Shocking experience

[Galvez83]

Guys i am not an electrician by any means so i ask this forum for guidance as to how and why i feel an electric current when i touch the gimbal housing or any of its components. Long story short i installed a new engine and was installing the trim cylinders and outdrive when i leaned on the bell housing i felt tingling sensation. I then touched another part of the bell and gimball housing and then again i felt the tingling. I could tell it was an electric current. Any ideas as to how and why this could be happening?

 

[Scott Danforth]

You have something wired wrong

 

[ggc]

I would do this:

Use a voltmeter and measure the voltage on the gimbal to ground. Is it 12 volts or some other voltage. If 12 volts you have a misconnection or fault of a hot lead.

Check to see that the engine block and drive unit are grounded properly to the negative terminal.

Start pulling fuses or turn circuit breakers off one at a time until the voltage on the gimbal goes away. That is the circuit to check.

There are a few circuits that are fused separately in line such as your bilge pump. You can disconnect the bilge pump lead at the battery or where it is connected to see if that is where the fault is.

 

[Galvez83]

Thanks guys i will double check everything tomorrow and report findings.

 

[Galvez83]

I would do this:

Use a voltmeter and measure the voltage on the gimbal to ground. Is it 12 volts or some other voltage. If 12 volts you have a misconnection or fault of a hot lead.

Check to see that the engine block and drive unit are grounded properly to the negative terminal.

Start pulling fuses or turn circuit breakers off one at a time until the voltage on the gimbal goes away. That is the circuit to check.

There are a few circuits that are fused separately in line such as your bilge pump. You can disconnect the bilge pump lead at the battery or where it is connected to see if that is where the fault is.

Tested engine to ground and i got 0 volts. Will test gimbal tomorrow. Also checked all my connections and all are solid, nothing loose or missing. From what i recall i was wet at the time due to rain shower and working on the trim cylinders. Both had their grounding strap disconnected.

 

[tpenfield]

Bonding wire, perhaps?

 

[poconojoe]

I'm guessing there is only 12v DC battery power on your boat, not 120v AC shore power. Correct?

 

[Galvez83]

At the time it was connected to shore power only to charge batteries. All other brakers off. Brakers that where on were shore power and battery charger.

 

[dingbat]

Just for giggles....... with the battery charger connected as before.....check between "earth" (ground you where standing when wet) and the negative terminal on the boat then between the gimbal/motor to "earth".

Very well could be a ground leak or stray current off a near by supply line or even the charger itself

 

[poconojoe]

I would disconnect the shore power and remove the charger to narrow down if it's coming from that or the 12v DC.

Agree that it sounds like a grounding issue or a loose or corroded negative somewhere.

 

[tpenfield]

My thinking is that if the boat was on shore power and you are feeling voltage at the gimbal./transom assembly, then it is AC voltage you are feeling not the 12v DC. Something is not right with the wiring.

 

[Galvez83]

Sorry no update as of yet. I have and still am, fighting my drive trying to install it and it has been fighting me for 2 days, binding or something. As of now still no update on electrical

 

[tpenfield]

that's OK . . . we will be here.

 

[ggc]

To get a shock you must touch two conductors, normally metal, that are at different voltage levels, whether AC or DC. What else are you touching besides the gimbal housing when you get this tingling? Is it the engine?

Do you feel the tingling if the AC power is not connected?

You determined that the engine is at ground potential. Did you also check for voltage between the gimbal housing and ground (negative battery terminal)

when you check for voltage, is your meter set to AC or DC voltage? I would check both AC and DC volts from gimbal housing to negative battery terminal with the AC power connected and disconnected.

 

[ta79pr]

Could it be shore power coming through the water, as if bad wiring from a dock outlet or light? I am no expert, but it is rare IMO to "feel" DC.

 

[ggc]

If there is leakage from the shore power into the water near the boat, the outdrive is in the water so anything connected to the outdrive, an ungrounded gimbal housing, could have that voltage waiting for a path to ground.

You could receive a shock if you touch the gimbal housing (if unbonded to ground) and another metal part with a path to the shore power system ground. If that is happening, you could prevent the tingling by bonding the outdrive and gimbal to ground, which it should be anyway.

But that does not solve the bigger problem, the shore power fault, if that is the source of the tingling which is the current flowing through your body to ground. AC is more likely to be felt than DC, and is much more dangerous. I boated in an area where drowning fatalities to swimmers resulted from shore power leakage current flowing through the water. That is why most marinas do not permit swimming.

If it appears that there may be leakage into the water, this should be reported to the marina checked out by a competent electrician. (There is a good article on this in the latest Boat US magazine by the way.)