Wiring question

[s2sailorlis]

On my 22, I’ve been starting to rewire some lights. In the attached panel below ( OEM) 2 battery switch panel, what is the purpose of the copper plate on left side of picture that connects across the circuit switches? I assumed it was a common ground. When I switch on a light, and put a dc meter across the pos and negative( The copper rod) I get no voltage. In fact all of the ground wires connect to that blue round thing on the right...The black wire with the yellow connector is where I had to connect the neg wire for my new deck light.

What’s weird is the black wire on the plate connects to the pilot light...The blue thing sits behind the voltage gauge..see other pix of panel front

[tjr818]

That looks like a positive buss to me. Put your meter on that and check the voltage to ground.

[mgphl52]

umm... sorry, but from that photo I can't make heads or tails of what you're asking

[fmueller]

In simple dc systems red is hot and switched and black or yellow are typically ground. (In simple 120 volt ac systems, black is hot, white is neutral, and green is ground.)

You can partially see (I think but can't be sure from the picture) there appears to be a heavy gauge wire (under the accordian covering) going from the end of that bar to the center post of your battery switch. That would suggest the bar is hot. As Tim says, you need to measure for voltage between that bar and ground of your battery. If your meter leads are too short you can extend with a length of small gauge wire.

If you are doing electrical work a decent meter is a must.

[gonesail]

looks like your deck light may not be connected to the negative bus bar .. wherever that is.

[s2sailorlis]

Thanks for identifying the bar as the hot connection. If that’s the case, what’s the other side of the switch opposite the hot bar? I had my meter connecting between that side of the breaker and the hot bar and didn’t get any reading.

[fmueller]

I think without more pictures we’d be guessing.

One sure fire way to suss it out is by measuring continuity not voltage on the ground side as I suggested with a wire back to the ground terminal of your battery.

If the panel has two bars, one is likely ground and the other the hot supply. If it only has one bar that is likely hot and the panel is really just a multi switch/breaker and there is likely a common ground point elsewhere.

If you don’t have a meter get one. Think of it as cheep insurance

[Steve Laume]

No offense intended here but from the questions you are asking, my best advise would be that you buy a book on marine electrical systems to go along with your multi meter. A simple one with all the information you would need is, The 12 Volt Bible For Boats.

You are not going to get a voltage reading by going from the positive bar and to the other side of the breaker. There is no ground bar in the original panel. All of the grounds on Raven went to the neg terminal on the battery meter when I got her. Do not count on all the wires being the right color for positive and negative. Many wires are color coded for their intended use and that is a good thing. Our boats didn't use yellow for ground in the original wiring, that came later to avoid confusion with AC hot.

That metal strap that holds the battery meter is your "ground bar". You will find that the big black wire goes to an engine bolt, Steve.

[s2sailorlis]

Thanks for input. And yes fair comment on getting a marine electrical book!

[wikakaru]

Here's a free book on 12 volt troubleshooting from Spa Creek Instruments: http://www.melody-in-blues.org/download ... ndbook.pdf

Smooth sailing,

Jim

[s2sailorlis]

Thanks much Jim.

Here's a free book on 12 volt troubleshooting from Spa Creek Instruments: http://www.melody-in-blues.org/download ... ndbook.pdf

Smooth sailing,

Jim