Question about boat electrical system

[Abenoit]

This may seem like a fairly straightforward and simple question but electrical is certainly not my forte'. I have a main power supply busbar and a fused switch panel that I will be installing at the helm of my starcraft rebuild. My question is do I need a separate bus to run ground wires from the switch panel to the negative terminal on the battery?

 

[GT1000000]

Re: Question about boat electrical system

This may seem like a fairly straightforward and simple question but electrical is certainly not my forte'. I have a main power supply busbar and a fused switch panel that I will be installing at the helm of my starcraft rebuild. My question is do I need a separate bus to run ground wires from the switch panel to the negative terminal on the battery?

Hi "Abenoit",
You will get some help in this section of the forum, but the best info on anything related to boat electrical can be had here

 

[Don S]

Re: Question about boat electrical system

Assuming the battery is at the back of the boat and the helm is near the center or forward, a negative bus bar on the back of the boat just keeps things neater for hooking up the negative wires from blowers, bilge pumps, stern lights, etc. up to instead of.

 

[Silvertip]

Re: Question about boat electrical system

You probably could use two negative buss bars. The one at the helm would serve as the ground point for all accessories at the helm and forward of the helm. The negative buss at the stern would serve all accessories behind the helm (fuel tank, bilge pumps, live well pumps, blowers, etc.).

 

[gm280]

Re: Question about boat electrical system

In my opinion... I like both a positive AND a negative buss bar, block, or whatever you want to call it. Reason for that is it is so much easily to connect things up and know where everything goes. The positive buss bar/block needs to be properly fused from the battery forward and all branches from that buss/block as it branches out also needs to be fused for whatever each branch is feeding/requiring to make things safe. I even like to label each branch to let me and future owners know what they are for. Proper wire dressing is a huge issue with me. It not only allows you to troubleshoot problems easier, but also makes things safer... The time you spend doing the proper wire dressing now will pay for itself in the future if problems do arise... But as I prefixed this post, this is just my opinion...

 

[UncleWillie]

Re: Question about boat electrical system

... I like both a Positive AND a Negative buss bar, block, or whatever you want to call it. ...The positive buss bar/block needs to be properly fused from the battery forward and all branches from that buss/block as it branches out also needs to be fused for whatever each branch is feeding/requiring to make things safe...

A Positive Bus Bar/Block is what is commonly called a Fuse Block.
Many contain a Negative Buss Block for convenience.

 

[Abenoit]

Re: Question about boat electrical system

Thank you for all the replies.
After a further inspection I realized that the switch panel has a positive terminal for connecting to the battery so I will not be needing an external positive busbar. It also has a negative terminal for connecting to the battery as well. My question now is, the directions call for the negative wire from each appliance to be connected to a ground somewhere on the boat. Can I connect the negative/ground on all of my appliances to the busbar and also run that wire to the negative lead on the battery?

 

[UncleWillie]

Re: Question about boat electrical system

Ground, is Ground!

Do not lose track of the fact that the Ground path has the same current the 12v Supply wires carry.
As long as the Ground wiring is at least as heavy at the Supply wiring you will be fine.

 

[Silvertip]

Re: Question about boat electrical system

Ground is wherever you find it but ultimately on a boat is the NEGATIVE terminal of the battery. Since you said the switch panel has a negative connection, run the same size negative and positive wires to the panel. Run the same size negative wire from the panel to a negative buss bar. All accessory negative leads then go to the buss bar. Why run them all the way back to the battery? Consider that you wouldn't need to use the negative connection on the panel. Run the negative wire to the buss bar. Accessory grounds still connect to the buss bar. There is no need for a negative connection on a switch panel unless the switches have an internal light or that negative connection is intended to be used as a buss (in which case there would be several negative connection points).

 

[Abenoit]

Re: Question about boat electrical system

Thanks again for the replies. You nailed it Silver! There is an internal LED in each rocker switch that lights up when in the on position. Now that I know I can run a ground/negative wire from the battery to both the switch panel and the busbar I should be good to go!

 

[Silvertip]

Re: Question about boat electrical system

Thanks again for the replies. You nailed it Silver! There is an internal LED in each rocker switch that lights up when in the on position. Now that I know I can run a ground/negative wire from the battery to both the switch panel and the busbar I should be good to go!

Back up a bit. You run the HEAVY black wire from the battery to the buss bar. You run accessory grounds to the buss bar, not the ground connection on the switch panel. That switch panel ground is ONLY for the ground side of the LEDs in the switches. therefore a smaller, 16 gauge wire runs from the switch panel ground to the buss bar.

 

[Abenoit]

Re: Question about boat electrical system

I follow you. But I would still be running the same gauge wiring from the the battery to the switch panel AND buss bar or would I run the ground/negative from the battery to the buss bar and then from the bussbar to the switch panel?

I hope Im explaining my question properly.

 

[Silvertip]

Re: Question about boat electrical system

One more time: There are two types of ground (negative) connections that can be incorporated into a switch panel. Obviously you run a large gauge red wire (positive) to the switch panel because it is what feeds all of the switches. Some switch panels have a ground BUSS built into them so all ground (negative) wires from accessories can connect there and you would NOT need a buss BAR because the switch panel has one. You can tell if it is intended to be used as a buss because there will be several NEGATIVE attachment points. If there is only one negative connection, that is NOT a buss connection -- but rather a ground connection for the internal LEDs on the switches. You don't need a 10 gauge wire for that connection because the only current it carries is for the LEDs. So NO! You do not run heavy wire in that scenario to the switch panel THEN to the buss bar. If you must use a buss bar then the the large gauge wire runs directly from the battery to the BUSS BAR. The negative connection from the switch panel goes to the buss bar but again, using 16 gauge wire. But here's a thought -- why not decide on a switch panel and then post a link so we can stop guessing.

Here is a fuse panel with a built-in NEGATIVE BUSS. A switch panel with one would look similar.



Here is a typical "Boat/Helm" wiring diagram. You can use a master cutoff or not. It is purely optional.


Here is a switch panel with lighted switches. See the small black wire at each switch. That's the ground for the internal LED. There is no BUSS connection on that panel. That small wire goes TO the negative buss.