why why wire gauge?

[limacina]

I'm rewiring my 1988 boat due to complete failure of the old switches and wires.<br />I've read West marine Advisor and a couple boat websites about wiring.<br />Why should I replace the 18 g lighting wires with the recomended 14g? I'd think the boat manufacturer figured out the safe wire to use. They didn't even use these tinned marine wire and it lasted at least 15 years. <br />I'll probabally never need to get the boat surveyed.<br />I was thinking 16g would be fine thru out and 12g to feed the fuse panel from the battery.

 

[Dunaruna]

Re: why why wire gauge?

A whole variety of reasons.<br /><br />Sometimes they get it wrong, sometimes they revise their reccomendations. New technology in cable manufacturing emerges, new techniques for crimping/soldering etc, etc.<br /><br />IMO, use what the manufacturer reccomends.

 

[crab bait]

Re: why why wire gauge?

if'n you only buy one size wire for general wiring,, best be 14ga.. it's 'the all purpose wire'.. other then feeds <br /><br />panel feeds should be no less the 10ga..

 

[vipzach]

Re: why why wire gauge?

I agree with the other guys, stick with manufacture recommendations. 14g is a good general size.<br /><br />I think that 12g is a little too small for the supply to the panels. I would go with 8 or 10g.

 

[18rabbit]

Re: why why wire gauge?

AWG 16 is the min wire gauge for boats. AWG 18 can be used as a jumper if totally enclosed in a panel. AWG 16 will handle almost everything on a boat. That is now the std gauge for rec boats. As others have already pointed out, AWG 16 will be too small for a feed to a distribution point.

 

[MrBigStuff]

Re: why why wire gauge?

Originally posted by Limacina:<br /> I'm rewiring my 1988 boat ... Why should I replace the 18 g lighting wires with the recomended 14g? I'd think the boat manufacturer figured out the safe wire to use.

Alot has changed since 1988. The number of electronic gizmos has increased dramatically and therefore so has the total power consumption required to fuel them. The increase in wire gauge is likely a response to this ever increasing appetite for power in all of our motorized vehicles.

 

[18rabbit]

Re: why why wire gauge?

MrBigStuff – welcome to the board. <br /><br />I believe the AWG 16 minimum has to do with vibration and the potential for smaller gauge wires breaking. A boat is one of the harshest environments for electronics, moisture, corrosion, and vibration, etc. Granted fresh water boating in a calm lake doesn’t compare with transoceanic crossing, but I think you get the idea.<br /><br />Oh, and you’re right, there are definitely more e-toys on a boat than ever before.<br />

 

[swist]

Re: why why wire gauge?

Some of it is simplicity - if you use #14 wire everywhere, then it can handle 15 amps - that's well within the usage of most boat accessories, and you don't have to worry about customizing the wiring type for each device. You only use larger wire for the exceptions: mains/feeds, bow thrusters, anchor winches, air conditioning and other stuff usually found only on large boats.

 

[18rabbit]

Re: why why wire gauge?

Good point, Swist. If re-doing the wiring, doesn't hurt or cost much more to just bump it up a gauge and you'll prob be covered for any future e-toys.

 

[limacina]

Re: why why wire gauge?

The issue of larger wire comes up when you try to fit it in the old runs and holes to conceal it as original.<br />Even using marine grade of the same gauge gets dificult since the insulation is thicker. <br />This is a Privateer boat, comercial grade. <br />With that said, my own conclusion before this posting was to upgrade to 14g for all systems and 10 or 12 to feed the panel from the batteries. <br />I feel a bit happier about placing the order with a few other opinions backing me. <br />It's a worth while post anyhow!

 

[Paul Moir]

Re: why why wire gauge?

Can you give us some idea of what the panel runs, and how far it is from the battery? #10 might not be sufficient to run the panel. You will want to keep your voltage drop at less than 3% and also leave room for the future.

 

[18rabbit]

Re: why why wire gauge?

Bubble poppin’ time!!! <br /><br />There is no such thing as ‘marine grade’ wire. Wire is made to spec for other industrial applications (corrosive environments, lots of vibrations, etc) that just happens to make it a good choice on a boat. Some distributors, like Ancor, have ‘marine grade’ printed on the insulation so they can target a specific market. Ancor even has “Ancor” printed on the wire they distribute. Ancor does not make any wire at all. And they don’t make any connectors, either. In fact, I believe Ancor doesn’t make anything at all! They became really, really angry when I called Ancor’s executive office and asked what, if anything, they actually manf’d.<br /><br />It is (virtually?) impossible to buy a piece of wire (or plastic that is used in electrical/electronics) that is not UL approved. I am not aware of any UL category specifically for marine applications. There are categories for other industries with corrosive environments that includes marine applications as part of the approval in the specific category.<br /><br />It’s the same for just about all of the other pieces of the electrical on your boat; switches, terminal blocks, connectors, etc. There are only two things that come to mind that may be manf’d specifically for boats; those L6-30P and L6-30R (30amp, AC shore power) with an external spin-on locking ring, and a series of AC 15/20amp duplex receptacles. Those receptacles are yellow and cost about $36+ each (compare to the ones in your home at $0.77 each). I am aware that those yellow duplexes are used in other industries, but the manf (Hubbell) specifically marks and markets those critters to the marine industry.<br /><br />Something else to consider, from a logistics perspective, everything electrical needs to be UL approved. The UL mark is not inexpensive, the marine industry isn’t large enough to justify the cost of UL approval for a switch that may be used on only a few boats, maybe 100 parts total. That alone will add an additional $150 ($50 x 3) to the cost of each switch. It’s possible someone in the marine industry is making inexpensive plastic trim or something like that to fit around an existing switch. But doing so is kind of a crap shoot because the UL mark is contingent on the item being stalled per the original manf’s instructions. Anything else and the UL mark is negated.<br /><br />EDIT: Just noticed on Ancor’s web site that “marine grade” is trade marked!!! As a result, only Ancor can supply you with “marine grade” electrical goodies for your boat.<br />

 

[MrBigStuff]

Re: why why wire gauge?

