grounding the cabin battery

[mariannf]

Hi all,

I am working on my first build, and have a Dc/12 volt system electrical question: I will have battery in the tongue box or possibly under the floor. How do i ground it? What is the connection point and how do i make it?
thank you?

[Dale M.]

Typically you supply a ground bar (-) along with the 12 volt DC (+) buss bar (fuse panel) for connecting electrical loads... To ground to chassis (frame) you can just use one connection point on ground bar and run a wire off ground bar directly to a convenient point on frame(chassis) ... Typically at frame you would drill hole for bolt or screw, clean metal to bright shiny surface and crimp a connector (terminal) on cable and then secure connector to frame using a dab of dielectric grease to prevent corrosion.... Other method my be to take ground wire directly off negative (-) connector of battery directly to chassis...

It's not rocket science, its just providing a electrical bath from negative (-) side of battery to frame of TD...

In many cases if you do proper wiring from electrical device to fuse/ground panel it may not even be necessary to ground chassis... That being said there are safety issues and if you have one wire electrical (light) circuits (grounded at frame body at device) and charge by towing and 120 V AC circuitry in trailer it may be prudent to have proper frame chassis ground on DC circuits also...

Dale

[mariannf]

Typically you supply a ground bar (-) along with the 12 volt DC (+) buss bar (fuse panel) for connecting electrical loads... To ground to chassis (frame) you can just use one connection point on ground bar and run a wire off ground bar directly to a convenient point on frame(chassis) ... Typically at frame you would drill hole for bolt or screw, clean metal to bright shiny surface and crimp a connector (terminal) on cable and then secure connector to frame using a dab of dielectric grease to prevent corrosion.... Other method my be to take ground wire directly off negative (-) connector of battery directly to chassis...

It's not rocket science, its just providing a electrical bath from negative (-) side of battery to frame of TD...

In many cases if you do proper wiring from electrical device to fuse/ground panel it may not even be necessary to ground chassis... That being said there are safety issues and if you have one wire electrical (light) circuits (grounded at frame body at device) and charge by towing and 120 V AC circuitry in trailer it may be prudent to have proper frame chassis ground on DC circuits also...

Dale

Thanks so much Dale! do you have picture examples that you can share.
I want to make sure I have this right: have ground bar and buss bar. battery gets connected to both (negative to ground bar, positive to buss bar). Run a wire from the ground bar (negative) to the frame (assuring that the point on the frame is scraped down to metal).connect the wore to the frame using a bolt.
If this is right i have a question: what kind of wire should I use from the ground bar tot he frame?

Many thanks!

[dmdc411]

I kept a copy of this pic from right here.

uploadfromtaptalk1457664919073.jpg (84.14 KiB) Viewed 4928 times

[Dale M.]

As for wire , just a length of good quality stranded wire may be 12 or 10 gauge... Its not a high current load wire its just mainly a "bond" between battery and chassis...

Dale

[S. Heisley]

Mariann, it is my personal opinion that the way/the plans you decide upon for your electrical system can change how you do nearly everything. You can do a simple Caseydog style electrical and/or a battery or you can go with a full-blown electrical with a controller and a battery. You can also decide to charge your battery via the tow vehicle and/or solar or a simple battery charger.

The electrical threads, here on the forum, seem to sometimes spark controversy. If you look, you can find threads where arguments have broken out about how to ground your battery or if you even should. Everyone seems to have an opinion and they don't necessarily agree with everyone else. Just speaking out, as I am now, may lead to someone disagreeing. Many people are "experts" in their way a doing the wiring because it has worked for them (me included), for their system. However, their way may not be the same as your way. Because of this, you may not get as many answers as you would like unless you put more time into explaining your plan, just like you did with your drawing of your cabin.

If you are going to use a controller, the installation instructions will most likely tell you not only how to ground your battery; but also, what size wires to use for both grounding and for battery to controller, etc. My controller installation instructions stipulated that I should use 8 gauge wire for both of those, which I complied with. What size wires you use for your lights and outlets will depend on both their size, usage, distance, even how many of each you plan to put per wire run. In most instances 12 gauge stranded wire will be sufficient; but, not always. 12 gauge is what is used in most standard extension cords and you know there are cautions with those.

