Approaches to adding 12 volt wire splices

[RogerDat]

I have two tasks requiring additional 12 volt house wires. I want to add a 12 volt outlet (cigarette style plug) at end of kitchen counter and I want to run a line up to roof vent so I can install a powered Fantastic Fan.

My inclination is to use taped wire nuts or crimp closed end connectors and shrink tube if there is enough slack. Probably 12 gauge wire for outlet, will connect to main run under sink. 14 awg for the power vent, will connect to light fixture in overhead cupboard

I didn't ask what is the "best" way because that ends up as an argument. More than one way that gets this cat skinned, I'm seeking ideas, not a cage match to the death between Electrical Engineers, Electricians, and the old guy who has done it this way for years.

[Raz]

I'm not quite sure what you are asking but since what you wish to power, a fan and outlets most likely require less than 5 amps each, the size wire you use is less important there than the size you connect to as that will be carrying the additional current. When I added power outlets for charging, I ran right to the converter and fused accordingly.

[steve dunham]

Originally Posted by Raz

I'm not quite sure what you are asking but since what you wish to power, a fan and outlets most likely require less than 5 amps each, the size wire you use is less important there than the size you connect to as that will be carrying the additional current. When I added power outlets for charging, I ran right to the converter and fused accordingly.

Kind of the the same thinking . When I added a 12 VDC receptacle , I ran a pair of #12 stranded conductors (1 red , 1 Blk ) from the converter to the receptacle. Like Raz , I thought it was best not to tap into a conductor that may be already heavily loaded .

[gordon2]

Vote #3 for a new circuit.... I don't know about your older Scamp. Mine has a power distribution center that had a few empty slots for additional 12 VDC circuits so I used one of those. This way I knew I had proper fuse and wiring from the panel and was not adding to a an unknown circuit that might already be close to maxed out on it's fuse. If I recall right, the TOTAL for the 12 VDC from the panel was still restricted to 20 amps.

As for the 12 volt outlet. Look at what the outlet is rated at also. Again, without looking and if I recall right, mine was good for 10 amps so that is what I planned for. Note that a Scamp Facebook group right now is talking about a 12 volt cooker that plugs into a cigarette lighter plug and draws around 12 amps when heating up and 8 amps while cooking. Some of those folks are going to have blown fuses, or melted hardware (or worse)!

[RogerDat]

No converter just a single wht/blk pair of wires running under sink. The only 12 volt draws are two lights on ends of top cabinets over stove/sink. Now replaced with LED. That line has a barrel fuse holder.


On the way to the sink the line also feeds the 3 way fridge. Which I think also has a barrel fuse. Don't run the fridge on 12 volt.

Didn't even come with a battery holder or hookup. I added a pig tail junction and ran a pair of 10 awg wire to go to battery to feed the house wht/blk pair. The connection to the charging line from tow vehicle is also made here. I think originally only had 12 volt lights from the tow vehicle.

I guess I could add in a junction box just for house wiring and move the house power connections all to it with a single jumper line going back to the pig tail junction box to tie into battery and charging circuit. Not really enough room to run multiple pairs of +/- lines to that same junction. I'm already using a short connector wire to a wire nut because I couldn't get all the ground wires on the posts in that pig tail junction box.

I don't think the fantastic fan and 2 led lights will draw too much for that branch line since originally it would have been 2 incandescent bulbs. And I can pick that line up at the light fixture for the short hop to the fan.

The 12 volt outlet I only intend to use for charging phone BUT it could be used for fan or even a coffee pot so maybe it demands a line of it's own.

[RogerDat]

PS. I did run 10 awg and separate ground for the trailer brakes.

[Byron Kinnaman]

Originally Posted by RogerDat

I have two tasks requiring additional 12 volt house wires. I want to add a 12 volt outlet (cigarette style plug) at end of kitchen counter and I want to run a line up to roof vent so I can install a powered Fantastic Fan.

