Basic wiring questions

Discussion in 'Electrical Systems' started by fredscat, Oct 2, 2010.

  1. Ike
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    Ike Senior Member

    The equivalent you are looking for is UL 1426. There is mil-spec wiring but for boats the UL standard is the one the USCG uses.

    The USCG Standard says

    Sec. 183.425 Conductors: General.

    (a) Each conductor must be insulated, stranded copper.

    (b) Except for intermittent surges each conductor must not carry a current greater than that specified in Table 5 for the conductor's gauge and temperature rating.

    (c) For conductors in engine spaces, amperages must be corrected by the appropriate correction factor in note 1 of Table 5.

    (d) Each conductor in a multiconductor sheath must be at least a No. 18 AWG conductor.

    (e) Each conductor installed separately must be at least a No. 16 AWG conductor.

    (f) Each No. 18 AWG conductor in a multiconductor sheath may not extend out of the sheath more than 30 inches.

    (g) This section does not apply to communications systems; electronic navigation equipment; electronic circuits having a current flow of less than one ampere; conductors which are totally inside an equipment housing; resistance conductors that control circuit amperage; high voltage secondary conductors and terminations that are in ignition systems; pigtails of less than seven inches of exposed length and cranking motor conductors.

    Sec00. 183.430 Conductors in circuits of less than 50 volts.

    (a) Each conductor in a circuit that has a nominal voltage of less than 50 volts must:

    (1) Meet the requirements of Sec. 183.435; or

    (2) Meet:

    (i) The insulating material temperature rating requirements of SAE Standard J378; and

    (ii) SAE Standard J1127, or SAE Standard 1128.

    (b) This section does not apply to communication systems; electronic navigation equipment; resistance conductors that control circuit amperage; and pigtails of less than seven inches of exposed length.

    Sec. 183.435 Conductors in circuits of 50 volts or more.

    (a) Each conductor in a circuit that has a nominal voltage of 50 volts or more must be:

    (1) A conductor that has insulation listed and classified moisture resistant and flame retardant in Article 310, NFPA No. 70, National Electric Code;

    (2) A flexible cord type SO, STO, ST, SJO, SJT, or SJTO listed in Article 400, NFPA No. 70, National Electric Code;

    (3) A conductor that meets IEEE Standard 45.

    (4) A conductor that meets UL Standard 1426.

    (b) Where the nominal circuit voltage of each of three or more current carrying conductors in a duct, bundle, or cable is 50 volts or more, the amperages of each of those conductors must not exceed the value in table 5 multiplied by the correction factor in note 2 to Table 5 for the number of conductors that carry 50 volts or more.

    (c) This section does not apply to communication systems; electronic navigation equipment; resistance conductors that control circuit amperage; conductors in secondary circuits of ignition systems; and pigtails of less than seven inches of exposed length.

    The USCG standard for commercial vessesls says:

    (d) Cable and wire for power and lighting circuits must:
    (1) Meet Section 31013 of the NEC (NFPA 70), except that asbestos insulated cable and dry location cables cannot be used;
    (2) Be listed by Underwriters Laboratories (UL), as UL Boat or UL Marine cable; or
    (3) Meet 111.601 in subchapter J of this chapter for cable, and 111.6011 in subchapter J of this chapter for wire.

    As stated before you can get it from a lot of sources. Tinned is good but not required.
  2. CDK
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    CDK retired engineer

    There is a strong capillary action between the strands. To prevent moisture spoiling the wires, some use Vaseline, liquid neoprene etc., then put a shrink sleeve over the cable end.

    I use crimp terminals without isolation, heat them with a soldering iron and apply some 60/40 solder until I see it disappear under the edge of the wire's isolation. Tedious but very effective.
  3. Landlubber
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    Landlubber Senior Member

    ..Lanoline grease is the best product that I know of for a sealant at terminal ends, it stays there for the life of the boat, does not dry up nad works perfect.

    Covered with the 4:1 heat shrink with the glue inside it, the joints will never need attention.
  4. mydauphin
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    mydauphin Senior Member

    I run my cabling on the ceiling, not the bilges. My cables never get wet. They are easier to get to. I run them in conduits and I always run an extra line to every room. I run the water system in the bilge. Always had good result doing this.
  5. fredscat
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    fredscat Junior Member

    My layout allows a similar arrangement. Thanks
  6. tom28571
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    tom28571 Senior Member

    You can buy heat shrink tubing with the sealant already inside. The tubing provides stress relief which is a major plus on any vehicle system. Calder's book is very comprehensive but Charlie Wing's book is better for the novice to start with.
  7. fredscat
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    fredscat Junior Member

    Thanks for the input, will do
  8. DaveJ
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    DaveJ Senior Member

    You really need to sit down and plan out your wiring diagram even before you think about buy wire, below are some points to keep in mind.

    a. Current rating of the equipment
    b. Distance of equipment from current source
    c. Temperature of environment
    d. Type of environment
    e. Purpose of equipment
    f. How smart of a system do you want
    g. Easy to fix.

