Switch Panel Wiring Question

Jacktar · Jul 25, 2019

If the po used this panel to interrupt each circuit he is switching the positive side of all circuits run to it. In other words the red input is positive to panel and black is return to postive source probably the battery or vice versa. The negative for each circuit should be an uninterrupted line back to the battery negative post or most normally to a negative bus that connects to the battery negative pole. See attached circuit diagram from my c22.

jviss · Jul 25, 2019

AndreInPortland said:
It appears the PO ran power from the battery to the bottom circuit on the panel

Top or bottom, doesn't matter.

I would eliminate the blue wire nuts, and put in a small negative bus. Otherwise you'll have to run your radio's ground back to the battery, or somewhere on the ground wire, like that blue wire nut on the black.

Leeward Rail · Jul 25, 2019

I agree with @jviss

In fact I would get positive and negative buss bars and run the battery wires to them.
Then run power to from the buss bars as needed, with ring terminals.

Wire nuts have no place on a boat.

kloudie1 · Jul 25, 2019

As Sea Dog diagram shows, you really don't need a positive buss. The big red entering from the bottom to the circuit breakers is jumpered to provide power to all the breakers.. The negative lead is there to allow the light bulbs in the switches to work. A negative buss would be good .. You could run a continuous 10ga wire to the breaker hot to eliminate the wire nuts, and when the neg buss is there, a continuous 10 ga black back to the battery..

jviss · Jul 25, 2019

kloudie1 said:
The big red entering from the bottom to the circuit breakers is jumpered to provide power to all the breakers..

That daisy-chaining of the plus bus can be a problem. All of the current for downstream circuits flows through that first double-wire female spade connector crimp.

When I got my Catalina 36 it did the same thing, and some of the wires, and connectors, and fuse holders were burnt! A fire waiting to happen.

I encourage doing it over with plus and negative bus, and point-to-point for each fuse to the plus bus.

Better yet, replace that panel with a modern panels, such as from Blue Sea Systems.

LeslieTroyer · Jul 25, 2019

As someone else said ditch the wire nuts (I see a yellow one in addition to the blue. Wire nuts belong in houses not boats. They are NOT approved by ABYC for boat wiring!!! Put in a terminal block with ring or bent fork connections. Butt connections for joining two wires is ok.

AaronD · Jul 25, 2019

Andre: There's lots of good advice here. Especially the suggestion to add a negative bus bar. E.g. something from the selection at https://shop.sailboatowners.com/cat.php?6180.

If there's ever a chance you'll add a battery monitor, mount the bus somewhere you can add a shunt as well (you'd then run the negative from the battery terminal to the shunt and from there to your negative bus).

Remember that your breakers are to protect the wiring. So check the breaker sizes and ensure the wiring on each circuit is large enough to handle their maximum loads (or, alternatively, replace breakers with ones small enough for the wires they feed). There's a table at https://www.westmarine.com/WestAdvisor/Marine-Wire-Size-And-Ampacity, including sizing for 3% and 10% voltage drop (what you should design for when wiring), and maximum current (which you need to protect each wire from with fuses or breakers).

The ABYC standard is that the positive wires be protected within 7 inches of the battery terminal. The easiest way to do that is with a terminal-block fuse, like @Maine Sail describes at https://forums.sailboatowners.com/index.php?threads/battery-fuse-sizing-how.130775/.

One minor note re:

kloudie1 said:
a continuous 10 ga black back to the battery..

Black has been the standard for DC negative for a long time, but marine practice (maybe by ABYC? I'm not sure) has moved from black to yellow for this application. The reason is that many boats now have both AC and DC systems, and in AC wiring, black is used as the hot lead. You don't want to confuse the two! If there's ever any chance you might add shore power or an inverter, you might start out your wiring with yellow for DC negative.

Hardhead · Jul 25, 2019

Jacktar said:
View attachment 167571

This is probably a very silly question, as I am definitely no electrician, at all. I was studying the wiring diagram above, and saw you show a sub bus, carrying the negatives from the panel to the battery negative. Are there as many wires coming out of the sub bus, as coming in? I'm trying to understand what effect the sub bus has on the system. I apologize if it's obvious...

Leeward Rail · Jul 25, 2019

Hardhead said:
Are there as many wires coming out of the sub bus, as coming in? I'm trying to understand what effect the sub bus has on the system.

The idea of a buss is to distribute power.
So you can have 1 large cable feeding the buss and a bunch of smaller cables running from it.

It also allows easy secure connections and keeps things organized..

Kinda like a bunch of wires going "from" a wire nut but one "going in".. But without the fire hazard. Hehe

I have large cables running from the battery to 1 Positive and 1 negative buss bar.
The individual positive feeds to the panel run from the positive buss and the grounds from each circuit run to the other.
All are attached by ring terminals.
All positive circuits are protected by fuses or breakers.