Now that I have the above out of the way, I will say, Yes, ground your battery to your trailer frame. You can get special grounding screws to use at most hardware stores. I've read where sometimes those screws come loose; so, once you know that everything is working correctly, you may want to put a little spray paint or some black weather caulking around that spot (with the screw already in position) to help hold it. Now, how this works is that, when you trailer is attached to the tow vehicle, your tow vehicle provides the ground. When you are at camp, you can drop one of you trailer chains to the ground to help provide "grounding insurance", although, it is my opinion that the jack(s) and stabilizers provide some grounding as well.

While you don't have to, you may want to get a good paperback on 12 volt electrical so you can find your own hows and whys. One that I found to be among the best was Managing 12 Volts, How to upgrade, operate and Troubleshoot 12 Volt Electrical Systems by Harold Barre. It is fairly small and reasonably easy reading ( although, I'd be fibbing if I didn't tell you that I fell asleep a couple times while reading). May I also say that I have come to respect the electrical answers being given by our currently active members, MtnDon and bdosborn, not only for their knowledge but also for their simple, down-to-earth way of explaining things. While many don't appear to be posting much anymore, there are others as well; but, those two stick out in my mind. Not wanting to disrespect anyone, there are some other active members who may also be good.

Sorry...It looks like I've written another "book".

PS. Caseydog's super simple way: viewtopic.php?f=30&t=37732

[Graniterich]

Why ground at all? Dual wire house system to fuse panel two wires to each device.

[S. Heisley]

Why ground at all? Dual wire house system to fuse panel two wires to each device.

The electrical threads, here on the forum, seem to sometimes spark controversy. If you look, you can find threads where arguments have broken out about how to ground your battery or if you even should. Everyone seems to have an opinion and they don't necessarily agree with everyone else. Just speaking out, as I am now, may lead to someone disagreeing.

...Point made. Thank you.

[H.A.]

[?

[mariannf]

Thank you all!

Sharon Yes, I am seeing as I go through various threads there are a lot of ways of going about this.

Why ground at all? Dual wire house system to fuse panel two wires to each device.

Granite rich what do you mean by dual wire house system?
I have seen some examples of the battery negative going right to the ground bar. Is this what you refer to?

[Dale M.]

Mariann, it is my personal opinion that the way/the plans you decide upon for your electrical system can change how you do nearly everything. You can do a simple Caseydog style electrical and/or a battery or you can go with a full-blown electrical with a controller and a battery. You can also decide to charge your battery via the tow vehicle and/or solar or a simple battery charger.

The electrical threads, here on the forum, seem to sometimes spark controversy. If you look, you can find threads where arguments have broken out about how to ground your battery or if you even should. Everyone seems to have an opinion and they don't necessarily agree with everyone else. Just speaking out, as I am now, may lead to someone disagreeing. Many people are "experts" in their way a doing the wiring because it has worked for them (me included), for their system. However, their way may not be the same as your way. Because of this, you may not get as many answers as you would like unless you put more time into explaining your plan, just like you did with your drawing of your cabin.

If you are going to use a controller, the installation instructions will most likely tell you not only how to ground your battery; but also, what size wires to use for both grounding and for battery to controller, etc. My controller installation instructions stipulated that I should use 8 gauge wire for both of those, which I complied with. What size wires you use for your lights and outlets will depend on both their size, usage, distance, even how many of each you plan to put per wire run. In most instances 12 gauge stranded wire will be sufficient; but, not always. 12 gauge is what is used in most standard extension cords and you know there are cautions with those.

