electrical question

[Jdpmus]

I am restoring a CD 25 and want to add an accessory outlet to the main panel. When I remove the panel, I see white wires from somewhere crimped to the black of the switches. Which one is positive, the common wire that runs through each switch, or the other terminal connected with black wire? There are a number of spares that I can wire to, but I'm not sure where their white wire leads. I picked a spare and tried it, but there was no juice.

Ideas?

[Oswego John]

Jdpmus and all,

Here are a few basics so everyone is on the same page.

When working with DC power, batteries, generators, rectified alternators, etc, the positive "hot" feed is normally red insulation. The DC return negative is mostly black insulation.

On an average single pole (SP) switch, either it is on or off. This type of switch has two terminals. Power enters the switch on the "line" terminal which is often the upper terminal. The line terminal is fed by a red wire.

The power passes theough the switch and is controlled either on or off. The controlled power leaves the switch via the second terminal, the "load" terminal. Here is where things can get fuzzy.

When the hot power leaves the switch and travels en route to whatever the switch controls, say a light bulb, it is still a hot wire, a controlled hot wire. Some people continue to use the red color for the "load" feed. Others use a different color. That load wire from the switch is not a negative return wire. It is still hot as it feeds the bulb.

The other wire coming from the bulb is considered a return wire to the battery source. It is normally black. When tested, it should show a negative polarity.

You state that white and black wires are crimped together. For the sake of uniformity, the same color wiring (red) should feed all the line terminals of the switches. Maybe it wouldn't hurt to do a panel rewiring job.

One other point. It is questionable policy to switch the return wire. Always try to switch the feed wire of a unit.

Using a color coded wiring scheme makes trouble shooting so much easier. Rely on your multimeter to determine polarity.

These are a few basics to get started on the right foot.

Good luck,
O J

[Leo MacDonald]

PM Sent.

[Jdpmus]

Thanks, guys.

[Neil Gordon]

On old boats, the color of the wire is often based on what was lurking at the bottom of the tool box at the time. Use color as a hint but I'd do as others have suggested and test for polarity.

[Steve Laume]

First off if you are asking this question, be careful! AC current is not a trivial thing to mess with.

I have a feeling Leo probably already PMed you some very good advice. OJ's red and black may be today's standards in the marine industry but are not likely to be what you have on your boat.

In typical home wiring you have black/positive, that goes to the breakers, white neutral and a bare ground.

On Raven I believe Cape Dory used a black/positive, white/neutral and a green/ground. I May not be remembering the black and white correctly. The positive wire should be going to the breakers. This wounds like white in your case.

With the questions you are asking the best advice that could be given is to pick up a copy of Don Casey's Sailboat Electrics Simplified or some other book on marine wiring. The Casey book is very good to have not only for the project you have planned but to better understand your entire electrical system, Steve.

[Jim Davis]

Note this is based on intimate experience with two 25's electric panels and I'm sure there are variants. CD appears to have used white for the DC positive and black for the DC negative. The early panels used fuses and simple toggle switches - all very straight forward. Later they went to an illuminated rocker switch. For these switches they lead the DC negative to the switch for the light bulb in the switch. For these the positive (white) comes into the panel at the fuse to the switch to the load. The negative (black) goes to a separate lug to give power to the idiot light in the switch. All of the above is as it was done and does not conform to any standard. I suggest that you check every step with a voltmeter. Also you will find it hard to pull new wire in, other than near the switch panel. They basically laid the wiring harness in between the deck and overhead liner and glued it all together. Also you will find they used a lot of wire nuts in making their connections, the only factory crimps I have found on older 25's were close to the panel.

[Jdpmus]

Thanks, Jim. I have the older version with the wire nuts crimped close to the panel with a white wire joining the black from the other side of the switch. I think the spare circuit I was trying to use is not hooked up to positive or anything else.

[Kevin Kaldenbach]

There is something more important that you should consider here and that is getting better familiarized with basic wiring before you start. While your at it get a good understanding of the role electricity plays in corrosion. I understand that a boat on my dock sunk because the thru hulls were ate up by stray electricity from questionable wiring.

For alternating current I would recommend a book called Wiring Simplified and for direct current perhaps an automotive text book. I assume you goal is to improve the existing wiring in your boat but if your not familiarized with the proper way to crimp a wire end on or what gauge of wire is best for the job your efforts may not pay off. I have seen very expensive equipment burn down to the ground because the manufacture did not pay attention to their wiring job. I don’t mean to discourage you nor do I think it takes an expert to do the job.

[Oswego John]

For those who are planning or actually doing electrical updating on their boats, the following might prove helpful.

http://www.acbsphl.org/Tips_and_hints/ABYC_Wiring.htm

Good luck,
O J

[Dean Abramson]

First off if you are asking this question, be careful! AC current is not a trivial thing to mess with.

Steve, I think he is talking DC. ?

[John M]

I have a Cape Dory 30, my owners book references models22-30
In the book the panel is depicted as having primarily control of the positive side only. The only Neg ref on the panel is one common to provide ref to the battery meter.

What are you measuring the presence of voltage in reference to?
If you did not use the neg of battery or some other common point when taking your measurment this could be the cause.

If a copy of the pages of my owners manual woul help, I could provide.

[sfreihofer]

Hi J;

If your CD 25 is anything like mine (don't ASS-U-ME), I can tell you what I found. Your results may vary.

The CD 25 has no AC circuit, so you are dealing with 12V DC. This should be stated on the control panel.

In general, only the positive side of the circuits go through the panel. There may be exceptions for gounding panel lights and meters, but all of the controlled circuits should be positive. Check this.

On my boat, the positive (red) battery cable fed a common bus (bare wire) which went through one side of each circuit breaker, so each breaker is energized by the positive battery cable. Each breaker supplies a separate circuit. The other side of the breaker went to its respective switch for the circuit. These wires were all black. All circuit breakers were 20 amp, which is too much to adequately protect the wire it feeds.

From there, the wires lead to a connector, and the colors mean nothing... you have to trace each circuit through the connector. After the connector, the wiring becomes a more conventional (although now obsolete) red/black. More than one wire may be wired together, or branched, as they spread throughout the boat. They are bonded between the deck and the liner, so they cannot be removed or replaced. They must be either re-used or bypassed.

If a picture is worth a thousand words, this may save my breath:
http://www.reefroof.com/OldElectric.htm

I am restoring a CD 25 and want to add an accessory outlet to the main panel. When I remove the panel, I see white wires from somewhere crimped to the black of the switches. Which one is positive, the common wire that runs through each switch, or the other terminal connected with black wire? There are a number of spares that I can wire to, but I'm not sure where their white wire leads. I picked a spare and tried it, but there was no juice.

Ideas?