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Old 01-05-2013, 14:40   #91
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If a circuit were to get hot enough to melt a crimped or solder connection you have far bigger problems in your circuit then bad connections. I also have doubts a high resistance solder connection alone would get anywhere near hot enough to melt the solder.
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Old 01-05-2013, 14:48   #92
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Re: How do you Crimp #8 AWG Terminals?

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Originally Posted by evm1024 View Post

I picked 75 amps because it is roughly halfway between the inside and outside engineroom ampacity of a #8 105 degree C wire.

It does not alter the fundamental argument, but it can create the wrong impression when people talk about 8 gauge wire carrying 75A.
While the rating of a single 105c conductor in air is up to 80A (68A in he engine room). Once we put that in a conduit or bundle it with other wires the maximum continual rating drops to 56A (48A in the engine room) wire with 75C insulation is lower again.

The maximum current caring capacity on a boat is generally limited by voltage drop even if we are prepared to accept a 5% voltage loss a length of around 1.5m for both the + and negative wires is the maximum permissible length for 8 gauge carrying 75A (assuming the current carrying capacity is adequate)

Undersized wiring is one of the most common mistakes amateur (and unfortunately professionals) make and I wanted to dispel any unintentional impression that 8 gauge wire is suitable for 75A. It's not impossible, but very unlikely that it would be satisfactory.

I would hate to see great crimps on undersized wiring.
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Old 01-05-2013, 14:55   #93
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Re: How do you Crimp #8 AWG Terminals?

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Originally Posted by Reefmagnet View Post
If a circuit were to get hot enough to melt a crimped or solder connection you have far bigger problems in your circuit then bad connections. I also have doubts a high resistance solder connection alone would get anywhere near hot enough to melt the solder.
45 watt soldering iron melts solder.

How about hot enough to melt 105c crimp connector, and wire insulation?

Lloyd

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Old 01-05-2013, 15:13   #94
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Re: How do you Crimp #8 AWG Terminals?

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It does not alter the fundamental argument, but it can create the wrong impression when people talk about 8 gauge wire carrying 75A.
While the rating of a single 105c conductor in air is up to 80A (68A in he engine room). Once we put that in a conduit or bundle it with other wires the maximum continual rating drops to 56A (48A in the engine room) wire with 75C insulation is lower again.

The maximum current caring capacity on a boat is generally limited by voltage drop even if we are prepared to accept a 5% voltage loss a length of around 1.5m for both the + and negative wires is the maximum permissible length for 8 gauge carrying 75A (assuming the current carrying capacity is adequate)

Undersized wiring is one of the most common mistakes amateur (and unfortunately professionals) make and I wanted to dispel any unintentional impression that 8 gauge wire is suitable for 75A. It's not impossible, but very unlikely that it would be satisfactory.

I would hate to see great crimps on undersized wiring.
How nicely worded (truely)

The example as you noted is to make a point and to bring Georg Simon Ohm and James Watt into the conversation. One could run 75 amps through some #8 wire and have it work. But no one should think for a moment that running without a significant safety factor and properly sized circuit protection (fuse or breaker) is a wise thing to do.

Then again we are talking about using a hammer and screwdriver to make a crimp as something more than an emergency practice.

Regards

PS my favorite soldering iron is 18 watts and generates a 700 degree tip temp.
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Old 01-05-2013, 15:15   #95
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Quote:
Originally Posted by FlyingCloud1937 View Post

45 watt soldering iron melts solder.

How about hot enough to melt 105c crimp connector, and wire insulation?

Lloyd
so does a 15 watt iron. Totally irrelevant argument.
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Old 01-05-2013, 15:53   #96
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Re: How do you Crimp #8 AWG Terminals?

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so does a 15 watt iron. Totally irrelevant argument.
How is it irrelevant?

The melted terminals and wire that I posted the picture of were crimp connections. They were attached to the breakers, had they been solder only it would have melted the solder right out.

For the record a breaker will not trip on heat down line. Until the melted wire results in a ground fault. If no ground fault exist it will contiune until the wire melts in half or a fire starts.

This image is one of the breakers that were attached to the wires in the prior photo, not once did this breaker trip out.

Lloyd

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Old 01-05-2013, 16:38   #97
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Re: How do you Crimp #8 AWG Terminals?

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Originally Posted by FlyingCloud1937 View Post
This is an Anchor tool that will make UL approved crimps in a pinch.






Ancor 701010 Heavy Duty Lug Crimper

Item #: ANC701010

Details:

Spring loaded pivot bar, designed for use with a hammer or vise. Makes UL approved crimps. Capacity: crimps 6-4/0 AWG lugs and 6-3/0 AWG terminals.


Lloyd



$78.99 Ancor 701010 Heavy Duty Lug Crimper*-*Ancor*701010 - Ignition Tools and Testers - Ignition Parts - Engine/Mechanical - Boatersland Marine
OK, but it's irrelevant because the thread here is about crimping #8 cables. That tool won't handle #8 terminals and neither do the more common manual type.
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Old 01-05-2013, 16:52   #98
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Originally Posted by rwidman View Post

OK, but it's irrelevant because the thread here is about crimping #8 cables. That tool won't handle #8 terminals and neither do the more common manual type.
Indeed, no awg8. Also, when used with a hammer, the results are also unreliable, but when used with a vice it works pretty well for an amateur.
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Old 01-05-2013, 17:57   #99
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Re: How do you Crimp #8 AWG Terminals?

