Connection between mismatched wire sizes

[capn_billl]

One more thing, I dipped the copper ends of the wires in No-alox before crimping them in.

[Wotname]

Originally Posted by F51

Most people think the breaker is to protect the end equipment from catching fire, but that's not correct. The correct size breaker is to prevent the wire from overheating and causing a fire. Both Tellie and Mimsey are correct.

Originally Posted by goboatingnow

This isn't technically correct , this is just a "custom and practice" thing, CBs can be used at much lower rates then the wire can carry. I use them instead of inline fuses, which I hate. I have wires capable of carrying 30amps, with 5amp Cbs protecting the equipment.


Dave

Just to clear up this matter. The circuit breaker (or fuse) primary role is to protect the wiring and this dictates both the maximum rating of the breaker / fuse and its location in the circuit (i.e. as close as possible to the source).

Of course it is OK to use a lower rating as in Dave's example which then provides additional protection to the equipment.

Technically it is circuit protection you are after so the rating of the breaker / fuse should be rated so that if any part of the circuit is faulty, fire (or burnt out wiring) won't result. This is important in some pumps circuits where a faulty pump can overheat and catch fire without drawing enough current to trip the breaker. Here the correct rating would be that a little higher than that of the normal draw of the pump.

[hpeer]

FWIW, wire size works just like DB, a change of 3 = a doubling or halving.

Thus, if you take a 3" lead of 22AWG and double it over to 1-1/2" it is equal to an 18AWG wire. If you double it again, to 3/4" then it is equal to a 15AWG wire. So to make a 22AWG work in a Blue connector I have to double it twice.

If I double a 16 then it is equivalent to a 13.

Hopefully that will give you some practical idea of what it means to double the wire and when it really works.

[Tellie]

[QUOTE=GordMay;937353]Not really.
If using the Splice Cap Crimp Terminal c/w Splice Cap Insulators, I fill the cap with silicone, and heat shrink overall.
If the wire bundle isn’t very big (diameter) you might have to install a shrink over the wires first (prior to installing cap; to increase diameter so final o/all shrink will get a grip on both cap & wires).

Sometimes, I’d forgo the insulator cap, and just shrink (sometimes double) over the copper crimp sleeve, having filled the open end /w silicone.

The major downside of these crimps, is the need for (another) expensive crimper (Ideal/Buchanon #C24 @ ±$80).



Gord, if you are going to that extent to protect that type of splice why not just use regular wire nuts and do the same thing and avoid buying the crimp tool?

[Bestathook]

I noticed that only one poster suggested soldering the wires. Would someone explain why crimping is the preferred method?

Also, regardless of the type of connection, liquid insulation seems to work well to seal out water. Using several coats of Liquid Tape brush on insulation on acetone cleaned wires, I have even put a soldered connection under water, and gotten several year's service from it.

[DeepFrz]

Soldering locks the strands together and forms a hard spot at the end of the solder joint that will break from bending or vibration. Those that prefer soldering must use some method to protect the end of the solder joint from flexing.

[ssanzone]

Originally Posted by Bestathook

I noticed that only one poster suggested soldering the wires. Would someone explain why crimping is the preferred method?

when i solder, regardless of if both wires are the same gauge, i put 2 toothpicks inside the shrink wrap before i hit it with the heat creating a wire splint.

just have to make sure the shrink wrap extends beyond both ends of the toothpicks or the water will pool at the solder joint.

-s

[capn_billl]

Another problem with solder, If you don't get all the flux out it will corrode. And you have dissimular metals in contact so you have to keep it dry.

If you are good at soldering, and epoxy seal the joint, then it should be good to go. But crimping is easier, and faster, and just as reliable if sealed.

If you are an expert solderer, why did you ask? If not? Go with crimping.

[Bestathook]

When I used to maintain boat trailers, I noticed that crimps act as a funnel to lead moisture down into the joint. Many failures were the result of electrolysis between the copper and the metal of the crimp.

The crimps were easiest, especially on old wire that had turned black, and did not take solder well. If I scraped the wiresss, crimped them, and sealed them with Liquid Tape, no water entered. The liquid tape seemed to seal well, and make a waterproof joint.

Why do I ask? Because I am a youngster, a youth of 70, and still can learn from someone who has more expertise than I do.

[Opie91]

Originally Posted by btrayfors

Use adhesive shrink ring terminals -- properly crimped -- and small terminal blocks.

Bill

+1

This also allows you to easily add additional items to the circuit later.