Newbie wiring question: Wiring components through a switch

[nhellbaum]

I am currently going through a boat I recently bought and am needing to install/fix some components run off of switches.

The boat has a switch panel with Bilge (on, off, auto), Aerator (on, off), Lights (on off), and ACC (on, off) switches.

I need to put in a whole new live well pump and run the wiring through the switch. My main question is how the + and - wires should be run and connected when going from the battery, through a fuse panel, switch, and then to the component. I assume the + from the fuse panel needs to connect to the switch and then run to the pump from there. Does there need to be a ground to the switc since the fuse panel is grounded from the battery? Where is the best place to ground the (-) wire from the aerator pump?

When running power to lights and other things, obviously the + comes from the fuse panel and switch. Is it bad practice to tap into any convenient ground wire closer to the item?

What components could/should be wired to the ACC switch? (fish finder, radio, etc)

Thanks!

 

[Grandad]

I'd start by trying to understand the existing system unless you're wanting to start from scratch. If you're new, you may not be aware that boats usually have essentially 2 electrical systems, most often both fed from the same battery. The engine will likely have a system that includes rudimentary gauges and trim controls whether this is an outboard or an inboard outboard powered boat. The boat itself will have another system that includes everything else. Unless someone has been tinkering, it's probably best to leave the engine control system alone.

The boat's other system will likely have a main electrical connection to the battery with a main relatively large (eg #10 AWG) positive wire feeding a fuse or breaker panel. All your miscellaneous lights and equipment should be fed via switches from fuses in the panel with smaller wires suitable for the size of the equipment and fused accordingly. There should also be a main (#10 AWG?) negative wire from the battery feeding a common bus bar or terminal strip to which negative wires from each of the pieces of equipment will also be connected.

To answer your questions:
The only time a negative (that you're calling a "ground") is needed at a switch would likely be if the switch itself contains an indicator light that illuminates when the switch is turned to on.
The aerator pump's negative should be connected to the common point for your negative electrical system. If the common point is forward and your aerator is closer to a stern mounted battery, you could run it directly back to the negative battery terminal. Every boat's layout is a little different. What you should avoid doing, is to simply locate the aerator's negative onto the handiest negative wire. It may work, but may not work well if you're overloading the negative wire by adding current flow to a wire that may not be suitable because of it's small diameter or because of it's length. This kind of "just make it work" approach can lead to problems later, particularly in terms of "voltage drop" which can cause malfunction in other equipment pieces.
I wouldn't have anything except engine controls connected to the ACC switch, if you're referring to the ACC position of the ignition switch.

I don't have a generic wiring diagram to offer you, but a number of other members have posted diagrams that you might want to look for. Maybe someone will post one here for you. I'll try to attach an ABYC document that may help, but it's got more detail than you're probably looking for.
- Grandad

 

[gm280]

nhellbaum, what you're asking to do is actually a lot harder to explain in words then actually do. Are you going to install another switch on that panel? You stated that you presently have an aerator. So why are you going to install an additional live well pump?

When you install any new circuit in a boat, you want to use the proper size wire to handle the current that the new circuit is going to use. And that is typically either 16 gauge or 14 gauge. It really depends on the current needs and the distance you are from the battery or supply tap at the switch panel. You need to run a positive wire to the new pump and then run a negative wire to the common ground point. DON'T simply tap into any existing ground. You have no idea how much that ground is currently handling in amps. So adding another ground to it can over load that wire. Run your new ground wire to the common ground point or the battery itself.

A simple circuit;

Start with a fuse or circuit breaker. From the positive buss bar or the battery, run the positive wire to the fuse or breaker and then from the fuse or breaker to the switch. From the switch, run the positive wire to the pump. From the pump run a ground wire back to the common ground buss bar or the battery. That is a complete circuit with a fuse/breaker and a switch to control the new circuit. Hope that helps.

 

[nhellbaum]

Thanks that helps a lot!

gm280- The boat currently has the aerator SWITCH on the panel but past owners have appeared to have completely removed the aerator pump and plumbing. So I am wanting to use the existing switch to hook an aerator pump system back up.

The pump itself will only be a couple feet from the battery (at the stern) so it sounds like direct connecting the (-) of the pump to the battery will be easiest. I can then feed the + from the fuse panel, to the switch and back to the pump.

 

[gm280]

Thanks that helps a lot!

gm280- The boat currently has the aerator SWITCH on the panel but past owners have appeared to have completely removed the aerator pump and plumbing. So I am wanting to use the existing switch to hook an aerator pump system back up.

The pump itself will only be a couple feet from the battery (at the stern) so it sounds like direct connecting the (-) of the pump to the battery will be easiest. I can then feed the + from the fuse panel, to the switch and back to the pump.

Okay, that sound good.

 

[nhellbaum]

Just a follow up-
The hose and snipped wires from the old intake were still at the stern tucked away! A tester light revealed that the wires are getting power from the switch also. Should be a fairly easy install after I track down a new live well timer (help).

The intake hole goes through the stern so should I get an angled intake pump or I found a 90 degree intake port??

 

[gm280]

Just a follow up-
The hose and snipped wires from the old intake were still at the stern tucked away! A tester light revealed that the wires are getting power from the switch also. Should be a fairly easy install after I track down a new live well timer (help).

The intake hole goes through the stern so should I get an angled intake pump or I found a 90 degree intake port??

I like the angled style. But a 90 degree can work if it is below the water line. Because those type pumps need water in them to prime and pump. They won't suck water into them for that effort. So either type will work, but the angle one allows the pump to sit level. JMHO