How do I wire cabin lights in one circuit?

[Lake-Effect]

Accessibility to all the connections is key, else you'll never be able to troubleshoot and repair/replace things. Connections can be behind fixtures (the pigtails), in cupboards or lockers if protected from damage, or behind removable plates or panels.

If you can get to every light location with a feeder or two, then you can run just one pair of wires as a feeder and splice in the the light pigtails behind each light. Otherwise it's best to pick some convenient location for a terminal strip, run your feeder to that, then run a separate pair from there to each light.

Feeders must be sized to carry the TOTAL current with every load of that circuit on, and never smaller than #16 AWG. The runs to individual LED fixtures can be a 18AWG sheathed cable (ie two conductors, then another jacket over that.) - ABYC

As suggested, splitting your interior lighting into two or more circuits is a good idea, so that one failure doesn't plunge you into total darkness. I don't know many boats whose lighting could be done with just one feeder anyway.

Soldering the pigtail directly to a heavier feeder isn't terrible in my personal opinion, because the LEDs take low current and seldom short out... but if it's a running feeder you're tapping into, how do you slide tubing onto it? You can tape those up, but that always looks like hell after a while. Crimped connections and where needed, terminal strips are the better choices.

Any power-carrying conductors, including your LED feeders, should never have splices where solder is the sole means of connection. (ABYC and just about every other electrical code)

Some things I disagree with;

The negatives can go to the nearest negative terminal

No, please don't do that. Definitely against ABYC stds. This practice leads to wiring chaos, and you can easily end up with a popular negative connection putting excess current on one return conductor. Which are unfused, therefore a potential fire hazard. You might also be tempted to connect to a ground bonding conductor, which is also bad.

I'm not a fan of insulation piercing or displacing connections. They're used some places because they're cheap, easy and fast, not because they're the best. They don't always work well with fine stranded wire, and can often take out some strands. In just about every type of location except for the driest and most protected (eg NOT marine), I see them often fail after a few years. Also not ABYC-approved.

Every boatowner should have at least one decent book on boat wiring, especally if they're new to this. Best $50 you'll spend.

[boeing1]

agree, use only marine wire

[Cadence]

Originally Posted by Sandibar

I'm redoing the lighting on my boat as well. The negatives can go to the nearest negative terminal - all negatives are connected on a normal boat electric system. Not sure if I understand your problem - three wires - but you could just pull a positive wire from a common terminal to each luminaire separately, or if you want to chain wire them, why three wires?

Anyway, I'm using these connectors from Wago to connect multiple wires:



You don't need an end splice on the wires for these and they take a wide range of wire sizes.

Double wire is good if you bring all negatives back to the electric panel separately (not necessary, afaik).

JMHO. I don't think you want to parallel the lights like Christmas tree lights.

You will find the nisser busting your balls. Even though they are low amperage run each back to a bus.

[Skuzzlebutt]

Originally Posted by Lake-Effect

Accessibility to all the connections is key, else you'll never be able to troubleshoot and repair/replace things. Connections can be behind fixtures (the pigtails), in cupboards or lockers if protected from damage, or behind removable plates or panels.

If you can get to every light location with a feeder or two, then you can run just one pair of wires as a feeder and splice in the the light pigtails behind each light. Otherwise it's best to pick some convenient location for a terminal strip, run your feeder to that, then run a separate pair from there to each light.

Feeders must be sized to carry the TOTAL current with every load of that circuit on, and never smaller than #16 AWG. The runs to individual LED fixtures can be a 18AWG sheathed cable (ie two conductors, then another jacket over that.) - ABYC

As suggested, splitting your interior lighting into two or more circuits is a good idea, so that one failure doesn't plunge you into total darkness. I don't know many boats whose lighting could be done with just one feeder anyway.

Soldering the pigtail directly to a heavier feeder isn't terrible in my personal opinion, because the LEDs take low current and seldom short out... but if it's a running feeder you're tapping into, how do you slide tubing onto it? You can tape those up, but that always looks like hell after a while. Crimped connections and where needed, terminal strips are the better choices.

