bad wiring

[Alan Wheeler]

Well I got the "shock" of my life today. Not literaly, but more in the shock of what could have happend. Lets step back a year. When we purchased the boat, the wiring was one thing I was going to upgrade. Whomever was responsible for the mess needs to be keel hauled. You could see the original wiring was well laid out, but the after years meant many extras where run and nothing kept tidy. So in present time, we have this birds nest of a mess behind the switch board. This is the 12V side by the way. Have already upgraded the 230V shore power supply panel and wiring. That one was at least tidy, but so out of date, it wouldn't pass current inspection requirements. But back to the 12V side, it was one of those jobs on my list, but as everything worked, it was down the list a bit.
So today, I went down to the boat to check on her, and I notice no digital readouts working on the switchboard. Hmmm, strange, we have no battery power on the board? I thought. I opened up the panel and was shocked to see a mess of burn't out wiring. What the!?!?!How the?!?!?!?! How on earth didn't the thing catch fire. Man was that lucky. So I now have a big job of rewiring ahead.
I was wondering, is anyone interested in me doing a wee log here, with some pictures of the upgrade as I do it and how I do it. Would it be of help to anyone? or just a bore.

[GordMay]

ABSOLUTELY - love to read about & see the re-wire job.!
Gord

[Wahoo Sails]

Wheels,
I for one, would like to see how it's done in your part of the world. Your story reminds me of a complete re-wire job I did about 7 years ago. The owner of an Islander 37' pilot house, told me that he thought there was something wrong with his wiring, and would I have a look? When I pulled the master panel, virtually all of the insulation had been burned from all the wires in sight ... and where they passed through a plywood bulkhead, the wood was badly scorched. The owner was damn lucky it didn't catch fire. As it turned out, the bilge blower was poorly located right at the transom, and had corroded a bit, and blown it's fuse. Apparently someone had replaced the fuse with a higher amperage one and when that one blew, yet a higher amperage one was put in. When I pried the melted plastic fuse holder open, there was a 35 amp fuse in it! The rest of the wiring was in deplorable shape ... little bits of wire (off all types and gauges) spliced together by twisting the wires together, then covered with masking tape. I refused to do ANY work on the boat unless I replaced ALL the wiring ... which happily, the owner agreed to.
People certainly get some funny ideas about what is acceptable in wiring. Looked at the backside of a master panel in a large trawler once, must have been 100+ wires there, and each and every one of them was red!!!!! A little flag taped to each wire with a hand written code on it ... the owner showed me a notebook from the previous owner showing where each coded wire went ... problem was, the notes were pretty much illegible, and the ink had faded from many of the flags! Thankfully, the problem was quite easily found (a defective charger/inverter) but sure glad I didn't have to work on the rest of it!
Just bought a 36' sloop ourselves, from all outward apperances, it is wired OK ... but will be adding a lot of new items (starting with shore power) .. will gladly swap notes as I get into the project .. won't actually take posession of the vessel for another week or two.

Bob & Lynn

L S/V Eva Luna

[Alan Wheeler]

Cool, well this will be a piece by piece subject then. It will take a little while to compleate as money is an obsticle at the mo. Huh, nothing new.

Gord, what is the best way to do this? I figured that I would post ongoing updates under this thread, involving a detailed explanation of what why and how and post a relevant photo in the gallery at the same time. Does that sound OK?

And please anybody, I maybe a technician, but I am always open to somebody having a better idea. So if I am in the process of doing something and someone thinks it could be better another way, I am very open to suggestions. At least it could open a debate or an explanation as to why I approached an obsticle a certain way.

Well, later today, I will start the sarga off with a photo of the panel in it's current mess.

[Alan Wheeler]

And so it begins. If you jump across to the Photo gallery, you will see two photo's. The front of the DC supply panel and the insides of it. Looks kinda like road kill. Sorry for the first two picture being over there. I will load them on this forum next time, but I mistakenly took two high res photo's that won't fit here.

