Wiring Basics

[Alie&Jim's Carrilite]

I have a question concerning stranded wiring-

In the boating industry, tinned, stranded wiring was normal for all wiring functions. It was a fine strand wire which bent easily, tinned so it was corrosion resistant, but somewhat expensive when you got to the bigger sizes and wanting to use 100's of feet.

In the RV industry, I see stranded wire for the 12v side of things but it is a bigger strand- less of them in the bundle- that makes up the gauge of the wire. Less strands = more resistance in the wire, possibly more heat at max amperage, etc.

That all being said now, does it make much difference if you're using the industrial stranded wire, but using it for 12v and only for LED lighting?

Lowes has the industrial wiring, stranded- in the usual sizes and colors. Most 100ft rolls are $30-50.

Where a marine grade wire from Ancor would be $75+ usually around a dollar a foot and up.

Am I missing a better source for wire for these side projects I have?

 

[Mark and Dale Bruss]

I use marine grade wire as a rule. Started when we had a boat and just kept using it when I rewired the truck and other projects on the trailer.

 

I prefer it for the flexibility and the corrosion resistance. The flexibility is a protection from vibration aging of the wire. It is manditory on boats. I think it should be required on RVs.

 

Marine grade costs a little more. I just paid $20.50 for 50' of #10 wire from Amazon.

[Jack Mayer]

I agree with Mark (and you) that ideally RVs would be wired with marine grade wire. But they are not. They use Romex and other non-marine grade materials. They also do not operate in a corrosive marine environment. But they operate in a vibration "rich" environment, and the marine grade stuff would be of .benefit there.

 

To directly answer your question - YES, you can use the wire you find in HD and Lowes for 12 volt LED wiring. Is it "perfect" for the application? I would say no - the marine would be better. But from a performance perspective I would not hesitate to use it, and I do.

[Alie&Jim's Carrilite]

Thanks guys. It just kills me to go buy what I had and sold not long ago. When we dismantled the business and sold everything, I sold literally hundreds of spools with thousands of feet of wire from Pacer Marine. Every size from 22 down to 0000 all tinned, in just about every color and stripe combination you could think of. I kept a nice assortment of connectors that I've slowly used as well. While I still have some sources for marine grade wiring and accessories- butt connectors, ring terminals, etc- buying in the bulk fashion I once did isn't really "affordable, packble, fulltimming friendly, whatever word I'm looking for here". I mean what would I do with 1000 of the blue heat shrink butt connectors, or the 5/16 heat shrink ring terminals.... unless I got involved in something like the solar rally which was a thought but I already spent enough $$$ this year.

Off to Amazon to get ripped for 25ft of #8 Red and Black. Need to add a fuse block for all the camera wiring, TST monitor wiring, and change some of the existing modification done to the truck.

[oldjohnt]

Jim, First of all, if 12 Gauge wire etc. is still 12 gauge regardless if its a single conductor or coarse stranded or fine stranded, it has to do with the total conductor cross sectional area. A wires rated ampacity has to do with is that amount of current it can pass (and in what environment and enclosure or raceway etc) and sufficiently dissipate the heat so as to not degrade the wire or insulation.

 

In many RV applications non metallic sheathed multi conductor cable such as 12 or 14/2 w/ground "Romex" is used for the 120 VAC distribution while stranded wire typically 12 or 14 AWG is used for 12 VDC distribution.

 

 

As far as 12 VDC distribution, if money were no consideration whatsoever, for RV use I would choose a fine strand such as that approved for Marine use where fairly extreme vibration is present. However, many RV's are equipped with regular grade (less flexible, coarser strands) yet still flexible stranded wire.

 

That being said if I chose the regular grade of coarse stranded wire (likely what I as a frugal person would purchase) for RV use I WOULD USE FLEXIBLE LOOPS AND EXPANSION LOOPS WHEN WIRING such as a loop between where the wire was attached to the RV frame and where it entered a junction box or light fixture or appliance. That wiring method will allow for flexibility and vibration and render less flexible cheaper wire to act more like more expensive more flexible (finer strands) wire.

 

Of course as Im sure you're well aware protect the distribution conductors at their source (such as the DC distribution/fuse panel) with an appropriate overcurrent protection device (like 20 amp fuse for 12 gauge or 15 amp for 14 gauge) and I always sized the conductors ampacity to be 125% of a branch circuits maximum continuous load, i.e if the max load was 16 amps I would use wire rated for 20 amps, but if more then 16 I would upsize to 10 gauge.

 

BOTTOM LINE marine grade is better but regular grade will suffice just fine however I would use ample flex and vibration loops throughout as an extra measure of protection.

 

John T Too darn long retired Electrical Engineer and rusty on the latest codes and procedures so NO WARRANTY

[Kirk W]

Given both types being available I'd take marine every time, but when buying it I more typically use automotive grade which is more readily available and for a lower cost. RVs are bought based so much upon the cost that I understand the manufacturer not using marine grade wire. The automotive industry doesn't either, even when under the vehicle and exposed to weather. The only place that I usually go find marine grade wire if not available is in areas where it is exposed to weather or some other corrosive problem, like to the light plugs between a tow vehicle and trailer.

[Jack Mayer]

Jim, just to clarify my answer. I would use the regular HD wire. The benefit gained from using marine wire is minimal in the environment you are talking about (interior 12 volt low current application). AND the entire rest of your RV is wired with non-marine wire. You really gain nothing significant by using marine grade. Of course, it goes without saying that you use the correct connectors and wire size.

[Scrap]

I buy SXL or GXL most of the time and maybe TXL if I'm trying to keep the harness small and it isn't under the hood. I bought one of those ebay shrink wrapped donuts awhile ago because they are a smokin deal. But I opened it wrong and still have a 1000ft long hairball I need to deal with in the bottom drawer of my toolbox. So careful with that...

[Alie&Jim's Carrilite]

I here ya Scrap, I too have bought one and didn't exactly follow the directions... I ended up just cutting out what I needed as I needed it. Gave the rest to somebody when I cleaned out the garage at the house..