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non-insulated negative wire

John Frum

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Nov 30, 2019
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For low voltage dc why use insulated wire for the negative current carrying conductor?
Insulation reduces the heat dissipation capacity of the conductor.
Going further with this idea I see a lot of van builds are framed with 8020 extruded aluminum.
I wonder if that would make an acceptable return path.

 
The positive wire has to be insulated. Are you planning to pass more amperage on the negative side than the positive side? :)
 
The positive wire has to be insulated. Are you planning to pass more amperage on the negative side than the positive side? :)
Nope but its still better if the wire is cooler.
Or instead of wire a big combined busbar/heatsink such as a piece of structural extruded aluminum.
Fault detection and clearance is enhanced in a chassis return design.
The un-insulated wires would serve the same purpose but to a lesser extent.
 
For low voltage dc why use insulated wire for the negative current carrying conductor?
Insulation reduces the heat dissipation capacity of the conductor.
Going further with this idea I see a lot of van builds are framed with 8020 extruded aluminum.
I wonder if that would make an acceptable return path.


Maybe if you had a suitable bond at each joint of the T-slot.
As a ground conductor there is the WEEB system. probably much lower current than you're thinking of.
More like the effort people go through to get good connections to aluminum cell terminals.
Now if you weld it, should be good enough. Just have to deal with the transition to other conductors.
 
I was thinking that for a van build you would have 1 continuous piece along the drivers side wall from behind the driver's seat to the rear doors.
Most of the vans now have the starter battery under the driver's seat.
The core of the system could be behind the driver's seat.
 
Yes, a ground plane, better named common negative reference, would be fine. If using aluminum the connections must be checked often to avoid corrosion or coming loose. I would recommend a copper bar.
In my steel van I return negatives for small devices using the chassis. I don't trust the chassis for critical or higher ampere devices. The insulation doesn't effect the negative cables as they are sized appropriate to the maximum amperes in the circuit. bare wire would be easier damaged.
 
What was the final verdict here?
Will you be running the same length of negative wire as you are running positive?
Will it be insulated wire or bare?
Where will the negative wire terminate?

And final Question: WHY?
 
What was the final verdict here?
So far its been a thought experiment.
If I ever do a van with aluminum bones I will try to remember to update this thread.
Will you be running the same length of negative wire as you are running positive?
Nope.
Why would I?
Will it be insulated wire or bare?
The majority of the return path would be un-insulated 80/20.
Where will the negative wire terminate?
That is a question of perspective.
The house system return wires will terminate on the house busbar which could be the 80/20 skeleton.
The house busbar will likely also be connected via a wire to the starter battery negative or possibly just bonded to the frame.
And final Question: WHY?
I like the idea of an negative busbar that spans most of the length of the vehicle.
The branch circuit returns could be terminated to the closest bit of aluminum as would all circuits.
 
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If the wire is hot enough to have insulation issues.... the wire is too small.
Using the frame as a return path is fine as long as everything stays clean and tight. The chassis system certainly uses the frame.
 
If you use good earth anchor points, you can use the vehicle body as your earth path.
 
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