Wiring cabin lights in Serial

[sailingdog]

Actually, in any circuit, series or parallel.. you've only got one hot and ground leading back to the panel. In the case of 120 VAC, you've got a hot, ground and neutral.

[maccauley123]

So, if I:
1. Run a single wire, rated for the full amps expected, from a single cabin lights switch to a 5 gang fuse block.
2. From one of those set of posts run a single duplex wire to the first fixture both pos and neg.
3. From this same fixture run another wire to the next fixture and so on. This would essentially be a 3 wire splice, right?
4. Keep doing this until I reach the end of the port circuit.
5. Repeat for starboard circuit.

[duffer1960]

You are using the term series and parallel incorrectly. Reading your post, it sounds like you want to run one positive wire, and one negative wire through your boat for the lighting, and then connecting each light between the positive and negative wire. Yes, you could then say the lights are in "Series" the way they are physically located in the boat, from front to back, but they are actually electrically connected in parallel. This is how boats are already wired. I have one switch on my panel for the cabin lights. I turn on that switch and there is power delivered to each light fixture. Each fixture then has it's own switch. All of these lights are in parallel on the electrical circuit. There isn't one seperate pair of wires running to each light, that would be a boat-load (sorry for the pun, I couldn't resist) of wires! Your house is the same way, the lights may be considered as physically located in series throughout the house, put they are electrically connected to the wire in parallel, each light going from the hot wire to the ground.

[sailingdog]

Here... this should make things a bit clearer:

Both of these circuits are equivalent, but the lower one represents using a bus bar, represented by the heavier lines, and the red represents the positive wire and the yellow the ground...as per current ABYC IIRC. Black is no longer recommended for ground since the hot wire of an 110 VAC circuit is generally black, and mistaking the two could be very bad for you.

[duffer1960]

Sailingdog, great diagram. It shows how the circuits are identical, but look different. Maccauley123, imagine the resistor symbols as light bulbs, and you have your circuit.

[sailingdog]

Duffer-

It really depends on how the boat is wired... you can have the boat wired in series or parallel and have a single set of wires going to each fixture or in the case of a buss bar setup, a set of wires for each fixture. The top part of my crude drawing shows five lights in parallel using a single duplex wire... the bottom shows five sets of lights, also in parallel, but using five separate duplex wires.

The switch icon I'm using is for the circuit breaker for his "cabin lights' circuit... and doesn't indicate whether the lights are individually switched or not...

BTW, thanks.. it was a rough diagram I just did just now.

Originally Posted by duffer1960

You are using the term series and parallel incorrectly. Reading your post, it sounds like you want to run one positive wire, and one negative wire through your boat for the lighting, and then connecting each light between the positive and negative wire. Yes, you could then say the lights are in "Series" the way they are physically located in the boat, from front to back, but they are actually electrically connected in parallel. This is how boats are already wired. I have one switch on my panel for the cabin lights. I turn on that switch and there is power delivered to each light fixture. Each fixture then has it's own switch. All of these lights are in parallel on the electrical circuit. There isn't one seperate pair of wires running to each light, that would be a boat-load (sorry for the pun, I couldn't resist) of wires! Your house is the same way, the lights may be considered as physically located in series throughout the house, put they are electrically connected to the wire in parallel, each light going from the hot wire to the ground.

[maccauley123]

That was the way initially I thought to wire it. I then started reading and must have misunderstood, thinking that was serial. Trying to do it right I planned on using bus bars with a separate wire going to each light. That would be a boat load of wire which prompted my question, seemed like overkill.

Looks like I had the right idea to begin with. All other gear like VHF, GPS, Radio etc will be wired to separate circuits.

[duffer1960]

Good point you made about not showing the switches for each individual light. Therefore, maccauley123, imagine each resistor symbol as the whole light fixture, bulb and switch included. The switch shown in the diagram is then your main circuitbreaker.

Sailingdog, I didn't think lights would be wired in series, there would be too much of a voltage drop across each light, and they would be too dim; but I guess there may be an application for that. Also, if there was a switch in any fixture in the series application, opening that switch would shut off every light in the circuit.

[maccauley123]

Duffer and Sailingdog, thank you very much for your help, greatly helped my understanding of this.

[sailingdog]

Duffer—

I was specifically responding to when you said

There isn't one seperate pair of wires running to each light, that would be a boat-load (sorry for the pun, I couldn't resist) of wires!

in a previous post. If you used a buss bar, fuse box, or switch panel setup, like I did, you would have separate pairs running to each light.

Originally Posted by duffer1960

Sailingdog, I didn't think lights would be wired in series, there would be too much of a voltage drop across each light, and they would be too dim; but I guess there may be an application for that. Also, if there was a switch in any fixture in the series application, opening that switch would shut off every light in the circuit.