Need Electrical help....getting a little shock!

sailingdog · Mar 20, 2009

The Green Wire is usually an 110 VAC ground. That shouldn't be connected to the engine at all. The ground wire on your DC panel should be either BLACK or YELLOW.

A wiring diagram or sketch of what you've got setup would really help. Disconnect the shore power cable and see if you still get a shock. If not, the shock is coming from the AC side of the boat, and really needs to be investigated, since it can kill you.

You shouldn't need to run a separate ground wire from the engine to the panel, since the engine should be grounded already, or at least you say it is.

brobins75 said:
I rewired my 86 hunter 40, and now I get a little shock when I hold on to a pole and touch something on my distribution panel. Its a ss support pole from the cabin top down to the bilge.

obviously something is wire wrong. I grounded the green wire from my panel to the engine block. is that right? also my dc is grounded to the engine.

I also noticed another shock. I was working near my hot water heater and got a shock when i touched 2 adjacent pieces of the unit. I can touch any part of the unit, but when i touch 2 places at the same time i get a shock. any ideas? I guess i need to take the cover off and examine the wiring. probably something touching inside.

I have an a/c charger onboard-40amp truecharge. it is hardwired to the panel. other than that, I have a/c outlets, refrigerator (just installed, so that isnt the problem), water heater, and thats about it.

Im on the hard and Im using an extension cord and adapter for 30amp shorepower. I have breakers at shorepower in, and on distribution panel. The ground is a big post connected to the engine with a/c & d/c ground attached.

thanks for your help. im trying to finish up and launch soon!

B

RanAweigh · Mar 20, 2009

You say you are using an extension cord and an adapter. From this I presume that you have this extension cord plugged into some outlet somewhere. You don't say if "on the hard" means a marina or your backyard. I would suggest the first thing to check is the polarity of the outlet then check the extension cord. An "outlet tester" from the hardware store or home center is a good source. IF at the source L1 and neutral are reversed you will get belted. If the ground conductor in the extension cord is interrupted you could get belted. The tester looks like this"

Ross · Mar 20, 2009

What does your volt meter say? Just because there is a three wire outlet on the marina side it doesn't mean it is properly wired. THIS IS A DANGEROUS CONDITION> BE VERY CAREFUL.

Mike B · Mar 20, 2009

Sounds like there's 110AC on your ground side. When you touch anything metal that happens to be tied into the ground then another ground source you're completing the circuit and feeling the shock. You're lucky you haven't been knocked on you butt or worse. It's only a matter of time before you happen across the right combination that will do that to you. As the others have recommended check your polarity all the way back to the power box on the dock. I'd make it a PRIORITY.

Mike B · Mar 20, 2009

In addition to checking for polarity issues I'd also check for any AC wiring that may have an exposed end or be chafed and touching bare metal.

Mike B · Mar 20, 2009

Here's a response from a web site to someone with similiar problem. You may find it helpful.

http://easyacdc.com/?cat=23

For boat wiring, the AC hot is black, AC neutral is white, and AC ground is green. The AC neutral and AC ground are connected at the source of power (usually a transformer on the dock) and are not connected at any point on the boat. In your house, the AC neutral and AC ground are connected together in your breaker box. Your shocking situation is more common in boats due to this lack of connection between the AC neutral and AC ground.
I would start at the AC distribution panel on your boat.
Carefully measure the voltage between you White Neutral buss and the Green Ground buss. If you measure 115 volts AC, your polarity is reversed someplace in the feed system (dock receptacle, cordset, adaptors, etc). If you measure close to 0 volts AC, you have something wired incorrectly in an outlet or appliance that is causing the reverse polarity situation

Mike B · Mar 20, 2009

PS I don't believe the lack of ground would cause your problem but the fact it's missing creates an additional safety factor. The ground is there to shunt any electricity from a short and thereby prevent someone getting shocked. Basically it's easier for the electricity to flow through the ground wire than you so you should feel nothing under normal circumstances. In your case the easiest path for it to flow through is you and you're getting a tingle. I suspect you're only getting a tingle because the objects you've touched so far don't make good grounds. If you were to touch a better ground source my bet is you'd get knocked on your butt or worse. Fix the ground on your cord first, check for polarity next. Don't forget to disconnect the cord before working on the ground lug.

r.w.landau · Mar 20, 2009

when you get this figured out...

Check all your zincs.
You have probably taxed them pretty good.
I do believe that it is your ac ground to the block.
The AC should be a totally seperate system with only a MARINE charger tied to the DC system.
Also verify that the GFI is wired correctly with the shore power side as the line side of the GFI.
Hope it is that easy!
r.w.landau

Bob Poff · Mar 20, 2009

1. Replace the plug on your extension cord so that you have a (safety) ground!

2. Get one of the testers shown above and plug it into one of your onboard outlets.
(My guess is that you're going to see a hot/neutral reversal)

3. Get that AC ground OFF of your engine.

Ross · Mar 20, 2009

It is probably worth the money to replace your recepticles with GFCI recepticles throughout your boat. But they won't work without a proper ground. Either that or install a 30 amp GFCI breaker in your service entry box.

