uk]

It's not about belief, it's about knowing it's been done well enough to work.
Whatever methods have been used, if it's been done Ok, it is OK.
The fact that the wiring on my heads light would not be acceptable on the space shuttle really does not matter. So long as the light always works.

If you are specifying how you want your new Oyster wired, that's a different question.

Let me rephrase that.

I don't know whose opinion to believe as to what is best practice.

I agree that you can say, 'so long as it works, then its ok.' But twisting the wires together will work for while. I try to wire things so that they are reliable over the lifetime of the device which is why I am interested in best practice and therefore who to believe about soldering or crimping connections. What they do on aircraft is pertinent to the question.

 

[Graham_Wright]

Well I don't know who to believe now as it was someone on these forums who claimed to be an aircraft mechanic who waxed long and lyrically on how he wasn't allowed to solder connections on an aircraft and it would fail its certification if any were found.

I was an electronics engineer once and don't think I've completely lost my skills at soldering, so (as I mentioned before) I still solder some connections on the boat but mostly I crimp them...

I used to work for an aerospace company and there were thousands of soldered joints in the equipment we produced.

However, the cables were very tightly bound, secured and, usually, coated with an overall goo.

I use crimps on the boat but, having suffered with oxidised wiring in the past, wonder what happens within the crimp. At least with a soldered joint you know the solder is unlikely to detach from the conductor.

 

[tudorsailor]

As I have no practical electrical training (apart from nerve surgery) can I ask a naive question?

If I want to have two lights coming from a single 24v supplying cable, what is the best way to connect. The situation is not exposed to the wet, but may be damp as it is within the boom. I was going to connect with a chocolate block but having read this thread I am not so sure

Thanks

TudorSailor

 

[lw395]

As I have no practical electrical training (apart from nerve surgery) can I ask a naive question?

If I want to have two lights coming from a single 24v supplying cable, what is the best way to connect. The situation is not exposed to the wet, but may be damp as it is within the boom. I was going to connect with a chocolate block but having read this thread I am not so sure

Thanks

TudorSailor

Whatever you use it needs to be protected from water and abrasion from ropes.
Choc blocks sealed with self amalgamating tape, soldered connections covered in adhesive lined heatshrink, waterproof connectors, crimp terminals inside a waterproof junction box?
Any of it can fail, you have to balance the effort vs the consequences of failure.

The most reliable way might be to run individual wires back to inside the yacht IMHO.

 

[grumpy_o_g]

I think, as most above have said the answer (which may not be any use at all) is whatever joint you can make the best. If you can solder then good, if you can crimp (not quite as straightforward as it may seem sometimes) then good. Either method is simply making the connection though. lw395 summed it up well:

"Good soldering and good crimping are both fine.
Trying to solder using a cheap 12V iron is sometimes as bad as using the wrong crimp tool.
Bad crimping is a menace.
At least with choc-blocks you know it's a good place to start looking for a fault!

Proper strain relief and securing cables into looms etc are what makes wiring reliable, as well as not having any joints where they will get wet.

Choc blocks and twisted wires aren't recommended but they'll last a remarkably long time if you support and protect them properly."

For something in a boom I'd first make absolutely sure the cables are dry and have been for a while (otherwise you're just going to trap any moisture that's already wicked up into the cable when you seal the joint. If you're not comfy soldering then crimp it by all means.

Get yourself some self-adhesive heat-shrink butt crimps such as these and the right ratchet crimping tool to crimp (don't get a cheap tool as you won't get a decent crimp usually).

Strip and clean the cables carefully, making sure you don't nick the conductor when you strip the insulation and making sure you take off the right length. Try and avoid touching the conductor after you've stripped it. To strip the insulator roll the insulator very carefully against a Stanley knife blade (trying not to go all the way through to the conductor) then get hold the insulator at the end of the cable and twist it off. Do it right and you will twist the filaments of the conductor as as you rotate the the little piece of insulator you remove, leaving the conductor twisted but without you touching it. Either that or use automatic wore strippers such as these. Edit: if you've done nerve surgery then you you should manage the first method of stripping.. - I use Swann Morton scalpels in fact.

Once you've crimped the joint and heat-shrunk it cover it in Sikaflex or similar taking care not to leave air bubbles (you only need a 1/8" or so around it) and then wrap self fusing tape around the whole thing tapering the joint as much as possible at each end (this is to to support the cables as much as any kind of waterproofing),

 

[alahol2]

The situation is not exposed to the wet, but may be damp as it is within the boom. I was going to connect with a chocolate block but having read this thread I am not so sure

I would have thought the connection is the least of the problems. My question would be how do I get it out of the boom and into the boat without the cable work hardening and breaking because of the movement of the boom?

 

[tudorsailor]

I would have thought the connection is the least of the problems. My question would be how do I get it out of the boom and into the boat without the cable work hardening and breaking because of the movement of the boom?

At the forward end I have easy access to a waterproof connector. The live end has power. The wire then disappears inside and along the boom. There are two halogen downlights above the cockpit each with a separate hole for the bulb (I have a centre cockpit). I am assuming that I can pull the existing connection out through one of the holes and make the new connections before sending it back inside. I am hoping not to replace the whole cable running in the boom. Then I will be asking if there is a special outdoor cable that I should use............

Thanks

TudorSailor

 

[alahol2]

Maybe the thing to do is to attach a dri-plug socket at the end of the boom then use a flylead with a dri-plug plug on the end to make the connection only when required.

 

[TNLI]

Look why not just give em a light spray with WD60 or 40.

Peter

Not a good idea as it's too light and might cause the tiny screws to unwind.

PCB spray works, similar to contact cleaner, BUT it has a varnish dissolved in the Isoprop alcohol that does not evaporate. It forms a protective layer that will stop corrosion far better than a light oil. Some greases are far better for heavier threads, if you can't afford Duralac.

 

[TNLI]

I agree - they are available, but properly crimped connectors are better.

The ones I have used (when pushed) have had the tang inside. They are stainless - or plated brass and don't corrode.

Better option would be crimped with the special marine connectors that have heatshrink stuff on them that seals onto the insulation of the wire where it enters the crimp connector? (Do the crimp and then heat with a hot air gun etc to shrink the seal onto the wire.)

If you haven't got a proper crimping tool, you might get away with soldering and heat shrink over the top? The problem is that you get a 'hard' point where the solder stops and the wire starts and the wire can eventually fracture at this point. Hopefully the heat shrink supplies enough support, but its not the optimal solution.

If you get salt water into a Copper wire or fitting that has solder on it, then you will have made a battery! Net result is the dreaded electrolysis. I do solder some wires that are well above bilge water or salt spray areas, BUT I use top of the range micro sealant over the joint, first class electrical tape and finally shrink wrap over the whole area or wire terminal. In an emergency I use stainless temporary fittings, like West Marines chocolate blocks. Tough to find due to stupid non stainless copies or recycled stainless use in the far East.

 

[RichardS]

The thread is rather zombified so I'm not going to bother reading it again .... but it seems that the simple answer is to do what I do and buy choc block type connectors with stainless steel contacts.

Richard