beginner's DC wiring questions

[Buddy_Y]

Hi All:

Thanks to everyone for the great advice! I am taking Gord’s suggestion to go with 14 gauge for all the circuits exclusively (except for battery to DC panel) and to buy in bulk.

I am also going change my plans in accordance with GreatKetch’s advice and install a 60-amp breaker switch between the battery and the panel, so that it can double as a main power ‘off’ switch for ease in working, and in case of panel fire. As for his concern that my stern light is too weak—the light’s a standard one, it’s just my guess-timate of its amperage that was obviously off.

Just let me end by saying: it’s great being able to get advice like this online. Apart from the fact that it keeps a beginner like me from making expensive (or even dangerous) mistakes, it also spares me from doing the project plagued by the mental mantra “I’m doing this wrong… I’m doing this wrong….” Personally, I don’t find scraping hulls etc tiring at all; it’s the doubt and confusion that I find exhaustion.

Thanks again!

Buddy_Y

[Stenn]

That's ridiculous......it goes against every rule of good soldering practice I was taught in the military, and every other source I've ever seen, INCLUDING Casey's book referred to earlier in this thread.

Crimping alone allows for micro air-space within the connector, within / between the conductors themselves, and between the connector and the conductors as a whole. In the marine environment in particular, that's exactly what you want to avoid, allowing air and moisture, and especially salt-laden moisture, to get in there and start corroding the connection invisibly, from the inside, where you'll never see it til it's so bad it's "frothing" outside the connector with corrosion. Air, or to be more specific, oxygen, acts as a volatile catalyst to the electrolosis that naturally occurs between dissimilar metals, so eliminating as much contact as possible between oxygen and your conductors is critical. You do that by sealing it all inside solder, filling in all the micro air-spaces.

I can imagine someone might be making the electrolosis argument against introducing solder into the connection, the tin and lead in solder, and the copper conductor, and whatever connector you're using (copper, aluminum?) all being dissimilar metals. But allowing the existence of the oxygen in the micro-spaces between those dissimilar metals is what triggers the chemical reaction we call "corrosion."

Besides, the definition of "Marine Wire" is that it not only consists of an extra-tough, high-temp insulation jacket, and approx. 100 or more very flexible, tiny conductors, but that those conductors be "pre-tinned" as well, which is a layer of solder preapplied to every one of those 100 or more tiny conductors, to ease soldering "in the field," AND to protect those conductors from electrolosis/corrosion, through bonding their solder with the solder introduced by us into the connector.

So if that's their argument against solder, it doesn't "hold water."

That's the kind of condition Alan was warning about if using two separate conductors powering the same line, and using two separate connectors on each conductor....you multiply in spades the chances of having conductivity differences, and therefore differences in potential between the conductors, i.e. voltages set up BETWEEN the conductors powering the same circuit.

I'd SURE like to hear the logic behind NO solder, just crimp!

Stenn

[hellosailor]

Buddy-
Generally you would select a wire size that has no more than a 3% voltage drop for the intended load, for the round-trip length of the wiring run. While some of your loads (like the compass light) are trivial, you will probably find that it is cheaper to buy one large spool of "heavier" wire, than to buy bits of pieces of two or three different gauges. Typically wire spools are 100', 250', 500' and depending on the source, you may find that buying 100' of 14g wire is cheaper than buying 50' of 14g plus 50' of 16g. This also means that if you later want to run a heavier load--your wire can handle it.
Personally I would run the compass light and the nav lights and/or the insturment lights all on the same circuit, in the theory that you will want to turn them all on at once, or not. Fewer switches, neater panel, fewer connections to go bad.
Also note that in the US there are two common and different ways to measure wire gauge, SAE and AWG. Society of Automotive Engineers (SAE) gauges tend to run about one full size smaller than American Wire Gauge (AWG) wires for the same numeric gauge size. That's mainly because wire runs in cars are short, alternator voltage is 14.4 not the 12 from a ships battery, etc. Generally with boats we are referring to AWG wire gauges, you can buy SAE-rated wire but you'll need to go up one gauge size to get comparable wiring. And, while "car" wires are usually plain copper, you want "fully tinned" wire on a boat, because moisture gets sucked into the wiring and rots it out otherwise.