Any power-carrying conductors, including your LED feeders, should never have splices where solder is the sole means of connection. (ABYC and just about every other electrical code)

Some things I disagree with;
No, please don't do that. Definitely against ABYC stds. This practice leads to wiring chaos, and you can easily end up with a popular negative connection putting excess current on one return conductor. Which are unfused, therefore a potential fire hazard. You might also be tempted to connect to a ground bonding conductor, which is also bad.

I'm not a fan of insulation piercing or displacing connections. They're used some places because they're cheap, easy and fast, not because they're the best. They don't always work well with fine stranded wire, and can often take out some strands. In just about every type of location except for the driest and most protected (eg NOT marine), I see them often fail after a few years. Also not ABYC-approved.
Every boatowner should have at least one decent book on boat wiring, especally if they're new to this. Best $50 you'll spend.

__________________________________________________ __

Generally, I don't quote the author, but this one is IMPORTANT. Listen to him, he knows. Forget the other 'opinions'. I'm not sure why people to don't know what they are talking about insist on offering their so-called knowledge. People, if you don't have much expertise on a subject, why lead some poor OP down a track he will later pay for your misinformation.

IMHO, this site has become more of a 'chat room' than a forum. Let's try to keep at least a modicum of valid info in our posts... Please!

[Ebtvision]

Ok so I'm liking the idea of having a feeder to a terminal strip and then having some of the lights going there.

I'm not too concerned with doing port/aft light circuits because 1. I don't want to take up another switch on my panel, 2. I don't really sail at night much at all so it's not necessary. (we just day/weekend sail around the Eastern end of Lake Ontario).

Now for this terminal strip (same as a bus bar right?) ...

I don't understand how it would go to one strip. Wouldn't I need two strips (one for pos, one for neg?). I keep hearing talk of how things can be condensed to one negative wire and the positives are what matter, but this is what is confusing the heck out of me. I've read don casey's book a million times and I still don't understand how it works. It's very frustrating.

If this 'feeder' cable goes to a terminal strip somewhere forward that's safe and secure, it would have to be two terminal strips right? Each fixture would have both their leads going to the respective strips ... I don't get how this would be possible to do with one strip. I understand how to calculate loads and size the wires properly but I cannot wrap my head around how negative wires seem to not always run together with positives.

(for example, a friend told me to write my spreader light and deck light which will be two different circuits, using different positives but the same negative. I don't get it).

[Lake-Effect]

Originally Posted by Ebtvision

Now for this terminal strip (same as a bus bar right?) ...

I don't understand how it would go to one strip. Wouldn't I need two strips (one for pos, one for neg?). I keep hearing talk of how things can be condensed to one negative wire and the positives are what matter, but this is what is confusing the heck out of me. I've read don casey's book a million times and I still don't understand how it works. It's very frustrating.

If this 'feeder' cable goes to a terminal strip somewhere forward that's safe and secure, it would have to be two terminal strips right? Each fixture would have both their leads going to the respective strips ... I don't get how this would be possible to do with one strip.

A terminal strip is NOT a bus bar.

A bus bar is made of a conductive metal, and has a single row of screws. Yes, the idea is that every wire going to a screw on this bus bar is going to be connected together, so that they are all fed by a feeder wire going back to the panel.

If you were trying to feed a bunch of loads from the same circuit (eg cabin lighting), then yes you'd need two bus bars - one buss (positive), fed by a panel fuse or breaker, and one* buss (negative) fed from the panel's common negative point

(* if your lighting distribution point is going to be behind the panel, then sometimes you can use the DC panel's own negative bus bar which will also be behind the DC panel, instead of needing a separate buss for the lighting negative)

Here's a bus bar:






A terminal strip is a series of connections in pairs, mounted on a non-conducting base. Each pair is isolated from every other pair.