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Originally Posted by FlyingCloud1937 View Post
How is it irrelevant?

The melted terminals and wire that I posted the picture of were crimp connections. They were attached to the breakers, had they been solder only it would have melted the solder right out.

For the record a breaker will not trip on heat down line. Until the melted wire results in a ground fault. If no ground fault exist it will contiune until the wire melts in half or a fire starts.

This image is one of the breakers that were attached to the wires in the prior photo, not once did this breaker trip out.

Lloyd

Even if we forget for one moment that copper conductors conduct heat as well as electricity which allows them to quickly dissipate localised heating, lead solders only begin to start melting at around twice the temperature of 105 deg C rated insulation. My ad-hoc maths could be wrong, but I suspect this means that about 4x more electrical energy would be required before solder started to melt. It would take a peculiar combination of factors in a 12/24VDC circuit for this to occur imo.

The pictures you have shown illustrate exactly my point that there needs to be some other serious problem with the circuit. I'm guessing that particular circuit (which isn't 12/24VDC obviously) suffered from either/or: undersized wiring (my guess), corrosion at the crimps/connectors or overheating breakers.
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Old 01-05-2013, 18:43   #100
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Re: How do you Crimp #8 AWG Terminals?

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............. My ad-hoc maths could be wrong, but I suspect this means that about 4x more electrical energy would be required before solder started to melt. It would take a peculiar combination of factors in a 12/24VDC circuit for this to occur imo...
The heat could easily come from resistance in the connection itself. Enough heat to melt the solder.

There's no need to try to justify crimping over soldering, it is well known to be the best practice. Crimp, insulate if necessary, and move on. You're done.
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Old 01-05-2013, 18:55   #101
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Re: How do you Crimp #8 AWG Terminals?

When I converted to electric propulsion I knew I'd be making a number of crimps for various cables and battery interconnect jumpers. So I spent a couple of hundred dollars for the right tools:
THE BIANKA LOG BLOG: GOING ELECTRIC PART 18: Tools of the electric sailor.
I have not used them too much since my EP install but, I like knowing I could repair any connection that goes bad no matter where I am. You might be able to borrow or rent a proper crimper from a friendly boatyard. The right tool for the right job is really a good thing especially on a cruising boat.
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Old 01-05-2013, 19:22   #102
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Re: How do you Crimp #8 AWG Terminals?

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Originally Posted by rwidman View Post
The heat could easily come from resistance in the connection itself. Enough heat to melt the solder.

There's no need to try to justify crimping over soldering, it is well known to be the best practice. Crimp, insulate if necessary, and move on. You're done.
You might want to let these guys know that since apparently their business depends on it

Crimping Vs. Soldering For Cable Assemblies - Custom Cable
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Old 02-05-2013, 08:09   #103
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Re: How do you Crimp #8 AWG Terminals?

"For those who are proficient in their soldering skills, reliable connections can be achieved that are just as good as or even better than the crimped connections."

from the referenced link. "proficient, can be, just as good"

No mention if marine or other.
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Old 02-05-2013, 09:01   #104
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Re: How do you Crimp #8 AWG Terminals?

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You might want to let these guys know that since apparently their business depends on it

Crimping Vs. Soldering For Cable Assemblies - Custom Cable
I've done a number of things in my life. My summer job in High School was building Mil Spec versions of Tektronix oscilloscopes and other test gear. I've factually made millions of solder joints. I'm out of practice now but have skill.

To do a good job on a #8 wire would take a hefty iron - you need to heat the wire and lug quickly so as to reach the melting temp long before the flux burns off. And to prevent the heat from heading up the wire which will promote wicking and melt the insulation. You need to hold the wire and lug rigid till the solder solidifies. And then you need to clean the flux off.

All this takes time and skill. Then add in the supports to keep vibration from causing fractures.

I'm not saying that it cannot be done - Far from that. It just makes me wonder why a person would spend a minute or few soldering when a nice crimp tool does a good job time and time again in just a few seconds. To each their own I suppose.

Oh and by the way. I still do a lot of soldering. I build mic preamps and discrete op amps (Jensen 990s) and I use 2% silver solder which has a greater conductivity than plain lead/tin solder.

Regards
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Old 02-05-2013, 09:08   #105
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Re: How do you Crimp #8 AWG Terminals?

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I've done a number of things in my life. My summer job in High School was building Mil Spec versions of Tektronix oscilloscopes and other test gear. I've factually made millions of solder joints. I'm out of practice now but have skill.

To do a good job on a #8 wire would take a hefty iron - you need to heat the wire and lug quickly so as to reach the melting temp long before the flux burns off. And to prevent the heat from heading up the wire which will promote wicking and melt the insulation. You need to hold the wire and lug rigid till the solder solidifies. And then you need to clean the flux off.

All this takes time and skill. Then add in the supports to keep vibration from causing fractures.

I'm not saying that it cannot be done - Far from that. It just makes me wonder why a person would spend a minute or few soldering when a nice crimp tool does a good job time and time again in just a few seconds. To each their own I suppose.
Yes. Very few people would be able to solder a #8 cable to a lug in a workman like manner. I was an electronic technician for most of my career and did a lot of soldering. I'm good at it, but crimping is the approved way so that's how I do it.
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