I'm contemplating wiring a small garden shed with 12v RV LED lighting, and using a solar panel to trickle-charge a lead-acid battery. Fuse or breaker protection is of course a good idea.
Are 120v/240v AC switches, fuses, and circuit breakers generally safe to use with 12v circuits?
We've had a somewhat similar discussion about a year ago, but that was regarding 120v DC. For this discussion I am only referring to 12v (13-15v nominal).
At 12v DC I would not expect the same arc extinguishing problems compared to 120v DC, so it in general looks to me like all 120v AC or higher fuses, switches, and breakers should be directly compatible.
I'm looking for some expert to jump all over me and tell my why this would be wrong, wrong, wrong, as I'm trying to follow best safety practices here for wiring a building with 12v LED lighting.
The goal is to be using standard-looking wall switches and wiring, in case there is ever a desire to switch from 12v DC to 120v AC power and not completely start over again rewiring everything.
If an expert would recommend higher current rated switches for DC, I am fine with that.
12 gauge NM-2 carrying 12v DC should apparently use the same current limiting as 120v AC, at about 15 amps, and for 10 gauge, 20 amps.
Voltage drop may be higher with 12v in standard AC wiring, but it does not appear to be enough of an issue to worry about in a shed wired with 12v LED fixtures, with wire runs of less than say 100ft / (30m) max.
This voltage drop calculator says that for a 100ft run of 12ga at 15amps (max) the drop for 13.6v is 10.42v:
http://www.calculator.net/voltage-drop-calculator.html
I have tried the LED fixture with a 9 volt alkaline battery and it illuminates acceptably to me.
Are 120v/240v AC switches, fuses, and circuit breakers generally safe to use with 12v circuits?
We've had a somewhat similar discussion about a year ago, but that was regarding 120v DC. For this discussion I am only referring to 12v (13-15v nominal).
At 12v DC I would not expect the same arc extinguishing problems compared to 120v DC, so it in general looks to me like all 120v AC or higher fuses, switches, and breakers should be directly compatible.
I'm looking for some expert to jump all over me and tell my why this would be wrong, wrong, wrong, as I'm trying to follow best safety practices here for wiring a building with 12v LED lighting.
The goal is to be using standard-looking wall switches and wiring, in case there is ever a desire to switch from 12v DC to 120v AC power and not completely start over again rewiring everything.
If an expert would recommend higher current rated switches for DC, I am fine with that.
12 gauge NM-2 carrying 12v DC should apparently use the same current limiting as 120v AC, at about 15 amps, and for 10 gauge, 20 amps.
Voltage drop may be higher with 12v in standard AC wiring, but it does not appear to be enough of an issue to worry about in a shed wired with 12v LED fixtures, with wire runs of less than say 100ft / (30m) max.
This voltage drop calculator says that for a 100ft run of 12ga at 15amps (max) the drop for 13.6v is 10.42v:
http://www.calculator.net/voltage-drop-calculator.html
I have tried the LED fixture with a 9 volt alkaline battery and it illuminates acceptably to me.