No Shore Power on Board

capta

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Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
It depends on the frequency whether or not the current flow is restricted to the exterior of The Wire. That's why many radars use waveguide. They eliminated the interior of The Wire all together. At low frequencies, AC probigation is about the same as DC. That is why stranded wire in a given gauge and solid wire of a given gauge have the same ability to conduct current in normal 60 hertz circuits.

Once you get up into the gigahertz range now you have to worry about the surface of the conductor.

Ken
Then why am I spending all that extra money on tinned 'boat wire' for my 117 vac and 12 vdc wiring?
 

capta

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Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
That's back to the vibration and corrosion issues that uncledom mentioned.
No way I'd use solid copper, but there are plenty of quality multi-strand copper wires on the market. And plenty of anti-corrosion goos on the market to limit corrosion at the connections, all of which would still come out way under the cost of tinned boat wire.
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
i did not understand any of this. i'm learning. electricity is much like a magic trick to me. never solid except in houses. just spent an hour talking to a retired lineman from the local power company.
we also ride our BMW bikes all over the country. last month was the back roads of west virginia. it was a WOW
 

capta

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Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
i did not understand any of this. i'm learning. electricity is much like a magic trick to me. never solid except in houses. just spent an hour talking to a retired lineman from the local power company.
we also ride our BMW bikes all over the country. last month was the back roads of west virginia. it was a WOW
Ever since I laid one probe of a VOM on a made bunk on a wooden boat and put the other into the positive side of a 12 vdc outlet and read 2.3 volts, I've called it electrickery.
 
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Brazil

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Aug 16, 2017
26
Hunter 37C Forked River, NY
Having just rewired my mast, I've been wondering about the solid/stranded choice also. The old wire was non-tinned, stranded. After 38 years in service, not too back. I'm also gradually changing out wire to many other circuits, finding corrosion everywhere.

The tendency for solid to break due to high vibration seems related to a work-hardening mechanism. That requires repeated flexing or stretching. For conductor locations that are fixed and supported, i.e. they don't bend anywhere, there should be no work-hardening. The earlier explanation of surface conduction related to high frequency is very helpful. (Things like eddy currents at high frequencies push electrons around.) At DC and 60 Hz, the conduction is through all of the conducting material. But corrosion comes in from the outer surface. As a surface corrodes and becomes insulating, there is less conductive material. The stranded, however, has much more surface area to corrode than solid. For the same depth of penetration of corrosion, the solid retains much more conductive material. I'm not the one to argue with the ABYC, but I suspect that runs subject to motion and flexing, even if only a small angular deflection, would be better off stranded, but conductors that can be permanently supported with no flex would be better off solid. Of course, your insurance company will hear none of this. Disobey the ABYC at your liability peril.
 
Oct 24, 2010
2,405
Hunter 30 Everett, WA
boat
Then why am I spending all that extra money on tinned 'boat wire' for my 117 vac and 12 vdc wiring?[/QUOT]
"Boat wire" is usually nickel plated (resists corrosion) and stranded (Which resists breaking with vibration). It often also has quality insulation that should last a long time and resist abrasion.

Ken
 
Oct 24, 2010
2,405
Hunter 30 Everett, WA
It's easy to see the difference between solid and stranded wire in terms of breaking. Just do this:
Make sharp bends in solid wire and count the number of times you can bend it before it breaks. Now try it with stranded. You should get the idea pretty quickly. Unplated solid wire takes longer to corrode through than stranded because it has less surface area, but as soon as you nickel plate it, the corrosion becomes less of an issue. Now mechanical breakage is much better with stranded. On a boat, I will always go with plated stranded wire. The same goes for aircraft. Your home isn't normally subject to vibration so solid plain copper works well there.

Ken
 

capta

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Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
We can get everything you described, as I mentioned above, except the tinning, plus a dielectric for a whole lot less, so why is the 'boat wire' the recognized standard? And one member is saying solid wire is just fine, too. Golly gee, the money the rest of us are wasting, apparently!
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
with my old alden i am resistant to change. i want to always try to keep the systems true to their vintage. old designs with modern upgrades are not my choice. this thread has been a nice eye opener for me. tinned multi strand wire is clearly the only way to upgrade. when changing things i only want the best. my vessel was built by paul molich in denmark using only the best materials from it's time. except for the chain plates, they were all replaced a long time ago. and they were easy to change compared to most. also, fresh water home for the boat is nice.
aeolus was called a one tree boat. all the wood on the vessel came from one tree so the grains match throughout.
the nice thing about change in wires will be that they are hidden. just like my GPS. i carry one, but not out in the open.

