All ground wires burnt

[yoeman]

Negative wires to all gauges burned

Not
a great situation but we recently replaced my 5.7 1975 engine and did not modifiy any wires except one wire that runs from the positive post to the alternator. This wire was very corroded and actually was showing signs that it was burned or corroded through.
New starter installed with original external solinoid
When we turned the battery on the ignition to start all ground wires to my gauges burnt up
Now we are stumped because the Tollycraft never had any issues prior to me pulling the engine Very sad after all the work.
Could a bad alternator or voltage regulator cause a massive fault like this?
Thanks
We have looked at all battery wires solinoid and starter wires and they look correct

 

[yoeman]

Any ideas on how all ground wires to my gauges on my helm could burn after we replaced my 350 engine
Would a bad alternator or regulator be suspect?
Battery wires all look correct

 

[ksanders]

In order for you to actually burn up wires it takes a hell of allot of current.

Almost guaranteed, what you did is to apply 12 volts, directly coupled to ground through the wires. You'll eventually figure it out, but you hooked up those wires to 12 volts somewhere.

 

[yoeman]

In order for you to actually burn up wires it takes a hell of allot of current. Almost guaranteed, what you did is to apply 12 volts, directly coupled to ground through the wires. You'll eventually figure it out, but you hooked up those wires to 12 volts somewhere.[/QUOTE
The starter solinoid and alternator wires were all removed and pictures taken but like I posted I did replace a broken or burned alternator charging wire We disconnected the alternator and regulator and it looks like the issue is in that area
I was thinking the bolt on the alternator may have twisted direct shorting the alternator to positive charge and passing the positive true the block
Lost really and such a shame because lots of nice items may be fried now

 

[tpbrady]

Reversed polarity? With key off and battery switch on there should be no power to gauges. Since the ground side is burned it shows high current coming from ground. My educated guess at this point.

Tom

 

[yoeman]

Reversed polarity? With key off and battery switch on there should be no power to gauges. Since the ground side is burned it shows high current coming from ground. My educated guess at this point. Tom[/QUOTE
I'm digging to find out how the positive power can go through the ground form the engine
To the gauges
Im going digging again tomorrow First thing will be getting the alternator tested Long shot
Thanks

 

[jstauffer]

Did your new engine get grounded after replacing it?

 

[yoeman]

Did your new engine get grounded after replacing it?

Can you clarify It has all grounds connected to the bell housing

 

[Aquabelle]

Whatever the initial fault, your ground wire dimensions are under-sized: at least one needs to be big enough to carry all return current

 

[psneeld]

Whatever the initial fault, your ground wire dimensions are under-sized: at least one needs to be big enough to carry all return current

Not if accidently hooked to the positive side ..... no telling WHAT is carrying what.

Many grounds are just jumpered in the gauge area....so small is sometimes hooked to large....granted not the best but common practice.

 

[rwidman]

Your ground wires burned because too much current was passing through them. Not being there and not having done the work, it's impossible to say why.

You will have to go back and check your work or have someone check it for you. Something is connected wrong.

Repair 101 - If it worked before you did some work on it and it doesn't work after, it's probably something you did.

 

[yoeman]

Your ground wires burned because too much current was passing through them. Not being there and not having done the work, it's impossible to say why. You will have to go back and check your work or have someone check it for you. Something is connected wrong. Repair 101 - If it worked before you did some work on it and it doesn't work after, it's probably something you did.

I do understand that but I was hoping for a response that it could be the solenoid connections or something in the alternator
They burned because I've hook up or crimped a positive wire and it's going to ground
I'm guessing the instrument ground wires burned is because they were the smaller ones
I do know it was done by me. I'm thinking solenoid because that goes back to the ignition switch which powers the gauges when selected on
Thanks

 

[jstauffer]

Did the gauge wires burn when the ignition switch was just turned to the on position or when it was turned to the start position? It would seem unlikely that by the switch just being in the on position there would be enough current supply capability in the positive supply wires to allow all gauge ground wires to burn up. However, if they burned up when in the start position there would then indeed be enough current capability via the positive starter cable. That is why I thought maybe the engine (bell housing) wires did not get connected.

 

[yoeman]

Interesting We did connect the grounds to the bell housing but I think you are turning me towards the wire that goes from the ignition switch to the solenoid
I can't see any other way for the current to get to the panel other then via the switch and I can only see one positive of the starter solenoid
I'll post back when I find it
Thanks

 

[yoeman]

Interesting We did connect the grounds to the bell housing but I think you are turning me towards the wire that goes from the ignition switch to the solenoid I can't see any other way for the current to get to the panel other then via the switch and I can only see one positive of the starter solenoid I'll post back when I find it Thanks[/QUOTE
Thanks for all the help

 

[DavidM]

The typical alarm setup has 12V power being supplied FROM A FUSE OR BREAKER to the alarm device and then to multiple sensor switches for oil pressure, water temperature, etc. When one of those sensors is closed, like at startup with no oil pressure it completes the circuit to ground and the alarm sounds until the engine starts, builds up pressure and opens the switch/sensor.

