Fireworks display ... on my boat!

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S

Scott

Last night I was attempting to fish a wire thru a bulkhead and past the electrical panel to get to the battery. It's the yellow wire from the new stereo I'm installing that wants to be connected directly to the battery for some memory function. I had the selector switch on because I had been "testing" some terminals on the panel. So when a stray red positive lead brushed up against the negative bar, the fireworks started and gave me quite a surprise! Fortunately, I was right next to the selector switch and shut it off before a fire started! The smoke was a little scary, though, and I was a little shaken up. As it turns out, it appears to be a 14 AWG positive lead that ran from a post on the selector switch directly to the battery display guage on my electrical panel. The end of the lead was the female end of a spade connector and in the tangle of wires I hadn't noticed that it was disconnected. The insulation of the wire was fried for the entire length. At first, I was puzzled because I couldn't figure out where this lead had come from until I noticed the empty spade connectors at the display guage. It was scary to realize that this may have been disconnected for a while! After I removed the wire, I turned the selector switch on and all was well. I am a little worried because after the excitement and the clean-up, I haven't inspected the wires that were in the same vicinity to see if there was any insulation damage to any of them. The negative lead, where the short occurred, does not appear to have any damage. I always turn the selector switch off when I leave the boat. I am a beginner at electrical work, but reading and learning with some new experiences. My panel has fuses (8 fuses and 8 switches), and the power lead ties to the first fuse in the series. There is no fuse at the battery display guage. The leads from the switches go across to a positive bar, just above the negative bar with all the various wires being attached with ring terminals at the bars. The terminals at the switches are spade. I imaging this is typical for older boats. Trying to get these wires organized neatly is going to be a job and a half, but I'm more nervous about not doing it now than I was before. Now it looks like a priority. Should I be worried about any leads that were in proximity to the fried lead?
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Yes! turn off your battery, and check every wire and every connection.

Don't be afraid to pull on the wire a little. Your statement that there was an empty spade terminal and a bare wire end indicates poor crimping. A properly crimped connector will hold onto the wire and the wire will break outside of the crimp. Just be very glad that you weren't working in a 200 amp breaker panel connected to the commercial power grid. I have worked with electricity for fifty years and I am still afraid when I open the breaker panel in an older home. I have taken the covers off boxes and had wire nuts fall out. I consider that almost the same as raking leaves and finding an unexploded artillery round.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Prase the Lord

Sounds like you dodged the bullet. Unless the wire was actually touchng the one that cought fire I would say it should be OK. The only way to really be sure is to eyeball check them all. It should be pretty clear if they got damaged. I find that a strong light is very helpfull in these cases. Seems like all my wiring is back in a dark hole. A strong light makes any damaged wire pretty easy to ID. I ALWAYS take the ground cable off the batteries when I work on DC circuts and make sure the shore power cable is disconnected. If you have an auto start genset you want to disable and disconnect that one too. Once those two/three are secured you really can't have any fireworks till you reconnect them. You will be able to tell if there is a DC problem right off the bat when the ground terminal sparks heavily when you reconnect it. I've, on occasion, short cut the procedure when working on DC circuts but you really never want to do that when dealing with 120 volt AC. It has absolutly no sense of humor and will kill you (or someone else like a swimmer in the water) dead. You might want to think about having a mate around or telling a friend what you are up to also. Hate to hear you lay in the boat for a week before someone noticed the smell.
 
Feb 26, 2004
23,348
Catalina 34 224 Maple Bay, BC, Canada
Scott, you got a good start by DIY

and all the rest is "downhill" - you've done more than most in having the compunction to open up your panel and do some wiring. All wiring is is a way to get electrons from Point A to Point B. As with everything electrical, the connections are extremely important. When we got our boat, the PO left a basic wiring diagram. What I did, over the course of a few months, was to trace an LABEL every single wire on the boat, starting with the panel. For instance, you talk about a "battery display gage" - ain't no such thing. It's got a REAL name, either a voltmeter or an ammeter. Which is it? That's important because of the way the wires run. As far as the basic question you asked, ONLY YOU can determine that, by looking and checking the wiring and connections. Ross' advice is well taken. So, as you're doing this, get yourself a big piece of paper and some tape and start drawing and labeling the wires. After a short time you'll begin to understand what's there and how it all works together. I knew nothing about boat electrical systems when we bought Aquavite in 1998, but I spent some "quality time" behind the panel figuring it out. Good luck, and anything else more specific, we're here for you.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
3M makes a tape kit of colored tapes or numbered tapes

ten small spools in a little carrier. You can either color code or number your wires and on the inside of the cover paste a sheet and write everything down. When you are sure that you have recorded everthing correctly varnish the list.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
link to marking tapes

It is a very long link.
 
S

Scott

Voltmeter, Stu ....