Here is a terminal strip:


Since each pair is insulated, you can wire a terminal strip in different ways. You could jumper every second terminal together to create one complete feed point for your lights, ...but I don't want to confuse you.

The best idea in your case is probably to get two small buss bars. Tell the folks at your favourite chandlery what you're up to, tell them how many fixtures you need to connect up and they will suggest the right-sized bars.

If you're at all tentative about working behind your panel, maybe a friend or a professional can get you started by installing bus bars wired to the right-sized breaker/fuse, then you can complete the wiring from there to each LED fixture.

I understand how to calculate loads and size the wires properly but I cannot wrap my head around how negative wires seem to not always run together with positives.

(for example, a friend told me to write my spreader light and deck light which will be two different circuits, using different positives but the same negative. I don't get it).

Marine "triplex" is pretty common, most often used for boat AC wiring. This sheathed cable contains 3 wires (usually white, green, black). It's possible to use white and green for two positive feeds, and the one black wire as a single negative return. (label the ends please!!)

For example, if you have a masthead light fixture with a nav light and an anchor light, you can run one piece of triplex up the mast: white for nav +, green for anchor +, black as the negative for both.

Or if you have a combined steaming light & deck light fixture, triplex can be used here too: white for steaming +, green for deck light +, black for both negatives.

As long as the gauge of the black wire is sufficient to carry the combined current when both lights are on, then this is quite safe.

[Cadence]

Originally Posted by Ebtvision

Ok so I'm liking the idea of having a feeder to a terminal strip and then having some of the lights going there.

I'm not too concerned with doing port/aft light circuits because 1. I don't want to take up another switch on my panel, 2. I don't really sail at night much at all so it's not necessary. (we just day/weekend sail around the Eastern end of Lake Ontario).

Now for this terminal strip (same as a bus bar right?) ...

I don't understand how it would go to one strip. Wouldn't I need two strips (one for pos, one for neg?). I keep hearing talk of how things can be condensed to one negative wire and the positives are what matter, but this is what is confusing the heck out of me. I've read don casey's book a million times and I still don't understand how it works. It's very frustrating.

If this 'feeder' cable goes to a terminal strip somewhere forward that's safe and secure, it would have to be two terminal strips right? Each fixture would have both their leads going to the respective strips ... I don't get how this would be possible to do with one strip. I understand how to calculate loads and size the wires properly but I cannot wrap my head around how negative wires seem to not always run together with positives.

(for example, a friend told me to write my spreader light and deck light which will be two different circuits, using different positives but the same negative. I don't get it).

Someone posted the difference between a bus bar and a terminal strip. As far as wire colors I am not sure that is international? I bought a boat built in England from a South African. It was a cluster f#ck on wire colors. I had some blue?

[Skuzzlebutt]

From the OP's posts, I'd strongly suggest that he get someone with a bit of marine electrical experience ( i.e., training) to advise and/or assist. Reading through the above posts describe everything from somewhat correct to just plain stupid.

This is unfortunately not the place to get advice such as you are seeking. It ought to be, but we have too many members all-too-eager to pontificate without the knowledge to back it up. You probably won't set your boat on fire by following (most) of their advice, but then again.... do you want to take that chance?

There are a few of us who could give the correct advice, but why bother? The OP is so confused by the range of answers, he wouldn't know which to choose anyway.

It's sad that this forum has degenerated to this state.

[seabreez]

Originally Posted by Sandibar

I'm redoing the lighting on my boat as well. The negatives can go to the nearest negative terminal - all negatives are connected on a normal boat electric system. Not sure if I understand your problem - three wires - but you could just pull a positive wire from a common terminal to each luminaire separately, or if you want to chain wire them, why three wires?
Double wire is good if you bring all negatives back to the electric panel separately (not necessary, afaik).

My advice is never use the vessels ground to return to the battery. Return all grounds back to the panel. You can connect more than one light per circuit when using LED lights. Also if running many circuits... label the circuits for further reference. Label all circuits that you know! I also make a diagram of the circuits that I know and file them with your documents, or use a ship's main wiring diagram. Over the years you will refer to it... guarantee! I also install wiring in looms. Make it neater and less confusing when looking for certain circuits.