So one theory is that the 12V source was not fused (not uncommon) and somehow 12V was connected to the wrong side of the alarm. When you switched the batteries on it supplied 12V directly to the oil pressure switch which was closed to ground and it pulled high current because the alarm wasn't in the circuit to limit it and the wire burned through.

The same thing can happen to the idiot light for the alternator. If it was wired wrong and was not fused it could burn the wire.

Make sense?

David

 

[yoeman]

wires

The typical alarm setup has 12V power being supplied FROM A FUSE OR BREAKER to the alarm device and then to multiple sensor switches for oil pressure, water temperature, etc. When one of those sensors is closed, like at startup with no oil pressure it completes the circuit to ground and the alarm sounds until the engine starts, builds up pressure and opens the switch/sensor.

So one theory is that the 12V source was not fused (not uncommon) and somehow 12V was connected to the wrong side of the alarm. When you switched the batteries on it supplied 12V directly to the oil pressure switch which was closed to ground and it pulled high current because the alarm wasn't in the circuit to limit it and the wire burned through.

The same thing can happen to the idiot light for the alternator. If it was wired wrong and was not fused it could burn the wire.

Make sense?

David

I changed the alternator and voltage regulator because a marine/auto electric shop advised me that if the regulator failed to ground it could cook the small ground wires. Im not sure but it seems the replacement works and no more smoke show. Its lucky that the smaller wires cooked but the gauges didnt get fried.
Im a little concerned as the voltage is as high as 15.5 then drops back to 14 at idle. I didnt test the battery but it was on a trickle charge. Might have another issue
Thanks for the help

 

[tpbrady]

Interesting description from the electric shop. I wonder what the failure mode was for the regulator. Because the grounds all burned, it indicates that the current originated on the ground side of the gauges, otherwise the fusing protecting the hot side of the gauges should have blown. In this case the small gauge ground wires acted like fuses. For that to happen battery voltage had to be shorted to ground in the regulator and the only path to ground from the regulator was through the gauge grounds.

Makes me want to look at a how the regulator is installed in my alternator setup since I use an external regulator. It also is prompting me to look at how the gauges are fused since I don't recall seeing any fuses on the hot side of the gauges. There should be only one since they all tied to the ignition switch.

Tom

 

[yoeman]

wires

Interesting description from the electric shop. I wonder what the failure mode was for the regulator. Because the grounds all burned, it indicates that the current originated on the ground side of the gauges, otherwise the fusing protecting the hot side of the gauges should have blown. In this case the small gauge ground wires acted like fuses. For that to happen battery voltage had to be shorted to ground in the regulator and the only path to ground from the regulator was through the gauge grounds.

Makes me want to look at a how the regulator is installed in my alternator setup since I use an external regulator. It also is prompting me to look at how the gauges are fused since I don't recall seeing any fuses on the hot side of the gauges. There should be only one since they all tied to the ignition switch.

Tom

Ive changed the regulator and had the alt tested so installed them but now the volt meter shows 14 volt charge at low idle the bounces around 16.5 to 16 at higher rpm so back to the drawing board Im hoping its just a bed regulator

 

[yoeman]

Burnt wires

The typical alarm setup has 12V power being supplied FROM A FUSE OR BREAKER to the alarm device and then to multiple sensor switches for oil pressure, water temperature, etc. When one of those sensors is closed, like at startup with no oil pressure it completes the circuit to ground and the alarm sounds until the engine starts, builds up pressure and opens the switch/sensor.

So one theory is that the 12V source was not fused (not uncommon) and somehow 12V was connected to the wrong side of the alarm. When you switched the batteries on it supplied 12V directly to the oil pressure switch which was closed to ground and it pulled high current because the alarm wasn't in the circuit to limit it and the wire burned through.

The same thing can happen to the idiot light for the alternator. If it was wired wrong and was not fused it could burn the wire.

Make sense?

David

Interesting thought because the boat has a couple of pressure sensors on the back of the engine and yet no alarms work on the boat I'm not sure this 1975 would have them but it could be I've hooked them up incorrectly
I'll post back

 

[jstauffer]

I think LarryM (in your other thread) is on the right track as far as the high voltage out of the alternator. Have you checked to see what the voltage is on the control voltage input to the regulator is (sometimes called the sensing input)? If that voltage is more than about a half of volt lower than your alternator output, then the regulator is going to tell the alternator to put out more. This low voltage on the control voltage input could be very low battery voltage, control voltage wire not conected or bad connection to the regulator and maybe even the incorrect resistance in your ballast wire that someone mentioned. I would take a reading on the control voltage wire and see what that is.

 

[psneeld]

maybe I missed something...how does slightly higher than normal voltage burn up wiring?

 

[yoeman]

High voltage

I think LarryM (in your other thread) is on the right track as far as the high voltage out of the alternator. Have you checked to see what the voltage is on the control voltage input to the regulator is (sometimes called the sensing input)? If that voltage is more than about a half of volt lower than your alternator output, then the regulator is going to tell the alternator to put out more. This low voltage on the control voltage input could be very low battery voltage, control voltage wire not conected or bad connection to the regulator and maybe even the incorrect resistance in your ballast wire that someone mentioned. I would take a reading on the control voltage wire and see what that is.