Anyways, you will see that the front panel say's 24V. It is actually a 12V system. Voltage wise, this is not an issue, but Current wise, it is a major one. The new wiring needs to be spec'd for 12V. This may have been over looked when first built. I haven't looked that far yet. You will also notice glass fuse holders. Actually if you look real close, you will see the odd circuit breaker, where I have replaced a few high demand and important circuits over from fuse to breaker. Fuses can have their place, But IMO not in high load areas. Plus it is a pain having to fish through a container to find a replacement and chances are, when you need that replacement, it will be dark and ruff and you need it like real urgent. Another downside to the glass fuse, is the current lost across the fuse. For an example, one high load circuit was the fridge. It draws 16A@12V and the initial fuse was 20A. Well the fuse was running so hot, you couldn't hold your finger on its holder. Replacement with a 32A fuse has reduced that heat, but it still isn't perfect and you can see the current required to blow that circuit is now very high and if there is heat, there must be loss and we all know loss is not acceptable in a supply system. So many more breakers are going to be fitted. I will stick with the original panel, as a new one is finacially out of the question for me at the mo.
On the the wiring mess....
The burn out is now hard to see. I chopped a lot of that wiring away, so as there were no further lightups. But you can make out a few if you look hard. A slight scorch mark is on the bottem timber of the panel. The brass Bussbar at top looks like it is original. Some of that wiring has been laid neater, but one big issue is the colours used. A mistake can be made here, with red wires connected to that negative bar. It may even be possible that that is what has caused my burnout problem. I had been removing a reconnecting about 6 wires to rout around the AC panels and maybe one of those red ones got around the wrong way. One certainly was damaged. So when it switched on, the thing it was supplying has died and shorted. Not sure yet, but all will eventualy be revealed.
Another dumb idea, was the DC supply line from the battery. If you look down to the right bottem corner, you will see a large black cable fitted onto a block and a couple or three smaller red ones coming off the bottem of the block. That block is the Current load cell for the panel meter. The two smaller Red wires are the main feed to the main circuit breaker on the battery islolator panel down in the engine room. There is a 100A breaker on the end of those. They probably wouldn't pass enough current to trip a 100A breaker, especially when that gauge wire has been run about 20ft in length. The big heavey black cable, only goes down to the battery selector switch below the panel. So have you thought of the real danger there??? yep, say your engine start is down and you can't turn over the big beast. So you switch in the house bank and then turn the key. A few hundred amps is going to be asked to flow down those red cables to start the engine. I did that once and it did start, but on paper, everything say's it shouldn't have. Infact, I should have had a nice heater system working
Now finally for this post, I am going to make a smaller circuit panel for up in the Pilot house. This will be a sub panel for the GPS, Radar, Sounder and Auto winch/chain counter and some Pilot house lights. At present all this is controled down stairs on theis big panel, which means I have to go down to turn something on or off. Not a problem with electronics as they have their own on/off controls, but a real pain for lights. But it also means I can have a breaker for each electronic instrument instead of one for all. At present, If one fails and shorts, you lose everything.
Hope that hasn't bored you all, will be a week or so before I can get back out to the boat, so keep lurking around.

[Strygaldwir]

Alan;

I have been going through much the same myself. The wiring in one hull was underwater for more than 3 days, so I took it all out. Instead of trying to wire on circuit at a time, I decided to understand what the manufacturer was doing and then replace it all. As you know, it is going to be expensive and time consuming.

As I am going through this, I decided to adopt certain conventions. All my AC cable is round, all DC circuits are flat cable. I use breakers to protect the wire, I use fuses to protect devices. I am using the flat auto type fuses on what I call nodes. I calculate total amperage and run to determine the gauge of the feeder line to a node, use the appropriate breaker to support the high/average amperage draw, then fused individual lines to the specific componets. Critical componets are individually wired. Things like water pressure pumps, water maker microwave circuit, refrigerator/freezer, mast light, bilge pumps are all individual circuits. But things like the sanitation systems and overhead lights are noded. I am trying to achieve consistency, safty, and ease of understanding.