    There are plenty more considerations, but the major thing you want to know about a particular wire is to find out the maximum current rating for the equipment and times it by a factor of 1.5 as a safety margin for the amount of current the wire needs to carry. But you also need to look at the resistive value of the wire for the distance you are running it, if the voltage drops to low over the distance, then you will need to go up in current handling (which normally translate into less resistance), also the temperature rating for the wire and where its running (only really in engine bay is it a problem).

    Every time you make a join in a wire you are introducing an ingress point for corrosion, solder your joins and environmentally seal then. Like the guys said, solder your terminal lugs and seal with colour coded/or write on heat shrink for wire identification.

    Divide the electrical system up in groups like emergency, essential and aux. Make anything that is an emergency double redundant system. And if you have problems you can disable a group by its power board.

    I could go on more, but hopefully given you enough to realise what’s required.
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    FAST FRED Senior Member

    I have been told by a marine electrician that the terminals should be covered with shrink tubing and filled with some ??? anti corrosive "stuff" Any input on that? I am currently looking for AN (Army Navy) specs on marine wiring. Is there such a thing or is there a Coastguard equivalent?

    Look up IEEE45 for "approved" wiring.

    The folks with the most to loose from corroding wires is your local phone co.

    Really thin un tinned wire , high priced labor , and complaints about noise on the line.

    Simply ask an installer for a couple of hand fulls of their capsules .

    They shmeer a part of caps worth of goop in each wire to keep moisture out.

    Our way of creating good electrical connections requires a bit of extra work , but there has been no known terminal end failure in 40 years.

    WE chose good (anchor) wire , terminal ends and crimper
    .WE install and check that everything works as advertised.

    Then we disconnect all the ends from their posts and heat a 5 lb roofing copper iron .

    This holds MASSIVE heat , and the trick is to ONLY melt the solder inside the terminal end , not up the tinned wire.

    5 min of practice will let you see how quick the touch is.

    After there all touched , shmeer the phone co goop and shrink HIGH QUALITY shrink tubing 3X on.

    Aircraft folks and some boating supply places will have the heavy shrink wrap you need.

    The burgelar alarm folks have pads of stick on numbers , match the terminal ends to the posta or CB with numbers.

    Cover the numbers on the wire with "majic " scotch tape , and a SECOND set of ID numbers about a foot away (for future trouble shooting).

    Have fun,


    Then when there is a sufficient number of ends to do
  10. mydauphin
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    mydauphin Senior Member

    It takes a long time to do it right. Lay the backbone(main wiring first) then worry about doing the branches as you need them. Otherwise you might spend 6 months doing wiring and you don't see any progress. Make a diagram of where and how much power you need going everywhere but then redo it like a large house. I mean realize that a 92' foot boat is basically a 3 bedroom / 3 bath house. IT takes alot of wiring. Alot of amperage. Run those 10/3 everywhere for AC. Leave DC for navigation and emergency systems. Use biggest wires that is reasonable. I have 10/2 going everywhere for DC also. And used different color wrapped cable for AC and DC. Besides labeling I painted color codes of main runs so I can identify along the way. And remember there is alot more wiring coming for other systems, even cat5.
  11. sea_goin_dude
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    sea_goin_dude New Member

    I have been told by a marine electrician that the terminals should be covered with shrink tubing and filled with some ??? anti corrosive "stuff" Any input on that?

    Several tips here. Use the correct sized term for the wire size. Use a real crimping tool, not a pair of pliers or hammer chisel etc. The term hole must be same size as wire, not larger as the wire will not make a good connection and may pull out at later date. After proper crimp, use shrink tubing over connection and squirt a small amount of sealer, it will squeez all around the term and wire, like RTV or other electrical sealer. this will prevent water from working it's way back up the wire under the insulation to cause much corrosion and problems later. If running new wire, always leave a bit of slack, maybe a few inches in case you must replace the connector later and you won't have to splice additional wire to make the connect. After completing the new wiring, spray occasionally some electrical/electronics spray like silicone or WD-40 to help prevent attack on exposed terminals, screws etc.