You're right, it helps to know the right language! It tells me the battery voltage when I switch it on. A few years ago, I started by getting a copy of Boat Electrics Simplified. This helped to guide me when I did some basic re-wiring for all the components on my mast. I've also replaced some battery cables that looked like they needed replacing. I bought a different selector switch which I haven't installed yet, but I think I will do it this weekend. Instead of the basic 1-All-2 selector switch, I have a newer one that simply has position "1" which energizes and isolates both house and starting batteries and position "combined" which does just that. Ross, I just submitted my permit package for finishing my basement. I've already had a subpanel installed in the basement by an electrician. But now I'm doing all the wiring. I drew the plan for all the wiring. This will be an adventure! ;) Bill, good advise about disconnecting the grounds ... I rarely have AC power on the boat as I am on a mooring (or a slip now, with no shore power).
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
yea Scott

i included AC cause most have inverters and messing around behind the panel with the shore power disconnected and the inverter running can be a situation you don't want to get into. Some inverters have such big DC wires that they have to be directly connected to the bateries. Disconnecting the ground insures that the inverter is powered down.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Scott, when you apply those wire nuts

really crank down on them. They are stronger than you are, so don't be afraid of breaking them.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Wire nuts????

Ross, please don't tell me you use wire nuts on your boat! With that said, I've heard that you get all kinds of corrosion issues they wire nuts. What is your experience?
 
Feb 26, 2004
23,348
Catalina 34 224 Maple Bay, BC, Canada
Bill, I think they were BOTH

talking about houses/commercial. But I've heard the yellow wire nuts are "prettier" on boats than the black ones.:):):)
 
Feb 6, 2006
249
Hunter 23 Bay Shore, LI, NY
Red to port

Surely the wire nuts on the boat should be red to port, green to starboard, and yellow up the mast? ;D
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
They come in all sorts of colors

We should probably run this by the first mate before settling on just one color though. Got to get the "look and feel" right or pay the price.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Scott, said that he was going to wire his basement in his house

fercryinoutloud. Of course I don't use wire nuts on a boat. I have seen boat wire twisted together and taped with masking tape. Not on my boat however.
 
S

Scott

No wire nuts on our boat!

Only right wing nuts! ;D Ross, I twist those things so tight I leave skin. I like home improvement projects. My biggest problem is finishing them. I get them started and find that finishing is too tedious for me ... so I get started on something new instead. You should see my outdoor projects! Since I seem to always be juggling 3 or 4 home improvement projects, some people ask me if I ever wanted to do it for a living. I explain that the problem with that is I am too slow and painstaking. I can spend a Saturday afternoon wiring a 3-way switch. *o Good one Bob V, that looks familiar.
 
D

DPatrick

Tracing Wires

I learned something that might be of help when you go tracing down those wires. Take a small wire tie, preferably a bright color, and slip it over the wire in question, but leave some slack in it. Cut off the excess and slide the wire on down to wherever it may go. That way you know that you are always following the same wire. I bet you were wide awake after the smoke cleared.
 
D

DPatrick

Two Good Books on boat wiring

Two books that I am looking for but have yet to acquire: Boatowners Mechanical and Electrical Manual - Nigel Calder Boatowners Illustrated Handbook of Wiring - Charlie Wing These books,I understand, have a lot of information including ABYC wiring standards.
 
Jun 2, 2004
252
hunter 260 Ruedi Res.
BobV, I love it

Do you know why the British drink warm beer? They own Lucas refrigerators.
 
Dec 27, 2005
500
Hunter 36 Chicago
At least you didn't do like an electrical apprentice

we left alone for a few minutes while hooking up a 240 volt DC bank for an uninterruptable power supply. After hooking up the 2 banks of batteries (this was probably equivalent to several thousand available amps at 240 volts), he decided to test the circuit by touching the positive and negative leads together like he was checking a car battery. Well, you can imagine what happened next - there was an explosion of molten lead. Luckily he wasn't burned too badly but he was pretty shaken up - he denied he had done anything wrong - but we all knew what happen when we saw all the molten lead and smelled the unmistakeable smell of burning insulation.
 

RAD

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Jun 3, 2004
2,330
Catalina 30 Bay Shore, N.Y.
No welding in the bilge!

12 volts DC or 120 volts AC is dangerous stuff and being in the electric buiness for over 30 years I've been there and done that and seen some pretty wild stuff that to this day makes me wonder why there wasn't a fire sooner and having an understanding of the National Electric Code I know why its important to follow it. The same goes for wiring on a boat as per ABYC standards cause 12 volts will start fires too, a lot of people think "its only 12 volts" As far as wire nuts on a boat are ok in the tool box for a quick repair till you get an inline crimp (I'm gulity of letting it go for a whole season and I have the crimps and a pro tool on board :eek: )
 
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