I use Visio professional, and Excel to document everything I have done. I am also keeping notes on routing. I don't expect to sell the boat, but docs sure help the next person to figure out what you were doing. I some cases it helps you find out what the heck you were doing a year latter.

Good luck, I look forward to reading the updates.

[Alan Wheeler]

Good points strygaldwir. Here, our regulations state that all AC cable must be double insulated and of the voltage rating in use. We can not use rubber seathed cable. It is all PVC. Comonly called TPS(tough plastic sheathed) here. All AC is now three core P,N,E as even lighting can have metal housings. Anything metal MUST be earthed.
Something I intend to be doing, comes from my experiance in wiring A/V in large stadium complex's. In those situations, we have to be able to find and identify cables at any location. It maybe several hundred metres away to where the start or termination point of a cable is, so running back and forward to see what cable is what is impossible. Plus, it is all very well having documentation showing what was done. But what if it is ten years and several owners down the track or your documentation got wet and all the ink ran. So I will be showing identification practises. The other thing is fire routing. As the projects I managed were often involving EWIS(emergency warning and evac systems) they would have to work in the worst case scenario for a given period and also not be detrimental to the intergrity of each and adjoining fire zone. Now some of that would be overkill in our average cruiser. You may see it on commercial vessels, but not a small vessel. However, simpler but still important aspects in cable management will be shown. The biggest danger wiring presents to any vessel is fire. The cause of fire is usually just as what happend in my case. A conductor has become over heated for some reason, melted through it's insulation and then the insulation of the next one it was resting on and thus shorting it as well. The result started a chain reaction. Proper cable management removes as much of that possibility as can be, (without going over board with a solution).
Another aspect of boat wiring that is often different to other situations, is the circuit itself. Circuits on boats are called "floating circuits". This means they don't have a common earth as such. But this also means a heck of a lot of cable going every where, as both Positive and negative has to be run. However, there is a way to "short circuit" that a little and I will show how as well.

[GordMay]

Alan ~ You are off to a good start.

You’re right to be concerned about 24V to 12V conversion. Your currents would have doubled. I could fax you a handi 2 page wiring size chart, which also includes the 3% Voltage Drop calculation. Email me a fax number (Gord@BoatPro.zzn.com)

I don’t understand why a 32 A rated fuse should run cooler than a 20A fuse, which is appropriately sized for a 16A Fridge - unless you also changed to a larger frame size (fuse holder). BTW glass fuses also come in 25 A ratings (here in N/A).
Depending on the length, a #14AWG (2.08mm2) copper wire can be rated to 29 Amps*, whereas a 32 A fuse would only protect a #12AWG (3.31mm2) wire (rated 38A*).
These amperage ratings are from ABYC Table ‘IV’, which allows higher ampacities that the National Electrical Code (NEC). I always use the lower ampacities from the NEC, and apply 3% Voltage Drop (VD) calculation. Cable size is more often determined from VD calculations than simple ampacities (on DC systems).

I’d certainly replace any “Brass” bus bars with (Tin) Plated Copper bars.

Your Pilot House Sub-Panel is a good idea. Although you may calculate a total load of well under 30 Amps, I’d wire the Sub-Panel for much more - say 100Amps (at least #6AWG or 13.3mm2). You might install a smaller 30 - 40A Breaker at the main panel, use oversized 100A wire to Sub-Panel, then appropriately sized branch breakers & wire to each piece of equipment.
Have you seen my article “Ohm’s Law & Boats”?

Strygaldwir offers some good advice - although I’d use “Flat” 3-conductor cable (double insulated) for AC wiring, and either single-conductor wires or 2-conductor cables for DC. To further differentiate AC & DC wiring, I’d use YELLOW wires for DC Negative (rather than Black, which could be confused /w AC Hot). Whatever you choose, be consistent.

I wouldn’t save on wiring by utilizing (even appropriately sized) Common Negatives, except a very few specific instances.
..........

Regards,
Gord.............................................. ..................................................