My inclination is to use taped wire nuts or crimp closed end connectors and shrink tube if there is enough slack. Probably 12 gauge wire for outlet, will connect to main run under sink. 14 awg for the power vent, will connect to light fixture in overhead cupboard

I didn't ask what is the "best" way because that ends up as an argument. More than one way that gets this cat skinned, I'm seeking ideas, not a cage match to the death between Electrical Engineers, Electricians, and the old guy who has done it this way for years.

When it comes to wire the type of insulation is more important than wire size. Vinyl will sustain fire it should not be used. Use automotive wire with "cross link"(teflon) insulation.

[gordon2]

Originally Posted by RogerDat

No converter just a single wht/blk pair of wires running under sink. ..
... so maybe it demands a line of it's own.

Without seeing it in person, I can't say what I would do, but it sounds like just running a separate line straight from the battery, and fused at the battery, might be a good way to do it. And it is a good point to use proper gauge and insulation.

[stevebaz]

To answer your question if I were splicing wires I would either use butt connectors with shrink insulation attached or I would use plain old butt connectors and the marine adhesive lined shrink tubing from harbor freight. Use a good pair of heavy duty plier type crimpers.

With a 12 volt outlet I would oversize the wires and run both positive and negative and have it on its own circuit and fuse. There are allot of heavy draw items that can be plugged into those sockets from heaters to coffee pots and electric blankets. Even if you use smaller wire and limit it with a smaller fuse doesn't mean someone else later wont install a larger fuse and put themselves and the trailer in danger.

With the fan you can run proper wire and properly fused installation because its wired in as a appliance and no one will be hooking up different things in your wire run.

https://www.pepboys.com/product/details/431396/00841

https://www.pepboys.com/product/details/8353894/00841

https://www.harborfreight.com/42-pie...ing-67598.html

https://www.pepboys.com/product/details/9889639/00841

[RogerDat]

Originally Posted by gordon2

Without seeing it in person, I can't say what I would do, but it sounds like just running a separate line straight from the battery, and fused at the battery, might be a good way to do it. And it is a good point to use proper gauge and insulation.

You know that may be the best way to deal with that outlet. Just run wire all the way to battery.

I probably wouldn't but someone might even plug a small inverter into that 12 volt outlet. If nothing else make the fuse easier to find :-) especially if blowing the fuse didn't knock out the lights because not on same circuit.

I'll do a double check on the fuse for the line to the lights but a fantastic fan is well under 5 amps, add two 1157 style LED bulbs or even incandescent bulbs from auto parts store and still cover 15 amp draw if that is 14 awg. Not sure what the heating element of fridge draws but don't think I would ever use it and can check. That part of the line I think is 12 awg.

I'll have to check but think I have some 10 awg wire I can use for the outlet or could just use 12 what did other folks use?

Converter lost out on my wish list to solar. I figure I can pack a small battery charger if I need to charge from shore power.

[Raz]

If my converter died today I would replace it with a distribution box with a main fuse and fused branches. Bear in mind there is a lot of energy stored in your battery.

[wbullivant]

As others have said, first determine how much load the circuit will carry and go back to the fuse box or battery if necessary. If however, you do decide to splice into an existing wire you do want to make a joint which will not cause problems latter. My choice for a 'bulletproof' splice is to twist the copper conductors together then solder with rosin core electrical solder. Cover with heat shrink tubing or quality electrical tape. Done correctly this will be a lifetime splice. Crimp connectors have their place for components which may need to be later disconnected, but they are inherently somewhat unreliable.

[Darwin Maring]

Crimp Connector and only crimp once. If you attempt to crimp a second time, you mess up the first crimp. This is according to Military Specifications.

I use one of these and it insures a perfect crimp every time.
https://www.harborfreight.com/ratche...ool-97420.html

[Radar1]

You mentioned possibly a coffee pot. They can use 13 amps/156 watts so you'll want to make sure the entire circuit is wired and fused correctly for that, as well as the DC plug. We ran a heavy wire from our solar charge controller load connection to a new junction box where we can run separate lines in the future.