17
\$\begingroup\$

I am running a 160amp DC current through a 1/0awg wire. Will the connection be more reliable with crimped connections, soldered connections, or screw terminals?

I have looked online and it seems that all of those connectors have their advantages and disadvantages, but for something with such high DC amperage what will be the best?

I would lean towards soldering because a good solder connection will not have any air, but I want to know if I am wrong with that thought.

\$\endgroup\$
27
\$\begingroup\$

For high currents and thick wires, a gas-tight crimped junction is the industry standard choice.

While solder appears to have its advantages, the key issue to keep in mind is the challenge of soldering 1 AWG copper wire, where the thermal conductivity of the wire itself will rapidly draw heat away from the soldering location, and insulation etc elsewhere on the wire would get overheated and damaged. Of course, for such uses, a blow-torch type gas soldering gun would be used instead of conventional soldering irons, but the issue remains.

Another concern with soldering is that the solder itself could potentially melt and run, leading to an all round mess, if the junction were to heat up enough, a distinct possibility at 160 Amperes.

Screw terminals would work, but the risk is of the terminal tabs coming loose over time due to mechanical vibration, and also of oxide formation at the metal contact surface, leading to increased resistance, thereby heat, and another all-round mess.

A crimped spade terminal actually creates a metal-metal colloidal bond at the surface between the wire and the terminal, and if done right, no gas remains between the surfaces. This ensures longevity and safety, making this the preferred mechanism in industrial implementations.

\$\endgroup\$
  • 1
    \$\begingroup\$ +1 for describing melting solder. Also, solder re-crystallizes with age, and any heat can help this process. Which increases the joint resistance... \$\endgroup\$ – Brian Drummond Apr 17 '13 at 10:27
  • \$\begingroup\$ I agree with this answer as the best solution. The problem is that tools to crimp a connector properly can be expensive, so for a one-off, solder may be a better choice than a poor crimp with an inferior tool. \$\endgroup\$ – lyndon Apr 17 '13 at 12:29
  • 2
    \$\begingroup\$ @lyndon Sure: So long as one is comfortable with the risk of a solder melting, then a high power electrical meltdown and possible risk to life, given the 160 Ampere current specified in the requirement. \$\endgroup\$ – Anindo Ghosh Apr 17 '13 at 12:32
  • \$\begingroup\$ What about terminals that have screw connections? so you put the wire in and then tighten a set-screw? Are those any good? \$\endgroup\$ – Sponge Bob Apr 18 '13 at 3:43
  • 2
    \$\begingroup\$ @KeeganMcCarthy I had somehow gathered that was the case. If you actually need to be handling such high currents, it might behoove you to pay someone at some industrial set-up or workshop to crimp you a set of wires. Safety is best not taken lightly when heat generation is proportional to the square of 160 Amperes! \$\endgroup\$ – Anindo Ghosh Apr 18 '13 at 3:49
-1
\$\begingroup\$

Definitely: a crimped connection will be best if properly done. One thing I have seen many times is that soldered connections create a critical point at the point where the solder ends on the side opposite to the terminal: the solder wicks between the individual wires of the cable, producing a very stiff zone where the cable's flexibility is lost... this point is very fatigue prone, and will break if the cable is moved or flexed or subject to the slightest vibration. Soon, the rigid solder impregnated part of the cable breaks and separates from the rest of the flexible cable! Instead of it, a very good approach can be used: A combination of connection types!

First throughly clean the cable end until shiny copper is achieved and pre-tin the very end of it with solder. Pre-tin the terminal lug but only at the place where the very end of the cable will end. Next slide several (at least two different sizes) pieces of heat shrink tubing that will serve as a "Strain-Relief". Then crimp the terminal as hard as you can with at least two sizes of heavy pliers. This crimp will stablish the MECHANICAL fastening of the connection. THEN, go to the very end of the cable and lay a small drop of solder to guarantee electrical continuity. Finally, slide back the thinner shrink tubing and heat shrink it with a hot air gun (using a lit match will most times burn and degrade the material). Then the next one, and then the largest one. To leave a neat, functional strain-relief made with two to three overlapping shrink tubing pieces, cut the pieces so that the thinnest one is a quarter inch longer, the next one a quarter inch less, and the thicher, final one should be the shortest. Using this method, I was able to tackle most Jobs even without the purchase of my heavy crimping tool. But in the end, after some years, I decided to buy a good quality crimping tool when I had to rewire an old car, requiring many crimps on terminal lugs. Some crimping tolos are not that expensive, and perfectly adequate for occasional use. The best ones are more expensive and will last for thousands of crimping operations. But with such a heavy size wire, a crimping tool will be very expensive... I would follow the method I described above.

\$\endgroup\$
  • 1
    \$\begingroup\$ I'm not sure you noted that the question is about 1 AWG wires and 160 Ampere current. 3 layers of shrink tubing, at that scale? Really? And pliers for gas-proof crimping of 1 AWG? \$\endgroup\$ – Anindo Ghosh Feb 25 '15 at 4:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.