[Strygaldwir]

Gord;

I think the flat cable does come in Double insulated. All the cable I am using is certified boat cable. The round type has a grey outer insulation, the flat style has white insulation. For the DC inner wire insulation I us Black and Red. For the AC inner isulation I use black, white and solid green. For DC grounding wire I have used a single insulated green with yellow stripe. As you said, it is all about consistency.

I also got one of those little lable makers. Great for indicating what a wire is/does. All AC is marked with White/Red lables. The DC lable is white/Black. Originally both DC and AC were put in the same terminal boxes. I have put the AC and DC in seperate terminal junction boxes. I have marked the covers of the boxes appropriately


The only difficulty is signal wire, I am trying to stay consistent with what the original equipment manufacture uses. Difficult at best.

Alan;

I am only using plastic boxes. Metal, just does not seem right. Yes, there are LOTS of cables and runs. It is VERY time consuming!!! All circuts are as you say floating.

All wiring is either breaker protected, or fused. Starting at 4 inches from the batteries and inverters. The breakers are the magnetic kind that supposidly trip on any shorts, excess heat, or over amperage conditions. Hopefully that minimizes the elecrical fire potiential.

The reason I use Visio to do the docs is so I can both print and store the docs on DVD for archival purposes. This gives me three chances of finding them when I need them. All lables are marked as above. I originally tried using those little cable disignators that look so cool. But, it was just not intuitive what A1, A2, B1, B2 was after trying to come back to it a week later. I now mark them with "Steaming Light", "Deck Light FWD", "Running lights" etc. the marker is great, once you type which lable you want, you can print it twice. Easy to do both ends. Cost me $40 at 'Office Max'.

I have not done to much to modifiy the routing of the wires. The original manufacture of the boat did a good job on that I believe. There are conduits for all the wiring (PVC tubing). They were all sealed when I pull the old wiring (silicone or expanding foam). Gromets for all equipment. If it were not for the fact that they were corroded by the swamping and inappropriately spliced by several prior owners, I would have left them alone. I did however rout AC and DC in seperate conduits, where possible (one place it was just not possible). I also did seperate routing for the signal and control cables. Where signals intersect current carrying I do so at right angles. Overkill, but good habits rarely hurt.

The thing I have yet to figure out is how to make it asethically pleasing. I am dying to see how you do it. My Blue Sea panels all have a negative and grounded bus on them. If I wire the negatives and grounds to the breaker bus it is very difficult to do nice wiring. I will almost assuridly install seperate busses. But function and substance first, then worry about form.

[Alan Wheeler]

I think between the three of us, we are going to end up with the most comprehensive article ever written about wiring
Gord, you have brought up something I haven't thought about. Wiring colour codeing difference between countries. It is as different as the way we spell the word Color/Colour
Here, our single phase AC is Red or brown=phase, Black or blue=Neutral, Green or Yellow with green stripe=earth. The use of white and black colours for phase duties is illegal here.
Three phase, each phase is White or Yellow, Blue, Red, with Black still neutral and Earth the same standard.
DC is Black=negative, Red=Positive.
Seeing as I am a Technician, I know most Ohms laws formulaes off by heart and conductor sizes. So I will try and remember to explain any issues with conductor choices as I go. While I wait for materials to be ordered and arrive, I need to sit down and draw up a schematic so as all that are reading this thread can follow.
Oh and about the fuses getting hot, the one reason why I detest glass type for high loadings, is not so much the heat disapated across the fuse, but the fact that such high current is asked to be conducted by a pressure contact on the ends of the fuse and it's conductor. Being in a corrosive environment, it doesn't take long for those contacts to build up resistance and create loss and thus heat. I have been concernerd with how detailed I get in explanations. One I don't want to bore people, Two I don't want to make it too complicated, three I am mindful of bandwidth. But maybe in just this type of technical instance, I need to be just a little more precise in explanation.

[GordMay]

Strygaldwir:
You’re right, both the flat and round “cables” are double-insulated. The outer sheath over both conductors, and the insulation on each conductor. I was merely “parroting” wheels description.
Descriptive labels are much preferred over just numbering wires - though I use both. I put numbers & descriptions at terminations, and just the numbers at access (pulling) points along the runs. I also seal the labels with clear heat shrink.
It sounds like you do an excellent (redundant) job of documenting your wiring.

