I have questions about wiring 12 volt LED light fixtures in fiberglass motorhome

dwh

Tail-End Charlie
What do you guys think about using this fuse block? http://tinyurl.com/kyy75qj or try this if the other link doesn't work http://www.ebay.com/itm/Universal-8...743787?hash=item465e88f1ab:g:saEAAOSw3v5Yr6Qi

Not great. The problem is having to wire a hot to every fuse slot.

Better to have a fusebox where the fuses are all fed from a common bus bar. That way you just run one fat wire from battery to fuse box.

Even better if it also has a negative bus, then you just run a fat +/- pair from battery to fusebox, and run all your branch circuit +/- pairs to the fusebox as well.

Like this:

247244F-p.jpg
 
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magentawave

Adventurer
E) Don't solder. Use crimp-on plugs to connect the fixture wires to the #14 so you can unplug and replace the fixtures when they crap out, without having to monkey with the main wiring.


Thanks for all of your help and diagrams, etc.

Regarding the T...

I understand that I should use crimp butt connections instead of soldering for joining TWO pieces of wire together. However, I still don't understand the best way to connect the point (the T) where the wire from a light connects to the main positive and main negative wire?? I don't see how butt connectors can work at the T. Can you explain that please?

Thanks
 

dlh62c

Explorer
You will use parallel wiring...

wiring-led-lights-in-parallel-l-207978fdbcae2864.jpg



(And will have a fusebox at the end, not a transformer.)

Use parallel wiring.

Make the connections at the lamps using Nylon Quick Disconnect Pairs. Only use butt splices when your wire runs come up short in length.

Tie the nodes together using Blue Sea terminal strips, terminal jumpers and ring terminals. One strip for the positive connections, top row in diagram. one strip for the negative connections, bottom row in diagram.

Make your power and ground connections between the terminal strips and the Blue Sea fuse block.

I prefer inside lights that have their own switches. It simplifies things.
 
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pugslyyy

Expedition Vehicle Engineer Guy
I tend to use a blended approach - crimp on butt connectors with heat shrink for inline connections, and strip/solder/tape for taps. If space is tight it can be a lot easier to get in and strip a wire back a bit and solder another one on without having to cut the first.

I'm not a big fan of the insulation-displacement crimp on taps, I seem to have a tough time getting a reliable connection with them so don't use them any more. I'm not saying that they can't work (because lots of folks use them), just that they didn't for me.

I have a pro-grade ratcheting crimping tool that help me use the right amount of pressure on each connector.

Split loom can be very useful, both for protecting wires and just giving a neat and finished appearance. You can buy 100' lengths of it for cheap
 

IdaSHO

IDACAMPER
I agree about the crimp on taps. I do have a spot for them on the wall, along with the other dozen or so types of small crimp connectors, but they never get used.

Also, I find that with most of the available (cheap) crimp connectors, it is best to pull the insulator off of them and not even use it.

This is especially true with very small wires and crimp connectors.

Pull the insulator off, slip a small bit of heat shrink over the wire, crimp on connector, then heat shrink.
 

dwh

Tail-End Charlie
Rig your #14 runs like this:

crimp_three_ground_finish_annotated.jpg



Using this sort of crimp connector (1/4" insulated spade connector):

41kwOwpd-ZL._SY400_.jpg



But, the insulated spade connectors in that pic above are made to take wire size #22-#16, which would probably be large enough for the wire coming out of the fixtures, but not large enough for the other side where you need it large enough to take a pair of #14s.


You could get 1/4" females rated for wire size #12-#10 (yellow), which should work fine for two #14s:

http://www.parts-express.com/1-4-(1...connect-crimp-terminal-yellow-50-pcs--095-304


And 1/4" males rated #16-#22 (red), which should work fine for the fixtures:

http://www.parts-express.com/1-4-(2...disconnect-crimp-terminal-red-50-pcs--095-310


Easy peasy.
 

dwh

Tail-End Charlie
Using this sort of crimp connector (1/4" insulated spade connector):

41kwOwpd-ZL._SY400_.jpg



But, the insulated spade connectors in that pic above are made to take wire size #22-#16

Woops. My bad. That's what I get for changing the image after I wrote the text. Duh.

What I meant to show with that pic, is that 1/4" spades are interchangeable. I.e., you could have a yellow female and red male and they would still connect together.
 

dwh

Tail-End Charlie
Oh, and to use a yellow rated #12-#10, for a single #14 at the end of the run, just strip twice as much insulation off and fold the wire over to double it.

(Or just use the Armstrong method and squeeze the crimper with both hands. :) )
 

dlh62c

Explorer

If your wire runs are short and though cabinets and cupboards the above will work.

If your wire runs are buried in the ceiling, walls and under the floor, the above is poor practice. Do not splice. Not doing so results in ALL crimp connections being located at the source or at the use-end on the conductors. This simplifies troubleshooting should shorts or opens occur. Its a hard discipline to maintain, when making long runs.

I use duplex wire exclusively in my 12vdc system and use triplex wire for my AC system. I use single wire for control signals.

When you use the Nylon Insulated Disconnects you use one sex for the positive and its mate for the negative. This prevents someone from switching the wires when connecting things up.

I use Ancor Wire. Its a pleasure to work with.

Ancor Triplex Wire for AC power.
Ancor Nylon Insulated Disconnects
Blue Sea Terminal Block
Blue Sea Terminal Block Jumpers

Take pride in your work!
 
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dwh

Tail-End Charlie
Do not splice. Not doing so results in ALL crimp connections being located at the source or at the use-end on the conductors.

Doing it the way shown in the pic ALSO "results in ALL crimp connections being located at the source or at the use-end on the conductors".

All the crimps will either be at the fuse box or at the fixtures.

It's not like he's going to be using a spade connector to crimp two pieces of wire together buried somewhere in a wall 3' from any fixtures.
 

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