The 14ga/15Amp spec only applies to AC, not direct current. Wire for DC applications is sized based on the amp draw, the distance of the wire run, and how much voltage drop you can live with, which is 3% for most DC applications. Ther are charts all over the internet depicting this.
Bob Landry wrote: The 14ga/15Amp spec only applies to AC, not direct current. Wire for DC applications is sized based on the amp draw, the distance of the wire run, and how much voltage drop you can live with, which is 3% for most DC applications. Ther are charts all over the internet depicting this.
So you say wire for "DC" is sized based on "Amp draw, the distance of the wire run, and how much voltage drop you can live with." What criteria do you think are the used to size "AC" wire? What makes you think it is any different?
I agree with the "keep it under 15 amp" statement (for 14 ga) and you will be fine weather it is AC or DC. I am NOT an electrical engineer but I know a piece of 14ga copper will reliably and safely blow a 15 amp fuse or trip a 15 amp breaker as long as it is under any length that would reasonably be used in an RV.
sparkydave wrote: Well... No. Skin effect comes into play at high frequencies, like radio frequencies. At DC and low frequency AC power, stranded versus solid will make no difference. BTW, I'm an electrical engineer.
Oh and just to nitpick at it, just being stranded isn't good enough. Each strand has to be individually insulated or the current will only flow on the outside strands.
Chassis, house, mains theres a standard written? Maybe just a normal what we see nowadaze... Why there's no standard color code written between RVIA ,SAE, NEC is well beyond my scope of WGAC...
Bob Landry wrote: The 14ga/15Amp spec only applies to AC, not direct current. Wire for DC applications is sized based on the amp draw, the distance of the wire run, and how much voltage drop you can live with, which is 3% for most DC applications. Ther are charts all over the internet depicting this.
So you say wire for "DC" is sized based on "Amp draw, the distance of the wire run, and how much voltage drop you can live with." What criteria do you think are the used to size "AC" wire? What makes you think DC is any different?
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Wire for AC applications is sized for maximum load good up to approximately 100'.
15A - 14ga
20A - 12ga
30A - 10ga
50A -6ga
To answer your question why do I think it's different, I've been doing installing and servicing Marine 12VDC and Shore Power systems for 15 years. What are your qualifications?
This link will explain how to correctly aize wire for DC applications.
To answer your question why do I think it's different...
Bob, re-read my post please. I did not say that the wire size for a given load was the same AC or DC. I simply said the criteria for choosing a conductor was the same AC or DC. Those criteria, to quote you, are "based on the amp draw, the distance of the wire run, and how much voltage drop you can live with." Those criteria are the same for AC or DC. I never said the wire size was the same AC or DC.
Now, back to my original reply (which was to the original poster,) I stand by my statement "the 'keep it under 15 amp' statement (for 14 ga) and you will be fine weather it is AC or DC." Seems like a simple reply to a simple question posed by the original poster. The reason for this is that in my opinion when it comes to wire lengths relevant to an RV, the difference between AC and DC matters so little as to be negligible.
It seems that many others in this very thread feel that 14GA is fine for 15 amps in this case weather AC or DC. I am just one of those many posters, and I stick by that.
That link that Bob Landry posted here is telling me that for a 12 VDC, 15 amp load across a conductor 30 feet long with 2% loss, I need to use 000 (3/0) wire. That made me laugh out loud. It may very well be true, I have no idea. But back here on earth no RV'er is using wire that is several dollars per foot and more than 5/8" in diameter (each conductor) to run a couple lights and a fantastic fan.
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