Originally posted by 18rabbit:<br /> Bubble poppin’ time!!! <br /><br />There is no such thing as ‘marine grade’ wire. Wire is made to spec for other industrial applications (corrosive environments, lots of vibrations, etc) that just happens to make it a good choice on a boat.

I thought the same way until I looked at their web site- it shows a marine listing for cable...<br />http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=BDFX.GuideInfo&ccnshorttitle=Boat+Cable&objid=1074078449&cfgid=1073741824&version=versionless&parent_id =1073984535&sequence=1

 

[18rabbit]

Re: why why wire gauge?

MrBigStuff - Really good find! I just received 1426. It is dated 1986, revised in 2001, so not likely to be a legacy std. It’s NOT for marine wire, it is for real, live, bona fide “boat” wire. It may contain specs that are a minimum for a wire to be labeled for use on a boat, but in reality no one is making product/wire to that std. That means wire is made to a diff std above and beyond the mins of 1426, but 1426 still exists for product marketing purposes. This is not uncommon.<br /><br />Fwiw, any wire intended to past 1426 investigation shall be labeled “boat cable”. If what you have doesn’t have those two words on it, it isn’t the stuff of 1426.<br /><br />A cursory reading suggests 1426 may exist in response to a std established by the NEC (Nat’l Electric Code) to define BC (boat cable), not necessarily UL. Now I’m curious if any wire manfr is submitting samples for 1426 review.

 

[limacina]

Re: why why wire gauge?

Paul Moir, The panel is running the 4 nav lights, 1 bilge pump, 1 to be added, a future blower, an accesories switch (which I probabally wont' run the electronics on,) wipers, and a horn. I have a seperate fuse panel for electronics, though on the same 10g feed from the battery.<br />The batteries are in the stern, the run is about 15 foot.

 

[limacina]

Re: why why wire gauge?

Ok, aObviously I agree with you guys about the importance of the right gauge wire but...<br />I bought a used trailer today and went to Walmart for new lights. Your trailer lights keep the the idiot in the minivan from rear ending you boat at a stop light. Pretty important ehh? You not only put trailer lights into a marine enviroment, you submerge them and their wire. Tail lights stay on for long periods at a time.<br />So why is it when you buy a trailer light kit, they are supplied with 18g plain old un tinned wire? it may even be copper plated steel wire.<br />Submerging this wire with the crappy connectors supplied is sure to wick water inot them. <br />The bulbs draw more than nav lights and the wire is longer and smaller than anything on your boat. <br />14g is good for pumps, blowers, wipers, and electronics; but nav lights and horns can handle 18g. A seperate roll of gray wire for this purpose wouldn't be unreasonable and you can ID these circuits easier.

 

[Paul Moir]

Re: why why wire gauge?

I think the 16 gauge requirement is for vibration, not for actual load. That is to say to keep the wire from falling apart. I don't know why trailers are always have crappy wiring which breaks all the time - just seems to be the case. Perhaps it the relation to automotive stuff.<br />I know the Canadian regs, but they're pretty much a direct lift of the ABYC boating regs - at least for electrical. They have a rule to allow you to identify wires (yes, there is actually a colour code rule) with coloured electrical tape at the ends of the wire. Probably there's the same for you.<br />Here it is - 8.7.2.2 If coloured tape is employed for colour coding, it shall be not less than 5 mm (3/16 in) wide and shall<br />make at least two (2) complete turns around the conductor in a visible location adjacent to the<br />terminal.<br /><br /><br />Ok onto the important stuff: nav lights are typically 10w (~1 amp each x 4), bilge pumps 2 to 10 amps (and up naturally). Blowers 5 to 15 amps depending on size. Wipers say 3 amps. Horns usually 3-20 amps or more. Say it's just a cheap normal (not trumphet) horn, 5 amps. Say also it's just a little bilge pump & blower, 5 and 7.5 respectively. Throw in 5 extra amps for the future accessories.<br />So total draw from this one panel is 4 + 5 + 7.5 + 5 + 3 + 5 = 29.5 amps.<br />Now the electronics, say 6 amps transmitting with a VHF. Fish finder I guess is a couple amps. Now we're looking at drawing pretty close to 40 amps over this 15' length of #10 two-wire. So what's the voltage drop?:<br />#10 wire - 12% (10.5v from 12, marginal running for most electronics)<br />#8 wire - 7.5% (11.1v)<br />#6 - 5% (11.4v at panel)<br />#4 - 3.3% (11.6v at panel)<br />Now all this stuff isn't going to be on at the same time, but a lot of it sure can be. The rule here (and probably the 'States too) is that our panel feeders must not drop the voltage any more than 3%. For you that would mean #4 at a bare minimum.

 

[swist]

Re: why why wire gauge?

Limcina: It's one of the mysteries of boating - trailer wiring is in general cheap junk (the fixtures, even the so call submersible ones, aren't much better). Much trailer wiring gets replaced a lot more frequently than need be.<br /><br />If you try to buy good trailer wiring components, you can't. I never understood this....