I'd also disagree with what most of the members suggest about fusing the battery primary wires. While a 160-amp fuse would be correct for protecting the cables, I'd look at this the other way around. A 160-amp fuse will be slow to blow, if it blows at all, under a lesser load. But since ANYTHING over 60-amps is going to mean you have a short circuit somewhere in the boat, and some other fuse hasn't protected you from it, I'm put a 60-100A fuse on the battery cables, knowing that it shouldn't blow unless there is an overload somewhere in the whole system. And if there is, it will blow faster, leaving the insulation less melted. (A conservative point of view.)
If those are the same cables that are used to electrically start the engine, and the fuse is inline with the starter as well, obviously it must be large enough to allow the starter's draw, too.

Stenn-
"Crimping alone allows for micro air-space within the connector, " Not if you use silicon grease in every unprotected crimp.<G> Or, for marine use, you use adhesive-lined heat-shrink crimps. Plain unsealed/unfilled crimps have no place on a boat. The argument against solder is that it creates the potential (pun ignored) for galvanic problems in the crimp and with the wire.
Which is not to say that I use crimping, or soldering, exclusively. I use both, and sometimes do solder a crimp--but not when I have the proper tools (adhesive lined crimps or silicon grease) around, and they are sized right for the job.

[Therapy]

Originally Posted by Stenn

That's ridiculous......it goes against every rule of good soldering practice I was taught in the military, and every other source I've ever seen, INCLUDING Casey's book referred to earlier in this thread.


I'd SURE like to hear the logic behind NO solder, just crimp!

Stenn

Well...............I just tried to do a search for that thread but the engine leaves a lot to be desired............so I did not find it.

BTW.........I did not write it, I read it.........

The writing was done by self professed knowledgeable folks with references to back it up........................

[Alan Wheeler]

I'd SURE like to hear the logic behind NO solder, just crimp!

Yeah that is a difficult one. And this topic is far bigger than jus the marine electrical industry. This point has been argued till blue int he face from both sides in the proffesional audio industry. There are differening opinions and both have there arguable good points. Personaly I solder.
Actually Sean, the military do both. I used a great deal of military multi pin connectors like CEE-MILL connectors etc. The big ones were 180 pins. They came mostly as crimp pins, but personaly I soldered them. The argument was that solder created a hard point at which the wire would fracture. This is true, but then movement should not be seen at the termination if the cable was clamped correctly. The issue for me was, if a wire did break, it was an easier job to unsolder all 180 terminations, dress the cable ready for resoldering and then carry that out. Crimped terminals meant you were throwing away a very expensive connector. I think a lot of that argument of solder vs crimp comes across from other industries. The Power generation and Transmission industry crimps. But the reason behind that is the conductors are to big to make soldering practicle. Some manufacturign industrys crimp, but that is because of speed on a production line, than any other argument. So I think much of the crimp methodigy comes across from other industries that use this technique. (Please don't take this as blowign my trumpet, not intended) I was at the top of my field in my proffesional carreer and I got to rub noses with the big wigs in the industry. I won't bore you with any more of that. But the interesting thing was, when we discussed this argument of Solder vs crimp, none could actually come up with a sound reason.
There is one important point however, that denotes if you should solder or crimp. The termination will be designed for one or the other. Make sure you use the right one in the correct way.
I asked a good friend the other day, "what do you do, solder or crimp?" . He replied, I do both actually. I crimp and then place a small bit of solder in the end to ensure the end of the cable is sealed.
Hellosailor, sorry mate, I have to disagree with the use of Silicon. Not good for the copper and it is very poor at keeping moisture out. The best thing to use is hot melt glue.

[Stenn]

I'm truly amazed to discover such division in something I thought was as basic and concrete as good soldering practice.

All I can say is, if it's good enough for the military aerospace and marine industries (according to Casey), and it's what I was taught 30 years ago in the Air Force and is still enforced today, I will continue to crimp AND solder. At work, we are required to crimp and solder by Mil-Spec, exactly to help prevent environmental stimulants to corrosion.

Stenn

[GordMay]

Crimp and Solder termination ARE permitted ~ Solder-Only terminations are NOT permitted.

Excepting for large battery lugs, with a solder contact length at least 1.5 x diameter (of conductor), ABYC prohibits Solder-Only terminations.
Crimped and Soldered connections (are permitted) must be located and supported to minimize flexing where the soldered solid* conductor transitions back to flexible.
* Solder wicks up the conductor, creating (in effect) a solid conductor.

I always seal terminations with adhesive-lined heat shrink tubing. If carried well beyond the solid-flexible transition, the heat shrink also provides some additional strain & flex relief.
Though permitted, I seldom crimp and solder terminations.

