Prater

Started the TLC on the 357 today. Props are off to Throttle-Up for inspection, removed the old carpet in the cabin, and started a cleanup of the bilge. I was very carefull keeping the water of the inverter in the bilge but must have got some near or in the unit. I plugged the power back to the boat and walked out and touched the outdrive. It nearly nocked me on the ground. I unplugged the boat and am a little afraid to plug it back in. Any suggestions? Keep me alive guys...

RonS

I had the same thing happen to me, it's not your boat it's your extension cord, I switched cords and everything was OK

FormulaM2Formula

WARNING: Long post.

It could be a bad extension cord is part of the problem. But, it sounds like the neutral (white wire) and the green ground wire might be connected to gether on the boat somewhere which is NOT the way it should be when connected to shore power. Since the boat will have the AC ground connected to the DC ground (usually in the power panel), the result is that anyone that touches any grounded piece of equipment (like a drive) while standing on earth has created another circuit to pass current back to ground. If the extension cord has a high resistance in the white wire, then path through the drive into a person to earth will make a better path and it'll shock you. If the white wire were to become open it could electrocute you.

On a boat with the white and green wires not connected, a bad white wire in the extension cord would not cause you to get shocked by touching the drive because there is no path for the hot wire to get to the ground unless there is another fault. Even with an open circuit in both the green and white wires in the extension cord, there has to be an electrical fault and/or the white and green connected together in order to get a shock like you describe.

It could be that the white wire and green wire are connected somewhere. It could be in the panel, it could be in an appliance, it could be in an outlet. It doesn't matter where it is, it's unsafe.

It could be that an AC appliance has developed a fault which results in the neutral being in contact with the green wire. It could be than an appliance has a the neutral and green wires both connected to the frame. Also, unsafe.

The inverter may be the source of the problem. When an inverter is turning DC to AC, it will internally connect the green and white wire together, because it is the source of the power. (Also a generator will connect the white and green together) But, when the inverter senses AC power on the input, it should automatically disconnect the white from the green since it should only be connected on shore. (When a generator is switched out of the circuit, all 3 conductors are switched out on a boat to prevent the green/white connection.)

There are other ways the drives could be "Hot" but, they are somewhat unlikely. Like not having the DC and AC grounds connected, and/or then having the hot AC wire contacting the DC ground. Not likely.

It could be that the inverter flipped its wig after getting wet and malfunctioned, but I wouldn't want to bet my life on it.

The first thing I'd check is to see if the white wire and grounds are connected on the boat. To do this, you will have to disconnect shore power. Turn the inverter off preferably by removing the battery power from it so it can't shock you. At the power panel, turn off the main AC breaker. Open the panel and put the test leads from digital ohm meter (make sure it is the ohm setting not volts) on the green and white wires. It should show an open circuit, or blink overload or something. If the ohm reading drops to anything under a Megaohm, it is likely connected at an outlet, an appliance, or some electrical fault has developed in the wiring. Then you just have to find out where. Because only the black wire is switched for each individual appliance, the connection between white and ground can be anywhere.

If the white to green resistance shows open, then test the resistance (ohms again) between the AC and DC ground in the power panel. This reading should be close to zero, or no more than single digit ohms. If the resistance is very high, or showing an open circuit, then the DC and AC grounds need to be connected together. My Formula has these connected in the power panel with a wire between the AC and DC ground buss bars.

Next, w/ main breaker still off and all appliance breakers off, test ohms between the black and green wire. Should be open. Individually switch one appliance on at a time, (power still off at main panel AC breaker) and test black to green.) All should be open circuit. If any of them read a low ohm reading, then it is likely that something is amiss, but I wouldn't expect this this to tell me anything unless I already found a problem with low ohms between white and green, and this test won't always identify the appliance because the ohm meter will use DC volts that might not pass through depending on the appliance.

If all the above checks come out the right way, then it check the ohms between white and green on the input side of teh main AC panel breaker (making sure inverter DC power is disconnected, and shore power disconnected) with the breaker off. This should also be open. If it isn't open, check the manual, check the inverter install to make sure white and green weren't connected at the inverter. The inverter should only close the circuit on green and white when inverting, and should be open when not inverting or charging from shore power.

It could also be that the inverter is fine and the install is fine even if the white/green resistance on input side of panel AC breaker is not showing open. This would indicate a fault between neutral and ground in the input harness or a wrong wiring possibly where shore power comes in.

Check the shore power plug by turning off the shore power input breaker if you have one that is separate from the AC panel breaker, and then test resistance between shore power input ground input and the other two terminals. Both readings should be open circuit.

Sorry for the novel, but it is worth it if it helps you find the problem and it is too dangerous to not check it out. If you don't feel comfortable doing this, or are not sure that you are doing the right thing, find someone to help you check it out. It is not safe the way it is.

If you want to talk about it, PM me and I'll give you my phone #.

Good luck. Also, test your ohm meter first before doing all this work. Open and short the test leads is all you need.

Garrett

Prater

Garrett,

Thanks for the info. So far I think I shorted the invertor with water while cleaning. The voltage read 0.6 with the boat on shore power at the outdrive yesterday. I will check it again today if possible(rain). Then off for a couple of weeks on business. I get a reading of 0 when the shore power is unplugged. I am keeping it unplugged until I find the problem.

Ron,

Thanks but trying a new cable did not work, still detected voltage. It is on a 30AMP shore power cable.

Prater

No voltage today. I must have gotten water where it was not supposed to be.