Wiring: When 'just right' is too big??

[Judith]

After a number of discussions and liberal libations, we have tackled our wiring problem(s). We are replacing all the mast wiring, both in the mast and inside the cabin. Everything else seems to be OK, although we're cleaning up the panel, e.g., adding a new terminal strip so the ONE ground post will no longer look like two wrestling octopi trying to pin one another. . .

Thanks to encouragement and tips from this board, we HAVE got all our new wiring pretty much in place. The problem is, we're doing this based on Don Casey's recommended specs, and--compared to what was there before--our wires are HUGE: think spaghetti (old: 14 gauge, we think, and very skinny coax) compared to penne (new: 12 gauge + 1/2" dia. coax).

Inside the boat, that has simply meant enlarging the existing passageways or making new ones. We're having a problem, though, with the triplex that goes up to the existing combo steaming/deck light fixture at mid-mast. The terminal screws in the Aqua Signal fixture are teensy; the wiring is big and fat (and at one point, we need to get TWO wires onto a tiny screw. . .). Does anybody have a suggestion on how to make this work?"

[Oswego John]

Judith,

Check out the variety of crimp terminals. Usually flat ring or open (forked) terminals are flat enough to put several conductors under one terminal screw.

Another thing that can be done is to splice both conductors to a third tail. The tail (smaller gauge) can attach to the contact screw.

Good luck.

O J

[Judith]

Thanks!

[Duncan]

...The problem is, we're doing this based on Don Casey's recommended specs, and--compared to what was there before--our wires are HUGE: think spaghetti (old: 14 gauge, we think, and very skinny coax) compared to penne (new: 12 gauge + 1/2" dia. coax)....

The Twelve Volt Bible agrees with that. In fact, they recommend 10 gauge (canneloni? ) for 5 amps over that sort of (round-trip) distance (40-60 ft). This would result in a 3% voltage drop, so 11.64 volts. You can use smaller wires, but that will give you more voltage drop.

...The terminal screws in the Aqua Signal fixture are teensy; the wiring is big and fat (and at one point, we need to get TWO wires onto a tiny screw. . .). Does anybody have a suggestion on how to make this work?"

I would use a pair of ring terminals on the screw.
If 10-12 gauge wire won't fit in the other end of the terminals, fit in the biggest size you can. Then cut those wires short and join them to your 10-12 gauge wires with Step-Down Butt Connectors.

Makes sense?

[Maine Sail]

If you go LED nav lights you can reduce the wire size. I would not reduce the VHF cable though..

This is one of my favorite on-line calculators. it sizes marine wire..

http://boatstuff.awardspace.com/awgcalc.html

[mgphl52]

Judith,...

Another thing that can be done is to splice both conductors to a third tail. The tail (smaller gauge) can attach to the contact screw.
O J

If you do the "splice" I would recommend soldering the joint well. Heck, I would also do that with crimp connectors on the mast since you probably won't get a chance to check them carefully for some time... (ain't it great sailin' in FL... )

-michael

[Steve Laume]

Didn't I read somewhere that crimping, without solder, was now preferable to soldering marine electrical connections?

Those crimp connections with the heat shrink seem like they would be just the thing if you had to make a splice at the mast, Steve.

[Warren S]

I would be interesting in any supporting info in Steve's observation. Given that Type III (solder-tinned) cable is specified for marine environments, I naturally am convinced that terminations should be soldered...

[Oswego John]

I would hope to never be accused of any objection in regard to soldering electrical terminals. I think that it is also proper to mention, at this time, the merits of a properly crimped termination by a quality, calibrated crimping tool. The following thoughts are not to say that one method is better than the other. There are mostly pros and a few cons concerning each way. The most common fault, in my estimation, is a "cold" solder joint, especially in electronic wiring. Very hard to detect with the naked eye.

Both methods are accepted, the choice usually being predicated by the particular job specs. Many jobs under the aegis of both governmental and private industrial standards both allow and encourage crimped terminations. Crimped, as well as soldered terminations are permitted by NEC (Elect. Code) and AEC.

The major problem with using soldered joints is the type and amount of heat applied. A dry heat should be used, ie an electric soldering gun or a pencil tip iron. Avoid open flame heat. Soldering flux must be used. Excessive heat can produce cupric oxide which will compromise the joint.

A common method of wiring a fixture, mentioned earlier, is to use a fixture tap. This is accomplished by splicing the heavier load bearing wires together with a smaller gauge wire (fixture tap). The small wire attaches to the fixture while the larger wires maintain the load without endangering any voltage drop.

A word of caution. When wiring a mast or anything subject to vertical gravity pull, at each fixture location a method of mechanical support should be incorporated to suspend the weight of the conductors while allowing the splices and termination points to remain free floating.

I highly recommend that you review a compilation of good, bad and ugly mechanical crilping tools forwarded to us by Maine Sail. I consider it a very comprehensive, educational and informative review. Thanks again, Maine Sail.

http://www.pbase.com/mainecruising/wire_termination

O J