Outside (on roof rack) 12VDC power bus?

[Pskhaat]

Folks, running 12VDC with ~40A capacity up to the roof rack, there will the "obligatory" LED lighting as well as outlets for the rooftent and an eventual solar feed. I'd like to terminate a bus/breakout from somewhere such that I'm not splicing/tapping every time. What solutions have you used for this?

Another question, anyone else used the rack itself (aluminum here) as a common ground and simplifying wiring?

 

[rayra]

I would think you are going to want some sort of weatherproof enclosure / junction box up top, with your fuse / distribution up in it. Would simplify your wiring routings and your rooftop solar can connect there and you have just one power line running into the vehicle to your battery(ies).

I've seen hobby electronics enclosures used and also things like pelican / apache cases, IIRC they are IP7 and 6 rated, respectively. Grommets or bulkhead fittings thru the side wall of the case. See HAM radio forums for 'field' boxes for lots of useful ideas / details

Wiring depends also on how much you are trying to hide the wiring.

I would not make the rack a common ground, you're essentially electrifying your rack (or making it a path for stray voltage) and making anything else that touches it (including people) a potential grounding path. You're running one wire for power anyway, what does it matter to run two?

 

[Pskhaat]

Wiring depends also on how much you are trying to hide the wiring. ... You're running one wire for power anyway, what does it matter to run two?

Hiding will be done but I'm more into function than form. That said, the wiring is actually going up the side of the windshield. I am seriously debating 105°C 8/2UFB wire wrapped in a poly sleeve, so yes I would run ground up.

I would not make the rack a common ground, you're essentially electrifying your rack (or making it a path for stray voltage) and making anything else that touches it (including people) a potential grounding path.

Yes, but, it is only 12V and certainly not enough potential to arc through human contact. That said, so is the body of the vehicle a common ground. I do have dissimilar metals though.

 

[Rando]

These would make a nice professional solution:
http://www.connectorconcepts.com/stsesevec.html, more details: http://www.prolecproducts.com.au/catalog/a124.pdf

 

[Alloy]

How will you switch things?

I've never had a waterproof enclosure that is corrosion/condensation proof so I make individual runs with 2 conductor tinned wire. Outside jacket on the wire will provide better protection

An enclosure that has to be opened in the rain/snow to access wires/switches/fuses is no longer waterproof

A common ground on the rack wouldn't hurt anything

 

[Pskhaat]

These would make a nice professional solution:
http://www.connectorconcepts.com/stsesevec.html, more details: http://www.prolecproducts.com.au/catalog/a124.pdf

Fascinating. I am reading more on this. This is effectively of what I was thinking. Price is high, BUT start adding up time, connectors, solder, relays, etc etc falls right in there.

 

[Pskhaat]

How will you switch things?

In the 8/2ufb there is a smaller ground wire which I would use to assert the relay for the LED lights (I'm embarrassed to say I even have them!). Otherwise, everything else planned up there is all switched up there. The only in-cab switch is the lighting.

Outside jacket on the wire will provide better protection

And that's why I'm thinking about using UF-B. (and I'll wrap it (again) with the poly sleeve)

 

[Rando]

I am not sure solid core wire would be a great idea for this application. There is plenty of UV stabilized stranded/tinned wire available. If you want a hardware store solution, look at low voltage landscape wire - duplex, UV stabilized and stranded.

 

[Pskhaat]

If you want a hardware store solution, look at low voltage landscape wire - duplex, UV stabilized and stranded.

It's not so much "hardware store" stuff, it is that it is flat, rated, and can both run underneath the lower windshield fairing and fits almost perfectly between the glass and A-pillar, it also has a "ground" wire that I can employ to assert the lighting relay. I'm absolutely open to all other suggestions. Isn't almost all low voltage (albeit with the same 105°C cap) all just 2 wires?

 

[john61ct]

For waterproof connectors I like TE Deutsch DTP not sure max ampacity per pin.

The junction boxen would need to be very robust and UV resistant.

Stranded tinned UL-rated "boat cable" afaic and milspectested proper crimping, adhesive-lined heatshrink.

No to the rack being live as common, nor relying on any chassis for negative return at those currents, as vehicle body rusts puts a variable in there IMO.

 

[Alloy]

.

In the 8/2ufb there is a smaller ground wire which I would use to assert the relay for the LED lights (I'm embarrassed to say I even have them!). Otherwise, everything else planned up there is all switched up there. The only in-cab switch is the lighting.

And that's why I'm thinking about using UF-B. (and I'll wrap it (again) with the poly sleeve)

DC equipment uses a different connection system that makes the use of solid wire more difficult......something to look at beforehand.

 

[Pskhaat]

DC equipment uses a different connection system that makes the use of solid wire more difficult.

?. That specific wire is stranded and why I was considering it. ? ...but reconsidering too.

 

[Rando]

You can also get almost the same thing in fine stranded, tinned wire, in a variety of gauges:

Amazon.com : Ancor Marine Grade Duplex and Triplex Wire : Sports & Outdoors

Amazon.com : Ancor Marine Grade Duplex and Triplex Wire : Sports & Outdoors

www.amazon.com

However, if you are considering running a relay box up there, it may be wise to run several more control wires to be future proof. Maybe a duplex power lead and then a multi-conductor control cable:

30-01283 Tensility International Corp | Cables, Wires | DigiKey

Order today, ships today. 30-01283 – 5 Conductor Multi-Conductor Cable Black 26 AWG 16.40' (5.00m) from Tensility International Corp. Pricing and Availability on millions of electronic components from Digi-Key Electronics.

www.digikey.com

 

[VanWaLife]

I've had good success in the truck and the boat using plastic liquid tight enclosures and liquid tight conduit from home depot to route power around. You could run some liquid tight conduit to a liquid tight box on the rack, then install whatever type power outlets you want in the box to get power from the box to your devices. I've also used plastic plano ammo boxes for switches, etc. I'd avoid using an aluminum rack to ground, my guess is that will cause either the rack or the wires to corrode.

 

[Alloy]

?. That specific wire is stranded and why I was considering it. ? ...but reconsidering too.

I thought you were going to use smaller (like 14ga that is solid) UF-B on the rack for distrubution wiring.