nicks and scratches in the wood we call patina. i hear patina on old things make them worth more. :)
 

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Therefore, many thin strands are going to carry more electricity with less resistance on their surface area than a single strand
Not a concern at 60Hz. Skin depth at 60Hz iz 8.5mm. Since a single, solid 14ga. conductor is only 1.6mm in diameter, there is no skin effect. The only reason for stranded at 60Hz down to DC is for flexibility.
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
so here is the answer i recieved out of JPL. DC current runs through the whole wire. AC current runs in a 'skin effect' at very high frequencies the current is on the surface only. at low frequencies it runs into the wire as well. it is determined by a 'function of the square root of the frequency'. the ac current flow creates eddies within the conductor forcing flow to the skin. nickle is a horible conductor.
as jviss wrote, our marine wiring will be using the whole wire.

fun fact: my brother got razzed by his boss for not remembering such from his basic engineering courses some 45 years ago. he retires this aug 2nd. he is a communication specialist on our deep space satellites.
 
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Jun 11, 2011
1,243
Hunter 41 Lewes
The fact that AC cycles back and forth is in it's self movement. It's minuscule but still it is movement and is part of the "hardening" process from constant vibration, 120 times per second. I have felt vibrations in wires at medium voltages and high amp load vibrate between my fingers and that is with a gloved hand. May or may not apply on our boats but I always feel my boat deserves the best I can do, so usually I go a little over board rather than skimp.
 

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
The fact that AC cycles back and forth is in it's self movement. It's minuscule but still it is movement and is part of the "hardening" process from constant vibration, 120 times per second. I have felt vibrations in wires at medium voltages and high amp load vibrate between my fingers and that is with a gloved hand. May or may not apply on our boats but I always feel my boat deserves the best I can do, so usually I go a little over board rather than skimp.
That is the wackiest thing I've read in a long time. And you're saying that not using stranded wire for AC is "skimping?" Really?
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
The fact that AC cycles back and forth is in it's self movement. It's minuscule but still it is movement and is part of the "hardening" process from constant vibration, 120 times per second. I have felt vibrations in wires at medium voltages and high amp load vibrate between my fingers and that is with a gloved hand. May or may not apply on our boats but I always feel my boat deserves the best I can do, so usually I go a little over board rather than skimp.
Sorry, not buying that. Electrical current is movement of electrons between atoms but not the atoms themselves. There's not really any movement there. Also if wires work hardened from AC current then stranded wire would be recommended everywhere, not just in vibration prone areas like boats. Im guessing what you felt is your nerves picking up EM fields from the alternating current, or the current itself if not adequately insulated. I've felt it too in the form of a minor shock from improperly grounded appliances, but that's not the wire moving.
 
Jun 11, 2011
1,243
Hunter 41 Lewes
Let me clarify. Medium voltage by definition is any thing above 240v and below 26kv. So it's a lot of voltage. The situations I have seen have all been at 480v and near or just above the amperage limit for the wire. In some cases I'm pretty sure the breaker should have tripped but that's another story. The wire physically moves! You can see it and if you touch it, you can feel it. You can't stop the vibration from touching it. It's actually pretty wild. You need to be fully dressed in appropriate PPE to even be in this area of approach to such voltage and current. I have been bitten by 277v which is one 480v leg to ground or neutral and I surely know the difference. This is what I do for a living. I have seen water boiling in a man hole from conductors that have lost insulation and the breaker does not trip as it's enough resistance to be seen as just part of the load. I have also seen this action in circuits that have tripped and been re-energized by simpletons that think it's ok to throw a load back onto a broken circuit. The wire near the breaker will actually jump right as the breaker is switched on and then instantly trips. Breakers don't normally trip for no reason and just resetting it without know why it tripped is always bad. Not asking you to buy anthing @Davidasailor26, the story is free. :D
 

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
I thought you said this was a problem on boats. Are you running "medium voltage" on your boat?
 

walt

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Jun 1, 2007
3,511
Macgregor 26S Hobie TI Ridgway Colorado
Admittedly splitting atoms here.. but voltage between wires creates an electric field and current in the wires create a magnetic field. Both of which cause a mechanical force between conductor wires that modulates at 60 hz for wires carrying AC.