Wheels (Alan):
Don’t save bandwidth - tell us all you have the time and patience for. I think anyone interested will have the attention span required to eagerly wade through the thread.
Your AC colour (color) code reflects the Euro’ standard, whereas North Americans use Black, White & Green. Do I presume correctly that you also use metric wire sizing, as opposed to American Wire Gauge (AWG)?

Gord

[Alan Wheeler]

Now when are yoiu guy's going to finally go witht he rest of the world and change totally to metric Yep we are metric. But I don have a coversion table somewhere here, so I will also try and remember to show both sizes.
Yes our colour code was originally Red and Black. Red being phase. Many years ago now, the change was made to include the Brown and Blue. As most of our imported electronics come from Asian manufacturers and we being a very small market, Asia started to manufacture one line that could be marketed in Europe and Pacific.
But I have always been interested to know Why you guy's use Black and White and why was the Black made the phase? Any idea's??

[Alan Wheeler]

PLEASE NOTE: I have had to load all pictures into the gallery, as even on the lowest setting, my file sizes are way to big for here.

Today I stripped out all the wiring from the switch board and removed the front control panel. The Wire that seemed to have started the whole calamity is still not identified. It goes up a wall somwhere and I still don't know what it does. I'll worry about that later. But as it melted, it cut its way through other cables and the worst case scenario had taken place. We were truely blessed, that we didn't lose the boat to fire. Some very large high amperage cables had been shorted and fried as well. The only thing that fused these, were the wires actually melting. Sheesh!
OK, on with the story.
So firstly, I am going to reuse most of the original wiring. The ones damaged are being replaced of course. But due to lack of both time and money (like us all) I am going to reuse what I have.
So as I said, the box has been cleaned right out and my first major job of that, was identifiying and nameing all the cables. I then changed the location and runs of several, starting with the main supply feed.
I will presume that those reading this now, have followed through the previouse posts. The battery isolator/combiner switch was fitted below the panel. This meant a very long run of main feed cables from Battery banks, some 4M or 12ft away. So if the banks were selected "combined", this meant a run of 8M/24ft of cable. Thats a lot of loss. To add to that, the main run for the house system, was on two very small feeds. Useing the House bank to engine start could have caused a major melt down. So I left the main engine bank feed, which is a 25mm2 cable and rewired it from the house bank. The selector switch will eventually go back in the engine room on the main circuit breaker/isolator panel. Seeing as I have 400AH of house and just a sniffel under 2000CCA of engine start, I doubt I will ever need to combine either, unless it is an emergency, in which case, access to the breaker panel in the engine room is no problem anyway.
I then added another Buss bar in the box. All the negative cables were run back into the box and terminated. It looks much tidy'er all ready.
Now as I have said, I am reuseing existing cabling. This does lead to one problem. I still have a liquorice allsorts of cable colours and most cable is not a marine grade (tinned) wire. So this is what I did. You will find pictures in the Gallery that will make this make more sense.
Firstly, Always make sure your wires are long enough. If running new stuff, don't be too stingey with length. It is always easier to shorten the wire, than extend it. The length allows you to dress the wire where it needs to run and to have plenty of length to create the termination.
I placed a sleeve of black heatshrink over each negative wire, so as 1: it could be identified as Negative and 2: it allows me to do the following.
Any wire that was plain copper, had the end of it tinned. To do this, you need a decent soldering iron. Heat the wire and allow the solder to flow down the tip of the wire and into the insulating jacket. Just a very light coating of solder. Never put a heavey coating of solder on any wire, when it is going to be held in place by a screw. Solder has no "spring" effect like copper. So if even the slightest tension of the terminal screw is lost, the connection will work lose.
After soldering, and while the wire is still very warm (not hot) from the soldering, put a small amount of glue from a hot glue gun on the end of the insulation and pull the heatshrink down just covering the bare wire. If the wire was still too hot, it will shrink the stuff before yuou get it to where you want. Now shrink it with the heat gun. Best way to shrink Heatshrink by the way. A hot air gun is the bees knees.
As the Heatshrink does such, the glue is squeezed out and seals the insulation. I do all wire terminations this way. I reckon it's the best way to do a wire to wire termination. It makes the termination compleately air and water tight and stops corrosion working back up the copper wire. The same for the terminations we are working with in this scenario. It means we can get away with plain copper wire. HOWEVER, should this be new wiring for you, make sure you start with Tinned wire. It is much easier than the hassle of what I have done today.
Identification is another important part. Most of the negatives will not be labled. All Positives will be. But one Negative was identified via a lable. This one was a common that went to another three negative feeds for the window wiper motors. The three motors have their negative feeds terminated behind a panel elsewhere in the boat. So following the wires from those, would have made any sense in the main panel. It was a good label to use as a demonstration of how to. I printed off the lable on my lable machine and placed it on the cable. A piece of clear heatshrink was then slid over the lable and shrunk. Be very careful not to over heat the shrink over the label itsself. Most of those lable machines use heat to print and the heat gun will turn the little message black.
I will stop here and go place some pictures in the gallery. Tommorrow I am back to start on the positive side of the panel.

