120 volt lighting - Electrocution issue?

[GrumpyOldGuy]

If you think about a DC / battery setup, the electricity wants to complete a path of least resistance between the 2 battery terminals. The battery is pretty much isolated from the rest of the world. It is pretty difficult to get your heart in the middle of this short and direct path, so they are considered safe.

With AC, one side is always connected to ground (at your breaker box). So if you have a short (or insulation fault) anyplace, it will try to use the ground as a return circuit. That actual path to ground is impossible to predict and your body may or may not be part of the path. You are basically relying on the GFI or a good safety ground connection to protect you.

If you are using AC, make absolutely sure the receptacle you are plugged into is grounded and wired correctly (many are not). Also make sure you have a ground wire run and it is exposed to the water so if the GFI fails, the electricity flows directly to the ground wire rather than through you to the ground.

 

[bvanant]

My understanding, and I'm not sure that I'd like to bet my life on my understanding, is that salt water is more conductive than the human body and thus electricity is unlikely to hurt you in the ocean, but that the opposite is the case in many "fresh water" bodies.

It is certainly true that the ocean is much more (like 4x) salty and thus conductive than your body, that doesn't mean it is impossible to get electrocuted in the ocean. If you are totally isolated from touching anything, I would suspect that you are probably safe, but if you are touching a ground (like the dock) then I think you might be in trouble. It doesn't take much voltage or current to ruin your whole day.
Bill

 

[Thalassamania]

Again. my poor understanding of the issue is that the electricity would flow through the water to the pier preferentially.

 

[LABRADORCOASTER]

Evening Gentlemen,

I used the 120 v. lighting again last Friday, in 30' of water, got the video, pics etc. for my inspection.

The 2 lights worked fine, no leaks, but I hear ya.

Now that i have the winter coming, ie: time. I will retire the system and change over to 12 volt, All I have to do is remove the bulb system and find an alternative 12 volt bulb. I found some small LED's that might work, and I plan to ''test'' a 12 v. halogen head light.

I appreciate the discussion, thanks