Wiring advice needed

Hello all!

Currently, the only thing I am powering from the bed is my ARB fridge which is listed as 10ga wiring. ARB states the fridge consumes .89amps/hr on average. In the next week I will be adding a diesel heater to the arsenal to run during the cold nights which appear to draw around 1amp/hour once running per online forums. I am wanting to do some consolidation and run a fuse block to the bed of the truck so I can run plugs for the fridge and heater, as well as one of the Amazon outlet panels. I have seen people run anywhere from 4ga to 10ga wire from the battery to their fuse panel in the bed, and I have seen some run an inline fuse on that wire, and some wire a 100amp breaker close to the battery. I guess I am looking for advice to see if I can get away with the 10ga wires already being used for my ARB fridge to power the fuse block, or if I should run a larger size, and if I should put a fuse in-line or run a breaker. Thanks for the help in advance!

 

If those are the only two devices you’ll be running or maybe a few small LED’s added on, 10awg will be fine (actual 10awg OFC, not cheap crap like boss CCA)

 

This if from Blue Sea so it's intended for 12v DC wiring good rule of thumb here. It illustrates the importance of wire guage and gauge for the length of the circuit run.

Also it's a great idea to have a fuse or breaker within 12" of the battery so a dead short from chaffing or such doesn't burn your truck down.

 

...and another wire size calculator.

https://www.wirebarn.com/Wire-Calculator-_ep_41.html

 

Size the breaker to the load. You will likely never get anywhere close to 100 amps. There is no point in having it there (other than looks I guess) if it is too big to trip in the event of an overload.

 

Ok

first off consumption over a period of time is useless for wire sizing. You need to know peak amperage draw, being a fridge or condensing unit you’re going to have inrush when the cooling cycle starts so you’re sizing for 3-7 times the running amperage. Some light digging shows that the ARB fridges are around 60-100watts running. So that’s 5-8amps X inrush your #10 being able to handle 30-35amps continually this wire is sized appropriate. Adding something like a 100w block heater to the system is not out of the question because that is a constant 100w consumption. #8 or 6 would be better for in rush capacity.

That’s my $.02

 

Yeah you don’t want a breaker that will allow more power than the wire can handle.

10awg wire is good for about 30A, so your fuse/breaker needs to be no more than 30A. The fuse is made to be the weak link. In the event of a short, you want the fuse to blow instead of the wire catching on fire.

 

OP, make a list of anything and everything you may want to run off this new fuse panel in the bed. Figure up the amp draw of each item, remember inrush or startup current as mentioned above. Total up the amperage load and add 20% to give yourself a cushion (so 6 amps for a 30 amp total for example). Use the chart posted above to size the wire accordingly and again, size the breaker to the load/wire. There is such a thing as oversized in the world of electricity.

 

Remember to consider diversity factory when sizing the main breaker to your panel, from there size out individual fused loads and wire size as mentioned above.