Stu Jackson · Mar 20, 2009

First, get organized, and then get us some details for analysis

brobins75 said:
1. I rewired my 86 hunter 40, and now I get a little shock

2. obviously something is wire wrong. I grounded the green wire from my panel to the engine block. is that right? also my dc is grounded to the engine.

3. my hot water heater and got a shock when i touched 2 adjacent pieces of the unit. I can touch any part of the unit, but when i touch 2 places at the same time i get a shock. any ideas? I guess i need to take the cover off and examine the wiring. probably something touching inside.

4. I have an a/c charger onboard-40amp truecharge. it is hardwired to the panel. other than that, I have a/c outlets, refrigerator (just installed, so that isnt the problem), water heater, and thats about it.

5. Im on the hard and Im using an extension cord and adapter for 30amp shorepower. I have breakers at shorepower in, and on distribution panel. The ground is a big post connected to the engine with a/c & d/c ground attached.

Stop guessing.

1. A description of the extent of your "rewiring" would be helpful. AC side only or DC, too?

2. What encouraged you to "ground...the green wire from my panel to the engine block. is that right?" ? Was it there before you rewired, or did you put it in new? There is a long discussion in Calder's Boatowner's Manual for Mechanical & Electrical Systems" about that feature and I recall the conclusion is to ground the AC to the boat ground, i.e., the engine. However, many boats do not have this feature. If it IS the only thing you changed, when you rewired, try taking the AC ground off, and see what happens. If you haven't, read Calder's or others discussions about AC boat grounding. Do it at the same time or step-by-step one at a time with #5 below, i.e., add the ground for the extension cord and see if that fixes it, or leave the extension cord as it is and take the boat AC ground off the engine, or vice versa - try all combinations.

3. If you've done nothing to the hw heater, why would you suspect something wrong there? I wouldn't bother checking that wiring because the problem appears to be on the entire AC grounding, not just at the hw heater.

4. The charger should also not be an issue, same as #3.

5. Suggestions to check polarity have to do with the hot and neutral to ground. If there's no ground from your extension cord, the polarity test won't tell you anything you don't already know 'cuz there simply isn't any ground. If the hot and neutral are backwards, it won't affect working AC voltage, just safety if you touch the case of an ungrounded appliance, which may be what's happening with your hw heater.

What you need to do is METHODICALLY find out what's changed when you rewired, at the same time see if actually getting a ground on your extension cord eliminates the problem, and also do some more research on AC grounding.

If you added the AC ground to the engine and you do not have a shorepower ground, that could well be your problem.

Be methodical and safe.

r.w.landau · Mar 20, 2009

If the boat had proper gfi installation...

If you have one circuit, you only need one GFI. Two screws are for the line side and the other two screws are for the load side (all the other recepticals).
If the ground was not connected to the engine and the ground prong were broken off the shore plug, you would not be able to make the gfi work. You would not be able to set it with out proper wiring.
r.w.landau

Ross · Mar 20, 2009

Brobins, What are you using for a reference book? To attempt to rewire the boat as it was includes all of the mistakes that were wired into it in the past. get a good book, take a course at the community college. You are walking through a rickity house in the dark with a cell phone instead of a flash light. When you stick your foot down and don't find flooring and call someone to ask what is wrong, they will tell you it is a hole but they won't know anything beyond that because they ain't there. You must start reading about this subject just to learn about what you don't know or understand.

Mike B · Mar 20, 2009

Brobin, Ross is right referring you to an electrical manual for boats but if you do nothing else at this point make sure you fix the ground lug on the shore cord you're using. It's just down right dangerous not to have it properly wired.

Stu Jackson · Mar 20, 2009

brobins75 said:
Sweet. Im gonna try taking the a/c ground off the block. where do I ground it then? does it just go to the distribution panel main breaker? ...and I tried to rewire it the way it was originally, but I probably screwed up the ground. I did this over months and probably missed/forgot something.

What you don't seem to have done, unless you didn't mention it, was to start with a wiring diagram. Before you do anything, make one, or else you will simply continue to drag around and connect wiring WITHOUT any kind of a plan.

You take the AC ground off the block and connect it to nowhere. Leave the panel end connected, but simply disconnect the wire from the engine (ground). See what happens. But fix the lack of ground on the extension cord FIRST. This change is simply to check if you have a problem with the AC ground on the boat. My concern is that if you don't understand this, you have a loooong way to go. AC is dangerous if you don't understand it.

You need a book, not just any old simple "dumbed-down" boat wiring book, but Calder's Boatowner's Manual is very good. There are others, and probably more internet resources than earlier suggested, which are free. Google is a very good start, like: "A.C. boat wiring." Try it, see what you find.

I'd say good luck, but luck has NOTHING to do with it when it comes to electricity. You NEED to know what you're doin', and you seem to have a long way to go.

PLEASE, be very careful. The life you save may be your own and those of other people around you.