[Alika]

By all means use two circuits even if you aren't afraid of the dark.
Tinned wire, crimp connectors, heat shrink. Label everything. You always think you will remember where that wire runs but you won't and the next guy certainly won't know. Bundle wires snugly not tight. Wise to leave slack because when you need to swap a dud fixture out and cut off the crimp connector, leads get shorter. How many times have I found two crimp connectors close together because somebody got caught short.

[MarkSF]

So what I did was take one of the terminal strips, and use these to turn half of it into a little positive bus, and half to negative :

http://www.amazon.com/Blue-Sea-Syste...N%3DB000K2IL1I

[Ebtvision]

Originally Posted by Lake-Effect

A terminal strip is NOT a bus bar.

A terminal strip is a series of connections in pairs, mounted on a non-conducting base. Each pair is isolated from every other pair.

Here is a terminal strip:

This just confuses me more. Thanks for pointing out the difference visually between the two but here's where it just frustrates me to no end ... in Don Casey's book it says a terminal strip is what you're calling a bus bar:



And assuming what you showed me a terminal strip is correct, I can't understand how a terminal strip would be used instead of a bus bar. Would it be so multiple terminals can go on the same post and thus eliminate a three way butt connector or splice?

[Ebtvision]

Originally Posted by MarkSF

So what I did was take one of the terminal strips, and use these to turn half of it into a little positive bus, and half to negative :

http://www.amazon.com/Blue-Sea-Syste...N%3DB000K2IL1I

This sounds like a great solution rather than two separate buses!

[rwidman]

I have never seen so much bad advice in one place! Especially the use of "bell wire" to cancel out magnetic fields! Insulation piercing connectors are a poor choice for a boat. So is soldering. Wiring boat lights is nothing like wiring a Christmas tree.

Duplex cable is good and neater and easier than individual conductors. Crimp connectors are the best for marine use.

If I'm understanding this right, I'll be connecting three wires for each lead (pigtail negative, previous negative, next negative), (pigtail positive, previous positive, next positive) but what's the best method to secure each three-way connection together?

You are understanding this right. Often, you can insert the pigtail and one of the wires into the same side of a butt connector and the other wire into the other side. If not, you can buy butt connectors designed to join wires of different sizes. Put the pigtail and one wire in the larger side and the other wire in the smaller side.

Usually, the connections will fit behind the fixture so they remain "accessible", just unscrew the fixture.

In theory, the overcurrent protection should be based on the size of the pigtails but that may not be possible. I chose five amps for my interior LED lighting because that was the smallest breaker I could find and the (measured) current with all the fixtures on was about two amps.

[Sailorman Ed]

Ebtvision,
Assuming these are small LED light (without switches on the light ?)
They probably came with #20 wire pigtails, and probably not even tinned. They probably pull 0.1A, so even all 6 will only give you a load of less than 1 amp. 16 ga mentioned before is rated for 25 amps. While a bit more difficult to find, #18 marine grade duplex is rated for 20 amps outside an engine compartment, 20 x your load and is much easier to thread in tight spaces. Yes, the pusists will say it is not to ABYC code but that applies to building new boats. You really want a 5 amp breaker or fuse. The terminal strips ( the pic in Don Casey's book is a buss bar) with jumpers would work just fine. Just be sure to fasten them to something solid. I use these.to connect the fixture to the wire, easy to take apart later and handle the small diameter wire. Cheap too!! I get them in long strips and cut off the number I need. And no exposed metal that could short out. They come in small sizes too.
I do use buss bars to clean up larger wires and then run a large ground back to the battery. If you use buss bars for the positive side, suggest getting one with a clear insulating cover. And do label your wires, even if you only use a Sharpy on the white sheath. Use red - yellow DC wire if you can get it, save the white black for AC.