I spent to much time looking in the wrong area. I found a ground wire of a battery isolator so connected it to the starting battery and voltage dropped below 14 so I hope that is what was causing the issue
Would a battery isolator ground cause an overcharge?

 

[tpbrady]

An ungrounded battery isolator won't isolate or combine batteries in which the charge current won't get to the battery from the alternator. The sense wire from the regulator won't detect a voltage rise from the alternator so will keep ratcheting up alternator output until it does or it imolates itself. My guess is yes that could cause it.

Tom
Amateur Electrician

 

[C lectric]

I found a ground wire of a battery isolator so connected it to the starting battery and voltage dropped below 14 so I hope that is what was causing the issue
Would a battery isolator ground cause an overcharge?

_________________________________________________________________
____________________________________________________________

No. What you are thinking is an isolator ground is not a ground. Isolators do not have grounds like other equipment, motors, lights,electronics. That lead was a 12V pos. and connecting it to the battery fixed it
BECAUSE
the alter. regulator has a remote sensing lead that went to that battery. Without the connection the regulator was not sensing the battery voltage building so it jacked the alternator output voltage up to try to compensate.

Isolators use diodes to 'isolate' the batteries and prevent current backflow or draining of batteries unintentionally. They also cause a Vdrop of between 0.5 and 0.75 volts depending upon the diodes used. That sense lead is one way of compensating for the Vdrop of the isolator but of course, as happened to you, can cause trouble if all is not connected properly.

 

[yoeman]

An ungrounded battery isolator won't isolate or combine batteries in which the charge current won't get to the battery from the alternator. The sense wire from the regulator won't detect a voltage rise from the alternator so will keep ratcheting up alternator output until it does or it imolates itself. My guess is yes that could cause it.

Tom
Amateur Electrician

Sounds like my drama may be over

 

[yoeman]

I found a ground wire of a battery isolator so connected it to the starting battery and voltage dropped below 14 so I hope that is what was causing the issue
Would a battery isolator ground cause an overcharge?

________________________________________________________________
____________________________________________________________

No. What you are thinking is an isolator ground is not a ground. Isolators do not have grounds like other equipment, motors, lights,electronics. That lead was a 12V pos. and connecting it to the battery fixed it
BECAUSE
the alter. regulator has a remote sensing lead that went to that battery. Without the connection the regulator was not sensing the battery voltage building so it jacked the alternator output voltage up to try to compensate.

Isolators use diodes to 'isolate' the batteries and prevent current backflow or draining of batteries unintentionally. They also cause a Vdrop of between 0.5 and 0.75 volts depending upon the diodes used. That sense lead is one way of compensating for the Vdrop of the isolator but of course, as happened to you, can cause trouble if all is not connected properly.

I connected it to the negative post on the starting battery so are you saying it should be on the positive side
It was a black wire

 

[sunchaser]

I connected it to the negative post on the starting battery so are you saying it should be on the positive side
It was a black wire

Egads Might I suggest three things

1. Good insurance
2. A good marine electrician
3. No sleepovers until problem(s) rectified

 

[C lectric]

Holy Shimblefinny.
I'm going to suggest that you confirm very carefully where that wire was originally connected , the other end, when you first found it. If it truly was connected to a BATTERY ISOLATOR at the one end then the other end should go to the battery positive.

BUT BE ABSOLUTELY SURE because if you and I are wrong you could have serious trouble.

You could end up with 24V the way it is.

I have seen to darn many boats wired with whatever is handy and positive and negative wires improperly identified. Maybe the colour code tape fell off. Unfortunately black is ubiquitous for battery cable and often was the only choice so had to be colour coded. Should be done at BOTH ends.

The most recent, a friends boat was done like this and has a rats nest of connections at the batteries and during a recent battery change a + wire got misconnected and blew some gear from the 24V. All from no marking or coding. I'll try help him when I get home.

Disconnect it from the battery you just connected it to. Use a Vmeter to check the lead to ground. There should be no voltage. Then start the engine with the wire securely out of the way. If it then goes to 12 or so volts it is a positive wire, not negative. Just be sure the originally connected end is attached to the ISOLATOR output terminal.

AND THEN MARK IT with red tape and cover that with clear heat shrink tube so it doesn't come off OR of course Red heat shrink tubing. Assuming of course I'm right this time.

If at this point you are not positive then disconnect that wire, STOP and call someone in and get help. Unfortunately , over the net like this things can be too easily be missed or misunderstood with disastrous results.

 

[yoeman]

I did go back over the setup and found the 1 positive wire went to the isolator from start battery 1 and positive wire 2 to isolator from start battery 2 the black small wire coming from the bottom of my isolator went to battery 1 ground so all good
My issues is that the alternator from port engine charges the house bank 8 6 volts while the starboard charges the 2 start battery's that have the isolator
The helm gauges show voltages as high as 16 volts in cruise and low idle around 13 volt My meter tested volts at 14.7 at the start battery's
Is this a big concern ? My battery's are almost 6 years old but the start battery's test ok I just added water to all house battery but did not test them yet
I do leave the a/c chargers on full time so they should be fully charged
Thanks for all the help