    When buying wire, check with supplier to see if they may have some partial rolls and this may save you a bit of money, if you may only need less than a full roll. also you might get odd color wire also as a discount. If you are running any wire through conduit, always pull one or several additional wires, which may be any color and small gage to be used for pulling wires at a later date. This will prevent problems of having to try to push a pull (fish) tape through along with a bunch of wires. In stead of wires to pull with, you can pull several strands of pretty strong nylon cord through to be used to pull with if needed later. Just tie them off in the box/panel so they will still be available when they are needed :D

    Also when running any wires to accessories on the engine, like alternator,temp sensors, pressure sensors, always leave a good bit of slack to prevent the wires being damaged or broken due to motion of engine. Also be sure to clear any hot spots exaust pipes, manifolds etc. This will assure that your good wiring will last for many years and be trouble free for a long time. Always pays to do a good job now to prevent problems later. AND, a neat wiring job usually equalls a good, safe and long lasting, trouble free job.
    Good luck, hope this may help as these tips have helped me over the years to do a good professional job.:D
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    FAST FRED Senior Member

    The best product for terminal ends is FREE , from your local phone installer.

    With really thin copper , un tinned wires where corrosion creates noise , they use capsules of a goop that solves their problem.

    These by the box are on every phone truck , and un inventoried , so just asl a phone guy.

    Shrink tubing on top , after a ratchet crushed terminal ,and a touch with a big iron.

  13. Mark Cat
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    Mark Cat Senior Member

    I did the Electrical layout for a 74 ft Motor/Sailer Charter Aluminum Catamaran.

    The book titles provided in some of the posts provide good information, but are not comprehensive. Also not comprehensive are the regulating bodies like USCG, IEEE - 45, ABYC, ISO or UL1426. You must meet the Law CFR of course, and obviously if you want to eventually sell, pass inspections.

    But to really properly wire a boat of this size requires knowing all of the regulating body basics, but more importantly, knowing the other 80% which is knowing when and why we might want to go beyond a basic requirement, and what is really needed to make a safe maintainable installation.

    For example UL 1426 does not require tinning, or high type 3 stranding. ABYC really does not tell you how to size a circuit breaker. IEEE 45 - 2002, addresses single banking for cable ladders (trays) but does is not as detailed as ISO in keeping AC separate from DC.

    The budget for a 97 foot Cat is well massive. The electrical team alone is 2 engineers and 2 electricians, for completion in about 9 months. Shakedown requires 1 electrical engineer on-board for the cruise.

    A huge undertaking and huge money to get done in this lifetime.

  14. sdowney717
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    sdowney717 Senior Member

    Excellent wire for boats the gold plated standard except it is only tin
    copper wire is very very cheap, it costs more to buy the labor to install.

    you can use grade 2 multistrand, does not have to be fine strand number 3, does not have to be tinned, does not have to be bought at the boat store. You can goto Lowes or HD. Actually HD has some fine multistrand SO type cable, 3 wire, with black, white, green which is designed to be used for electrical tool hookup that I think would be fine. around 1.20 per foot

    Older boats may have solid romex from the factory. My Eggharbor 1970 37 does have solid core romex factory wiring installed for the AC circuits including a QO 10 breaker box. It used to bother me that they would have done this. BUT, since the boat is now 50 years old, none of the wire has broke rotted failed spectacularly, caused a fire, vibrated snapping off the ends, opened in the middle. The electrical boxes are all fiberglass standard shapes.

    The idea that romex solid core is going to be a disaster is not true, 50 yrs proved that to me. If I was to wire it up today, I would use multistrand number 2 in whatever various gauge sizes required. If the circuit was a 20 amp circuit, I would use 12 gauge, if 15 then likely still go with 12 gauge. A 10 gauge wire is simply waste of money on a 20 amp circuit.

    For cleaned oxidized copper stranding for soldering, I use white vinegar and rinse it off with water. So what ! vinegar is weakly acidic, cleans copper and has not caused any wire to internally disintegrate. If I solder I want a clean good wire to get a good solder tinning. Meaning put the end of the stripped wire in some vinegar, let sit a few minutes, brush it and rinse it. The purists would say buy an entire new wire run or just crimp. I have seen lots of severally corroded crimped multistrand copper with proper ring terminals after exposure to the sea air after a few years and they dont look good. Like you could trust them to not heat up passing a lot of current.

    Multistrand would wick liquid water so seal the ends. I typically use crimped ring terminals and self vulcanizing rubber tape. but unless it gets wet, it will be just fine.

    Self vulcaninzing rubber tape is rubber sticky when stretched and 1000% better than vinyl tape. So pull off a short section, peel off the backing, stretch it aqnd wrap it tight around the ends. Takes only an inch to do one end. The other thing I have used is liquid electrical tape in a can. then wrap the ends.

    IMO, all standards are an evolving process of greater and greater complexity and regulation till you reach the over regulated onerous burdensome area where only a few can afford to comply and vast majority go underground. Same applies to all human activity including business conditions. We regulate to the point of driving companies to go elsewhere and setup shop in china Vietnam etc...

  15. Stumble
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    Stumble Senior Member

    I am still convinced that were I to build a boat from scratch, or fully overhaul one I would install a distributed power buss system. It makes much shorter runs to supply, easier diagnostics, and easier installation. That being said the above posters have provided some very good advise.
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