DC Wiring Question(s)

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DC Wiring Question(s)

Postby DestinDave » Mon Oct 09, 2017 7:26 pm

Hi, everyone..

Starting on my DC wiring and have a question or two..
I will have the usual devices installed - roof vent fan, radio/stereo, lights ( ceiling, reading, outside, indirect, galley - all LEDs)..
The deep-cycle battery will be connected with a 6 gauge copper wire, via master on/off switch, master fuse, to a 100Amp (max total) 10-way fuse block.
The highest draw will be the vent fan (13 amps), stereo (10 amps), TV/DVD (5 amps), and LED lights (minimal draw). I am using 16 and 18 gauge wire for all individual circuits.

Main question - does the ground wire from the ground bar back to the battery need to be the same gauge as the positive wire (6 gauge)?
I have seen schematics where all devices are grounded to a bus bar then back to the battery but then the battery is also grounded to the trailer frame. Is that even necessary?
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Re: DC Wiring Question(s)

Postby friz » Mon Oct 09, 2017 8:52 pm

DestinDave wrote:Hi, everyone..

Starting on my DC wiring and have a question or two..
I will have the usual devices installed - roof vent fan, radio/stereo, lights ( ceiling, reading, outside, indirect, galley - all LEDs)..
The deep-cycle battery will be connected with a 6 gauge copper wire, via master on/off switch, master fuse, to a 100Amp (max total) 10-way fuse block.
The highest draw will be the vent fan (13 amps), stereo (10 amps), TV/DVD (5 amps), and LED lights (minimal draw). I am using 16 and 18 gauge wire for all individual circuits.

Main question - does the ground wire from the ground bar back to the battery need to be the same gauge as the positive wire (6 gauge)?
I have seen schematics where all devices are grounded to a bus bar then back to the battery but then the battery is also grounded to the trailer frame. Is that even necessary?
Yes the return path for the circuit needs to have the same capacity. No it is not necessary to ground the battery to the frame if it not being used as part of the circuit.

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Re: DC Wiring Question(s)

Postby friz » Mon Oct 09, 2017 8:57 pm

DestinDave wrote:Hi, everyone..

Starting on my DC wiring and have a question or two..
I will have the usual devices installed - roof vent fan, radio/stereo, lights ( ceiling, reading, outside, indirect, galley - all LEDs)..
The deep-cycle battery will be connected with a 6 gauge copper wire, via master on/off switch, master fuse, to a 100Amp (max total) 10-way fuse block.
The highest draw will be the vent fan (13 amps), stereo (10 amps), TV/DVD (5 amps), and LED lights (minimal draw). I am using 16 and 18 gauge wire for all individual circuits.

Main question - does the ground wire from the ground bar back to the battery need to be the same gauge as the positive wire (6 gauge)?
I have seen schematics where all devices are grounded to a bus bar then back to the battery but then the battery is also grounded to the trailer frame. Is that even necessary?
BTW that amp draw seems high for the fan. Mine tops out around 3 amps. If it is 13 amps a 16 g wire seems under sized. You might want to check the charts on this stuff.

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Re: DC Wiring Question(s)

Postby capnTelescope » Mon Oct 09, 2017 9:28 pm

Yes, same size ground wire for ground return.

Automotive best practices would call for a separate ground for each device. They still build 'em as cheap as they can, and that's how they do it. Of course, a car has a lot more opportunities for creating ground loops. But you won't be chasing down why this light is dim and the other bright. Bring all the grounds to a common point or terminal block, and connect that to the battery minus.

Do all your switching on the positive side, or you'll be wondering why your porch lites come on with the TV headlights. Voice of experience.
I'll burn that bridge when I come to it.

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Re: DC Wiring Question(s)

Postby DestinDave » Tue Oct 10, 2017 4:02 pm

friz wrote: BTW that amp draw seems high for the fan. Mine tops out around 3 amps. If it is 13 amps a 16 g wire seems under sized. You might want to check the charts on this stuff.

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:oops: You are correct. I based that on a user's review on Amazon without looking at the owner's manual, my bad. 16g wire will suffice.
Thanks!
Reality? What a concept!
Building "The Salty Tear" - a photo log of the project.
http://www.bluezenphoto.com/p979644357
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Re: DC Wiring Question(s)

Postby DestinDave » Tue Oct 10, 2017 4:05 pm

capnTelescope wrote:Yes, same size ground wire for ground return.

Automotive best practices would call for a separate ground for each device. They still build 'em as cheap as they can, and that's how they do it. Of course, a car has a lot more opportunities for creating ground loops. But you won't be chasing down why this light is dim and the other bright. Bring all the grounds to a common point or terminal block, and connect that to the battery minus.

Do all your switching on the positive side, or you'll be wondering why your porch lites come on with the TV headlights. Voice of experience.

That's the plan... I've had plenty of those "voices" in my lifetime. :lol:
Thanks!
Reality? What a concept!
Building "The Salty Tear" - a photo log of the project.
http://www.bluezenphoto.com/p979644357
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