Bootlace Crimp into Automative Crimp?

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MikeAqua

6058 posts

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#275885 15-Sep-2020 10:21

Can I crimp a bootlace onto a fine wire and then crimp an automotive terminal onto the bootlace?

Background
I have some very, fine (>AWG-24) wires (NMEA-0183 leads) that I need to terminate on my boat. This lead carries the position data from the plotter to the VHF

As this is a marine application, I'm using adhesive heat shrink terminals , overlaid with adhesive heat shrink tube, onto a ring-screw terminal block.

The terminals I'm using, don't crimp down tight enough for the very fine wires the manufacturer provides (please note the spec for the terminals seems to be in wire diameter, not mm2).

Mike

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1566 posts

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#2564256 15-Sep-2020 10:53

I'm not a marine electrician, but I'm pretty sure that bootlaces won't conduct electricity. I'd suggest using wire.

wellygary

4999 posts

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#2564257 15-Sep-2020 10:57

BlueShift:

I'm not a marine electrician, but I'm pretty sure that bootlaces won't conduct electricity. I'd suggest using wire.

A bootlace crimp is steel, its called that because it looks like a what's on a bootlace, its not the same.. :)

elpenguino

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#2564273 15-Sep-2020 11:22

Should be ok with appropriate support and strain relief.

Consider a permanent/direct connection which you'll be able to waterproof for better corrosion resistance. Unless you want to have terminals available for future expansion, of course.

MikeAqua

6058 posts

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#2564346 15-Sep-2020 13:50

elpenguino:

Should be ok with appropriate support and strain relief.

Consider a permanent/direct connection which you'll be able to waterproof for better corrosion resistance. Unless you want to have terminals available for future expansion, of course.

Thanks. The adhesive heat shrink provides some strain relief. The wires are cable tied in a drip loop which is secured to a cable tie block on the bulkhead, below the junction block. I'm copying what I see professional marine auto-sparkies in the US doing. They all seem to use junction blocks for device wiring. Fast easy and tidy.

I'm interested to know what you mean by a permanent connection?

In this case I'm joining one proprietary lead (Uniden) to another (Lowrance), so some sort of join/junction is unavoidable.

Power leads for boat components are usually quite short, so again a join of some sort is unavoidable. For example, the power leads on my LED navigation lights were only 150mm long. There is trend for short leads, made from lightweight wire in marine components. It's penny pinching and a PITA.

Mike

elpenguino

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#2564443 15-Sep-2020 15:25

MikeAqua:

I'm interested to know what you mean by a permanent connection?

In this case I'm joining one proprietary lead (Uniden) to another (Lowrance), so some sort of join/junction is unavoidable.

Power leads for boat components are usually quite short, so again a join of some sort is unavoidable. For example, the power leads on my LED navigation lights were only 150mm long. There is trend for short leads, made from lightweight wire in marine components. It's penny pinching and a PITA.

Permanent connection, meaning soldered or crimped wires with multiple layers of progressively longer heatshrink and waterproofing tape.

The plating on the terminals didn't look amazing quality so, assuming you're not using an enclosed vessel, I would put the whole connection shooting match in a good quality waterproof enclosure with appropriate cable glands.

MikeAqua

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#2564457 15-Sep-2020 15:47

elpenguino:

Permanent connection, meaning soldered or crimped wires with multiple layers of progressively longer heatshrink and waterproofing tape.

The plating on the terminals didn't look amazing quality so, assuming you're not using an enclosed vessel, I would put the whole connection shooting match in a good quality waterproof enclosure with appropriate cable glands.

Solder is generally a no-no in boats these days. The ABYC advise against it.

The terminals are crimp + adhesive heat shrink and I do an additional layer of heat shrink over top.

The terminal blocks are behind a dashboard so they won't get splashed or anything. BEP make good gear, it's all tinned copper. I have BEP busbar in a more exposed location that's been there for about 16 years and it has just started corroding

Mike

elpenguino

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#2564480 15-Sep-2020 16:27

MikeAqua:

Solder is generally a no-no in boats these days. The ABYC advise against it.