Panelboards must have an appropriately Main Breaker (or fuses), so the fuse mounted within 7" of the Battery is only required to protect the feeder cable (battery to panel). Since the Branch Circuit Breakers protect against overload, the prime purpose of the main fuse is to protect the cable against Short-Circuit. The principles of overcurrent protection “Co-ordination” require that the smaller (down-stream, nearest any fault) breaker/fuse should operate first (under overload or overcurrent), before any larger upstream device trips.

Accordingly, I recommend a High Interrupting Capacity Fuse, sized to the current-carrying capacity of the feeder conductors, be installed at the Battery.

Originally Posted by Therapy

There was another long thread a while back where a lot of folks had expert advice.
One piece of was that, for various reasons (and I cannot remember them all) one should NOT solder. Only crimp. No solder.

Therapy may have been referring to "Ohm's Law & Boats"
http://www.cruisersforum.com/forums/...boats-372.html
which does not proscribe solder and crimp.

[hellosailor]

Wheels, are you thinking of silicone seal? Or silicone grease? I've never heard of silicone grease reacting to the copper. I started using it after installing some instruments that actually shipped with a tube of it, giving me an "ahah" moment. I also used it for years on diving gear, covering the copper burst disk in my tank valves with silicon grease to make sure the seawater didn't corrode the copper (and let the tank drain unexpectedly). No problems in YEARS of contact.

I also can't see that you could put hot glue IN a crimp fitting, then crimp it correctly before the glue set up. Silicone grease doesn't impede the crimp, even if you get distracted in the middle of the job.

[GordMay]

Originally Posted by hellosailor

... I also can't see that you could put hot glue IN a crimp fitting, then crimp it correctly before the glue set up. Silicone grease doesn't impede the crimp, even if you get distracted in the middle of the job.

Electrical terminations are always moisture-sealed from the outside.
Only conductive anti-oxidants should be placed within the connection.

[Alan Wheeler]

silicone seal? Or silicone grease?

Arrr, yes I was thinking you were thinking Silicon seal. Silicon would be better, but as Gord has just stated above,

Only conductive anti-oxidants should be placed within the connection

So there we have two trains of thought once again. A company that produces instruments sayign do this, and another orginisation saying don't do this do that. The telephone industry use silicon grease in the terminations of all their copper wire connections.

[Therapy]

Originally Posted by GordMay

Therapy may have been referring to "Ohm's Law & Boats"
http://www.cruisersforum.com/forums/...boats-372.html
which does not proscribe solder and crimp.

No, and I still can't find it.
I think it was a long thread IIRC that went off on that tangent for a long time.

Oh well.

[Ex-Calif]

I know the follwing isn't 100% correct but neither is just running black and red wire all over the boat which can be confusing later. For most folks buying 12 different colored spools of wire to meet ABYC standards may not be cost effective either. I keep 5 spools of wire handy. All 14 guage.

Black - Grounds
Red - Power Unfused
Blue - Power Fused General
Brown - Power Pumps and Blowers
Yellow - Sense and data lines

I also agree with HS about wiring instrument lights and nav lights together. Our boat was a mixmash and I fixed it.

Current Switch and CB usage

Anchor light
Nav & Instrument lights
Cabin Power - lights, DVD player & fans
Fridge & Inverter
Autopilot & Depth
VHF

[Buddy_Y]

Here's my 2 cents on the soldering issue, in the context of terminals--actually, it's Don Casey's 2 cents, since I got this from the book I'm using. "Soldering: If you use tinned wire and tinned terminals, most experts agree that soldering is not required. However, if you do it well, soldering improves the electrical connection between wires and terminal. ... The only drawback to soldering crimp terminals is that solder in effect converts the stranded wire to solid. This is of no consequence unless the solder wicks beyond the barrel of the terminal, where it cases a hard spot that can be susceptible to fracturing from vibration."

Cheers

[Alan Wheeler]

where it cases a hard spot that can be susceptible to fracturing from vibration."

While this is true, there are common rules for installing cables. The weight of the cable should never come on the joint. The cable should be tied/held/suspended what ever, in such away, that the joint is protected from movement. Thus fracturing should not be able to occur. Plus, battery leads are so heavey, the ability of it fracturing is rather remote.

[GordMay]

Engine & Accessory Wiring Color Codes:
http://www.cruisersforum.com/forums/...codes-626.html

Wire Data:
Marinco Technical Support - How-to Guides