Someone with some knowledge please help. I have someone trying to help me who knows a ton, but doesn't know how to teach worth a crap.

I'm wiring my little Toyota RV. I have 4 LED lights, a little water pump, and maybe one or two other things. I'm wiring them into a power converter/power center.

I bought 12 gauge wire for the electronics. 10 gauge for the battery-to-power center wire. I figured thicker gauge would cover my bases better.

But a concern I'm hearing is that, say with the lights: They have a very low amp draw, being little lights, and LEDs. The point of a fuse is to blow in the event of a surge, before the wire can melt.

I match the fuse to the wire thickness. So with 12 gauge wire maybe a 30amp fuse? Well...with LEDs drawing 2 or 3 amps, a surge could fry them, but not harm the fuse or wire at all, right? Or wrong?

Basically, by using a thick wire, and the appropriate fuse for that wire, am I risking frying my light in the event of a surge? With a smaller fuse and wire, the fuse would blow. But since the fuse may not blow, the light could fry, and even catch fire.

True?

Basically, is it just as dangerous to use too thick a wire gauge as to use too thin? Just for different reasons (wire frying instead of appliance)?

I really don't know much and I want to get this converter wired.

 

Wiring basics 14AWG is rated at 15A max at 120V, 12AWG is 20A at 120V, 10AWG is 30A at 120V...
The fuse/circuit breaker is there to protect the wire from overheating melting and catching fire. A fuse works by melting before the wire gets hot enough to catch fire but because it takes time to heat up and break they are slower to react and not very good at protecting from minor surges/spikes, a big surge/short will break them quickly however.
A CB reacts faster and can protect against smaller surges/spikes this is one of the reasons why bldgs. generally use CB electrical panels today instead of fuse panels.

Never really dangerous to run a larger wire. It can actually be better since the resistance of the larger wire is lower the voltage transmission is more efficient. The larger wires weigh more and are harder to flex/bend into tight spaces however this is one reason why auto makers try to use the smallest wire they can for a given purpose.

As for the fuse size selection you match the fuse to the load you are trying to protect up to the max. allowable for that size of wire.

10AWG from the Batt. to the fuse block (power ctr.) is a good choice provided the total load in the block does not exceed 30A... 8AWG might be a better choice here. If you start running all the lights, the pump and say a 12V microwave/cooler or some other appliance like that you may hit 30A pretty fast. Bigger is always better in this case and it will save you trouble later once you get the interior all together.
For the "house" wiring 12AWG is plenty big enough, on the LEDs even 14AWG would be big enough and easier to solder/connect to them.
As for protecting them from surges/spikes... you can use a smaller fuse that might help but generally they are pretty solid state and can handle a minor spike or two {probably}. If you get zorched hard enough frying them will be the least of your worries.
hope this helps a bit
BTW what kind of spikes are you concerned about?

 

Thaaaaank you. I was starting to think that matching fuses to wire size wasn't a set-in-stone rule, and I could match the fuse to the appliance and not the wire. Great.

Spikes...no idea! I'm on a Toyota Chinook list serve/user group and a Toyota Motorhome forum, and I'm just going by advice people are giving me. I guess it would be more if I was plugged into shore power/120V that would surge/spike, rather than the 12V system spiking. (?)

Thank you very much. Now I just need to figure out exactly how everything hooks into the converter and I'll be all set! It's definitely a steep learning curve for me right now...

It's hard to get "basic" electrical system information! People can't seem to respond without taking things to a way more complicated level and almost immediately lose me, so I've had trouble just getting a basic understanding of how my RV electronics work, and building from there, to where I can feel comfortable wiring connections myself.

 

Yeah that would be more of a shore power thing they are talking about... camp ground/RV parks are notoriously "dirty" when it comes to power brown outs and spikes mainly because of the rural areas and all the different types of systems that might be connected from tents with a radio/light to full on bus size RVs with built in washer/dryers and 55" flat panel entertainment systems... also all the farms sharing the grid and lightning strikes etc...
It can all lead to a very spike-y power feed...
Are you going to have a 120V panel/lights and plugs as well as the 12V or are you going all 12V?

 

Both. I got a Progressive Dynamics Mighty Mini 4045 Power Center/Converter.

I had an electrician wire the 120V side, though.

 

Just took a look at that converter... looks like it is built to handle most minor input fluctuations.

 

Great. Yeah, another Chinook owner suggested it as an upgrade so I bought it. I'm slowly finding out that it was a very good suggestion, and it's a pretty damn good little unit!

 

Hi , can anyone tell me where the clutch start switch connector on a '93 3.0 4wd P/U plugs in to??

 

Seriously?

Start your own thread.

 

It plugs into the back of the clutch start switch. :wabbit2: