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-   -   Wiring Gauge (http://www.fiberglassrv.com/forums/f55/wiring-gauge-25554.html)

D Shubel 05-08-2006 01:32 PM

My Burro is an empty shell of which I will be replacing everything.

I'm getting ready to wire my Burro so that I may take it down the road to the local fiberglass place to attach the floor to egg. I need to wire converter/charger, taillights, led lights, fantastic fan, 3-way refrigerator, 12 volt plug, 120 plugs, and would like future leads to possible A/C and undercounter instant hot water heater.

I have a copy of the wiring diagram from Scamp website that will be helpful in determining which color wires go to which component but I have no idea what guage wire to purchase for the components listed above.

Help http://www.fiberglassrv.com/board/st...lt/confuse.gif

colin k 05-08-2006 02:26 PM

I myself would wire all lights , 12v plug with 16 guage. Fan with 14 guage.Converters ,fridge,water heater 10 guage. All 120 run 3 conductor lumex from a small panel.

AC i have no idea. If ac is 120 then lumex. If its 12v then 10 guage. I would also fuse each run. Lights have a fuse. heater has a fuse, etc.

Bigfoot Mike 05-08-2006 03:34 PM

For what it is worth, a couple additional points to consider.

1) I added a three strategically located 12v outlets and really like them.
2) Any outside and kitchen 115v outlets need to be GFI.
3) Short runs and larger wire is better for Frig. if your frig. can run on 12v. while traveling.
4) Connetions in 12v creates voltage drop. Less is better.

I hope this helps, Mike

Darwin Maring 05-08-2006 03:59 PM

I use 12 gauge wiring for everything. Any weight saved by using a smaller gauge just is not that important to me.

DC voltage looses power over short runs and the thicker 12 gage wire helps to lessen the loss.

12 Gauge for the Alternating Current should be more than sufficient for everything up to and including a 5000W air conditioner, a 1500W heater rod in the water heater, additional electric heaters in the egg provided you have separate runs and fused for each.

Ground Fault any outside AC receptacle and make sure you have a ground on all AC applications, every where else.

AC for the water heater even if you do not have a electric heater at this time because someday you will want to insert a 110AC Volt heater rod inside your gass heater to suck up the free power at camp grounds.

Fuse everything, both DC and AC.

Make sure you mark the various cables so you can't get them mixed up and be sure all of them are secured so they can not be rubbed through or accidentely penetrated to cause a short.

Run 8, 10 or 12 gauge for electric brakes. For me, the bigger the wire the better for the brakes.

Brian B-P 05-08-2006 06:45 PM

Here's a recent discussion of this topic:
Help adding a 12 volt system to a scamp 13, Please help a newbie.

I'm sure Darwin meant 5000 BTU/hr (not watt) air conditioner. In a house, loads up to 15A use 14-ga wire, with 12-ga required for 15A to 20A (for instance); to me it makes sense to just continue to follow those same standards for the same type of equipment and cabling operating at the same voltage and current in the trailer.

Since a single axle electric brake setup only uses about 7 amps maximum, I placed connection reliability and wire protection well above wire size in importance when making my brake wiring choices.

D Shubel 05-08-2006 08:01 PM

Thank you so much for the great information! http://www.fiberglassrv.com/board/st...lt/bowdown.gif

So, if I went with a heavier wire (with fuse) the electrical component is not at risk? Because it would "draw" the electricity rather than the battery "sending" the electricity (possibly more than it could handle) through the thicker wire?

And one last question...when I decide on the wire guage, will it be clear which size fuze to get?

Joe MacDonald 05-09-2006 07:11 AM

when doing any trailer wiring, I generally follow the same current limits as household wiring, and I have never had a problem.


#14 wire- good up to 15 amps
#12 wire- good up to 20 amps
#10 wire- good up to 30 amps
#8 wire- good up to 40 amps
#6 wire- good up to 60 amps

usually anything requiring a fuse will tell you what size fuse is required

Darwin Maring 05-09-2006 09:50 AM

Brian is correct, 5000BTU on the air conditioner not 5000W. (My Bad) http://www.fiberglassrv.com/board/st...efault/shg.gif

Brake wiring: I make exceptional good connections using a western union, soldered, shrink wraped and double grounds. I have found in the past that faulty grounds are a major cause of problems in all trailers and all vehicle tail lights.

Over kill in the wiring size will not hurt however undersized will. J

14Gauge wiring in your house. We built our own house and wired it with a minimum of 12 Gauge and even 8 and 10 gauge to high load areas like the kitchen counter tops where tosters and other high wattage appliances are used.

Don't forget to add power locations for the propane, monixide and smoke detectors.

I added 12VDC waterprof receptacles (WalMart) to each side of our Egg, close to the tires so I can run a portable air compressor without having to run 15 feet of wire to a cigerate lighter in the truck. Also installed one in the rear.

You can't be too safe. http://www.fiberglassrv.com/board/st...efault/h45.gif

Brian B-P 05-09-2006 05:03 PM

Quote:

...So, if I went with a heavier wire (with fuse) the electrical component is not at risk?...

And one last question...when I decide on the wire guage, will it be clear which size fuze to get?
The part at [b]risk with inadequate wiring is the wiring itself, or really its insulation, which can overheat and fail.

A much less important effect is that undersized wiring will cause too much resistance, which causes too much [b]loss of voltage (as Darwin mentioned), which means less left to run whatever is using the power, which then might not work properly.

When the current is determined, the minimum wire gauge is known. When you pick a wire gauge, you have determined how much current can be safely carried; the [b]fuse (or circuit breaker) must be rated at a high enough current to allow the device (light, appliance, whatever...) to work, but always no higher than the wire is good for. The fuse can just be picked to match the least capable wire or connector in the circuit (see Joe's ratings, for instance), unless the device needs the fuse in the circuit to be no more than some maximum size.

For [b]example, if a refrigerator is on its own circuit (to make this simple) and needs 10 amps, and you follow (for instance) Colin's guide and use 10-gauge wire (good for up to 30 amps), then the fuse must be at least 10 amps (so the refrigerator can run without blowing the fuse) but no more than 30 amps (for safety). As long as the refrigerator has its own fuse, you can use up to 30 A for the circuit, but the manual might say something like "must be supplied by a circuit with a fuse of no more than 15A", or something like that.

It doesn't make sense to me to fuse for vastly higher currents than would reasonably be expected, even if the wire could handle it safely, but others may disagree.

Sorry about the [b]terminology confusion: since the thing which is using electricity determines how much current (or power) flows, some of us sometimes refer to that device as "drawing" current; it doesn't mean anything different from the battery "sending" current, or "pushing" current through the device, it's just a different perspective.

In this discussion, we have really only been concerned with [b]protecting the wire - not the battery - because no normal load in a trailer could need enough current to be too much for the battery. A big inverter (for instance) connected by large-gauge wire (think car battery cables...) to a small trailer battery could mean that the battery would be damaged before a fuse blew. Matching components is a good thing...

Darwin Maring 05-09-2006 05:44 PM

Brian is totally correct. Do not over fuse. Use the lowest rated circuit breaker possible for the load regardless of the gauge of wire.

Even though I use 12 gauge wire I often use 15Amp breaker based on the load. Note: I can use a 20 Amp breaker on that gage of wire if I need to.

The smaller Amp breaker is another safety measure.


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