The terminals are crimp + adhesive heat shrink and I do an additional layer of heat shrink over top.

The terminal blocks are behind a dashboard so they won't get splashed or anything. BEP make good gear, it's all tinned copper. I have BEP busbar in a more exposed location that's been there for about 16 years and it has just started corroding

When done and used appropriately, as well as supported and restrained properly soldering is fine. After all, it's how those plotters etc. are made inside after all.

But executing a soldered joint well will outside the skill set of many DIYers so I understand the advice.

It's not just splashing you need to guard against, just the salty air will aid galvanic corrosion (aka disimilar metals).

MikeAqua

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#2565553 15-Sep-2020 20:05

Yes that's pay much what the ABYC standards (which are for marine industry not DIY) say. If you must use solder then .... but a secure mechanical connection is preferable for wiring. Marine electronic components contain soldering, but almost entirely on circuit boards.

Properly tinned terminations don't corrode, unless there is direct saltwater contact.

If it ever stops raining, I'll post as picture of a shoddy 2004 installation with minimal corrosion.

Mike

andrewNZ

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#2565578 15-Sep-2020 21:23

The solution is to strip the wire more, twist and then double it enough times that it fills the crimp properly, then crimp it.

I wouldn't do the ferrule thing. There is a risk that crimping it in a lug would loosen it.
Flattening a ferrule is how I remove them when I don't have any length to spare on a wire.

Electrician.

Location: Dunedin

MikeAqua

6058 posts

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#2565651 16-Sep-2020 08:14

andrewNZ: The solution is to strip the wire more, twist and then double it enough times that it fills the crimp properly, then crimp it.

I wouldn't do the ferrule thing. There is a risk that crimping it in a lug would loosen it.
Flattening a ferrule is how I remove them when I don't have any length to spare on a wire.

If I understand correctly you are saying that crimping onto the ferrule may cause it to release the wire?

I did think about doubling the stripped wire up on itself, however it would have to be doubled 3 or 4 times. It's going to be quite difficult to end up with the correct length of exposed wire and doubled wire can't be trimmed.

Edit: I'm now thinking of sticking with ferrules, discarding the ring terminals and using a chocolate block type terminal. The challenge will be finding something marine grade.

Mike

andrewNZ

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#2565672 16-Sep-2020 08:55

That's what I mean in both cases, yes.

For correct length, strip at least enough, then starting at the insulation end of the stripped portion fold it long enough for the lug then back and so on. When it's big enough, trim the excess.

Electrician.

Location: Dunedin

MikeAqua

6058 posts

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#2565723 16-Sep-2020 10:27

andrewNZ: That's what I mean in both cases, yes.

For correct length, strip at least enough, then starting at the insulation end of the stripped portion fold it long enough for the lug then back and so on. When it's big enough, trim the excess.

Thanks, that's so simple I'm embarrassed I didn't think of it. I have a spare lead from a plotter that died, so I'll practice on that.

While I have your attention, what type of ferrule crimping tool would you recommend? (just in case I go down that path).

I can get ferrule dies for my ratchet crimper, but only two sided.

Mike

andrewNZ

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#2565736 16-Sep-2020 10:36

I only use a 2 sided crimper. Many of my workmates use the 4 sided one size fits all type crimper.

The much more important thing is getting the right size ferrule, or if you can't, making sure you fill enough of the ferrule that it makes proper contact when you crimp it.

Electrician.

Location: Dunedin

MikeAqua

6058 posts

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#2565753 16-Sep-2020 10:56

These are the wires I'm referring to. Overall diameter, including insulation is ~1mm. Actual conductor is ~0.5mm

Mike

andrewNZ

2326 posts

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#2565885 16-Sep-2020 13:10

It looks like a 0.5mm² pin (ferrule) will be fine, you'll need to try it.
I may not have expressed things clearly in the last post. Mostly what I was getting at is not using a 2.5mm² pin for 0.5mm² wire.
Here's an example. (terrible, not great, perfect)

Your conductors took a lot more substantial than I was imagining. Some that I deal with are 0.18mm², they're an utter pig to deal with.

Electrician.

Location: Dunedin

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