The previous owner or our boat had a bunch of smaller ground wires, including some combined together with wire nuts.. Running back to the battery. A tangle of wires with questionable connectors.

Hardhead · Jul 25, 2019

Leeward Rail said:
The idea of a buss is to distribute power.
So you can have 1 large cable feeding the buss and a bunch of smaller cables running from it.

It also allows easy secure connections and keeps things organized..

Kinda like a bunch of wires going "from" a wire nut but one "going in".. But without the fire hazard. Hehe

I have large cables running from the battery to 1 Positive and 1 negative buss bar.
The individual positive feeds to the panel run from the positive buss and the grounds from each circuit run to the other.
All are attached by ring terminals.
All positive circuits are protected by fuses or breakers.

The previous owner or our boat had a bunch of smaller ground wires, including some combined together with wire nuts.. Running back to the battery. A tangle of wires with questionable connectors.

Thanks Leeward - I got that part okay I think - it's that I thought in the diagram, the "NEG" rectangle was probably also depicting a negative bus bar as well, which led me to wonder why there would be 2 negative bus bars in that set-up. (if both Sub Bus and NEG were negative bus bars.) It looks like 3 colored wires are going into the Sub Bus, and the same 3 colored wires also coming back out. I might be over-analyzing the diagram, or just completely mixed-up...

Here's another silly question - a lot of bus bars seem to have 2 larger ring terminals on the ends, and of course, the multiple sub-wire terminals connecting in the middle of the bus bar. My thinking was the negative cable from the battery or ground is intended for the 1 large ring terminal - but I'm sketchy what in particular is intended for the opposite side 2nd larger ring terminal?

JimInPB · Jul 25, 2019

Hardhead said:
Thanks Leeward - I got that part okay I think - it's that I thought in the diagram, the "NEG" rectangle was probably also depicting a negative bus bar as well, which led me to wonder why there would be 2 negative bus bars in that set-up. (if both Sub Bus and NEG were negative bus bars.) It looks like 3 colored wires are going into the Sub Bus, and the same 3 colored wires also coming back out. I might be over-analyzing the diagram, or just completely mixed-up...

Here's another silly question - a lot of bus bars seem to have 2 larger ring terminals on the ends, and of course, the multiple sub-wire terminals connecting in the middle of the bus bar. My thinking was the negative cable from the battery or ground is intended for the 1 large ring terminal - but I'm sketchy what in particular is intended for the opposite side 2nd larger ring terminal?

If there are two large terminals & several small terminals on a single strip, one big terminal is for the feed & the other large terminal can be for a run to a second buss bar or a heavy load.

JimInPB · Jul 25, 2019

AndreInPortland said:
Hey all,

My VHF radio installation is the project that just won't end. I've installed an antenna at the top of the mast, fished coax through the mast, drilled and installed a through-deck fitting for the coax, and mounted the VHF radio next to the companionway tucked in the quarter berth.

The last step (I pray) is to run power to to the radio. But, I can't make heads or tails of the wiring on my switch panel. Can anyone provide any guidance as to how I tap into the panel to power the VHF radio? The labels on the switch panel are... interesting. There is definitely no bilge on the boat, nor an AM/FM radio. But otherwise, the top three switches all work as advertised. (I think they meant to label anchor light as steaming light, but I digress.)

So, how in tarnation do I run power from this switch to the VFH radio?

Here's the back of the switch, and the front.

Much appreciate any guidance.

- Andre

A lot of guys use those 1/4" slide tab connectors, but I don't like them. I feel that ring terminals & screws give much more reliable connections. Those wire nuts have no proper place on a boat. All wire strands should be tin coated, per ABYC.

jviss · Jul 27, 2019

Another alternative may be, until you replace the entire panel, to install a fuse "block" near the panel, and just feed the switches from there. I might have one around that has both plus and minus buses; if I can find it you can have it for postage. Might take a few days for me to locate it.

You wold just energize the fuse block directly from the battery, install the correct size fuses (AGC), and wire directly to your switches, skipping your existing panel's circuit breakers.

jviss · Jul 28, 2019

AndreInPortland said:
@jviss Thanks for the offer! I’ll take you up on that if you can locate it. If not, I like this idea anyways, so if yours doesn’t get located I might just buy one.

Thanks again,
Andre

No prob, I'll look for it tomorrow, after I'm home from my boat. I have two, but as I recall, one has a plus and neg bus.

mll · Oct 27, 2019

I would have both neg. And pos. Bus bars. From the pos. Bus bar run individual wiring thru circuit breaker to item to get power, from the neg. Bus bar run individual wiring theough switch to provide the ground for item wanted to turn on. This illiminates higher current flow through switches as the switch would be on the low amperage side of the load.

Switch Panel Wiring Question

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