Now that I have the above out of the way, I will say, Yes, ground your battery to your trailer frame. You can get special grounding screws to use at most hardware stores. I've read where sometimes those screws come loose; so, once you know that everything is working correctly, you may want to put a little spray paint or some black weather caulking around that spot (with the screw already in position) to help hold it. Now, how this works is that, when you trailer is attached to the tow vehicle, your tow vehicle provides the ground. When you are at camp, you can drop one of you trailer chains to the ground to help provide "grounding insurance", although, it is my opinion that the jack(s) and stabilizers provide some grounding as well.

While you don't have to, you may want to get a good paperback on 12 volt electrical so you can find your own hows and whys. One that I found to be among the best was Managing 12 Volts, How to upgrade, operate and Troubleshoot 12 Volt Electrical Systems by Harold Barre. It is fairly small and reasonably easy reading ( although, I'd be fibbing if I didn't tell you that I fell asleep a couple times while reading). May I also say that I have come to respect the electrical answers being given by our currently active members, MtnDon and bdosborn, not only for their knowledge but also for their simple, down-to-earth way of explaining things. While many don't appear to be posting much anymore, there are others as well; but, those two stick out in my mind. Not wanting to disrespect anyone, there are some other active members who may also be good.

Sorry...It looks like I've written another "book".

PS. Caseydog's super simple way: viewtopic.php?f=30&t=37732

Clarification here... The ground from the tow vehicle provides is only for lighting and circuits powered by tow vehicle... Has no effect on cabin power circuits supplied by trailer battery... Except possible charging trailer battery while towing...

Dale

[Graniterich]

Thank you all!

Sharon Yes, I am seeing as I go through various threads there are a lot of ways of going about this.

Why ground at all? Dual wire house system to fuse panel two wires to each device.

Granite rich what do you mean by dual wire house system?
I have seen some examples of the battery negative going right to the ground bar. Is this what you refer to?

I meant two wires from ground / fuse box to each light, fan, and any other load.

[mariannf]

Thank you all!

Sharon Yes, I am seeing as I go through various threads there are a lot of ways of going about this.

Why ground at all? Dual wire house system to fuse panel two wires to each device.

Granite rich what do you mean by dual wire house system?
I have seen some examples of the battery negative going right to the ground bar. Is this what you refer to?

I meant two wires from ground / fuse box to each light, fan, and any other load.

Ok, I was planning on doing this. tell me if I got it right: one wire from each item (fan, etc...) to the fuse bar, and one wire from each item to the ground bar. likewise that battery has one wire to the fuse box and one wire to the ground bar. if this is right then no need to ground the battery to the frame?
why not? thank again!

[PaulC]

Thank you all!

Sharon Yes, I am seeing as I go through various threads there are a lot of ways of going about this.

Why ground at all? Dual wire house system to fuse panel two wires to each device.

Granite rich what do you mean by dual wire house system?
I have seen some examples of the battery negative going right to the ground bar. Is this what you refer to?

I meant two wires from ground / fuse box to each light, fan, and any other load.

Ok, I was planning on doing this. tell me if I got it right: one wire from each item (fan, etc...) to the fuse bar, and one wire from each item to the ground bar. likewise that battery has one wire to the fuse box and one wire to the ground bar. if this is right then no need to ground the battery to the frame?
why not? thank again!

That's right Mariann. Just like a torch. Simplicity itself.
Cheers
Paul

[mariannf]

Thank you all!

Sharon Yes, I am seeing as I go through various threads there are a lot of ways of going about this.

Why ground at all? Dual wire house system to fuse panel two wires to each device.

Granite rich what do you mean by dual wire house system?
I have seen some examples of the battery negative going right to the ground bar. Is this what you refer to?

I meant two wires from ground / fuse box to each light, fan, and any other load.

Ok, I was planning on doing this. tell me if I got it right: one wire from each item (fan, etc...) to the fuse bar, and one wire from each item to the ground bar. likewise that battery has one wire to the fuse box and one wire to the ground bar. if this is right then no need to ground the battery to the frame?
why not? thank again!

Hi Paul I just want to make sure your reference to a "torch" was meant to say that what I described was simple and right and not used to say if I do it this way I'll set everything on fire!
That's right Mariann. Just like a torch. Simplicity itself.
Cheers
Paul