[Alan Wheeler]

Next chapter. Making a termination in a screw locking termination device. Errr, well that means anything from a Buss bar to a strip connector or chocolate block connector to a plug/socket. Anything that uses a screw to lock the wire in place. I see this done so incorectly so many times, even buy the pros that should know better.
Strip about 1/2" to 3/4" of insulation off the copper wire. It's not really important the length, but it is important not to be too misely. Now take note of the way the copper strnds are spiraled. All multi-strand wire is twisted during manufacture.(well the stuff we play with anyway). Make sure you twist the wire in the same direction as it is naturally laid. Usually anti-clockwise, but who knows what you guy's do in the Northern Hemisphere where the world is spinning the wrong way
So hopefully you gathered from that explanation that you need to twist the wire some more than it's natural lay. This is just to hold it all together better. Now bend half of the twisted end back over itself. Too short??? then just cut a little more insulation off. Now you see why you don't want to scrimp in the first place. Now push the bent end into the terminal with the bent back piece of wire tip, faceing up against the screw. Incase that was confusing, just make sure the screw will tighten down into the bent back piece of wire and NOT the main wire. The reason for doing this is multi-fold. Firstly, the doubled area increases contact area in the connector. Secondly, the screw will always damage strands of wire as it locks down. So this means that the strands damaged are not the main conductor, but just this little bent back piece. And three, it creates a better bed for the screw to hold onto and it won't come lose with vibration. I have placed a photo in the gallery that will hopefully add another thousand words

[Strygaldwir]

I thought we here in the US were supposed to have positive securing devices on all our terminals. i.e. for all my connections I soldered/crimped ring terminals to the end of the wires. Actually what I did was as follows:

o crimped the wire to the terminal. To provide a mechanical connection

o Soldered the crimped connection. To provide an electrical connection. Used silver soldier.

o Put on electrical silicone. To protect from moisture.

o Heat shrink to provide insulation for the terminal end.

o Instead of butt connectors, I used ring connectors to connect all wires. Mostly this was used on things like sensors and devices that already had wires internally connected. The problem has been securing these connections in a terminal box. When they were a small number of connections, it has not been a problem. But the bilge pumps.... A challenge!

I have been using this technique on cars for years. Never had any issues with bad electrical connections. Even after 25 years! (Unitl recently still had my first car! VW bug, but that's another story). The marine environment is REALLY bad on electrical connections. If you ever get salt in any of the connections, you WILL have corrosion and eventual failure. (Salt is Hydroscopic, it will attract moisture in the air. Once you have saltwater, metal and an electrical connection, you will get galvanic corrosion if there are different type of metals involved. ) Worse yet, the connection introduces additional circuit resistance. This could result in burn out devices at worse, (okay maybe a fire is worse) or difficult to diagnois electrical gremlins.

Any way. Just my way.

Keith