120 volt lighting - Electrocution issue?

[LABRADORCOASTER]

Made a newbie mistake and posted this earlier in the wrong forum.

I'm concerned about the possibility of getting ''shocked'' by using my home made lights. I have wired houses, 240, 120 & 12 volt stuff aboard boats, but I question what I have done here...

I built 3 underwater lights last year to allow me to do a wharf inspection. Needed to take pics/video etc.

(I live in a isolated region,, supplies are limited or a long time coming.)

I used 3'' ABS pipe, ordinary florescent bulbs and hooked it up with good quality new rubber coated 12/3 cord (75'long).

I put a GFCI plug on it.

It all worked fine, no leaks, good lighting etc, but I am wondering how stupid a move it is/was.

I am planning to do another inspection next week. Am I pushing my luck, are there other things I could do to make it safer.

OR, should I never use it again and take the time to modify it for 12 volt DC. LED's etc

I would appreciate your opinions.

thanks,

Wilson

 

[knowone]

:zap:The only problem I see is going a bit far and pulling out the plug.

However considering the length to which you have gone you may as well do some research and build some other diving illuminators as well or get a longer lead.

My light canisters are just 90 or 100mmPVC with glued or welded end caps and rubber hose clamped couplings for access, and some interesting heads 60 or 70metres last time I looked.

Bought two car halide globes and ballasts this week for 19 bucks that when I replace the gel 12s 4.5AH batteries with a smaller NiMiHi chinese pac with slight mods or new heads will fit perfectly but then who needs something so bright.:angel:

Photographers

 

[LABRADORCOASTER]

I was recently shopping at our ''local ''Canadain Tire'' I took a look at the 12 volt auto headlight bulbs, halogen I think. Don't know how hot they might get inside an ABS or PVC housing.

No harm in testing one, the cold water would perhaps help to cool the unit (s).

Yes, going farther than the length of the cord won't work. This is a job specific project where I need to lower the lighting down over the stern of the boat to inspect a wharf face, quite dark with little overhead light, poking the camera into holes etc.

thanks for responding.

 

[DeusVerto]

There are too many variables here to make a judgment call, but I do applaud your decision to protect the circuit with a GFCI.

It doesn't really take much of an electrical disturbance to stop your heart, especially if you already have any risk factors (age, weight, etc.).

From a practical standpoint, I think you're spot on with the cooling problem. Auto headlight bulbs might work, but keeping the temperature even across the glass envelope might be a challenge.

Let us know how this goes.

 

[joe8mofo]

I would say that even without the GFCI switch, there is more water in the body of water in which you are diving in and therefore more resistance, so the risk of a fatal shock would be low as the current would quickly be rendered inert by the vast volume of water. Think about lightening hitting the ocean directly above you while you are 40 ft down, the water would absorb the current and you would not be shocked by lightening unless you were on the surface and the lightening made direct contact with you. The risk of a fatality involving A/C household current is due in part to the small volume of water present in a bathtub/sink; so therefore the resistance present in a small area of water causes the current to also use a warm body (human) as a sink for the current, which could stop the heart.

The GFCI is designed for the purpose of cutting the current when a ground fault is detected within 25 ms. So worst case scenario your GFCI fails to cut the current, but in the event in which it does fail you are still swimming in a giant resistor.

 

[DeusVerto]

Joe, you are correct to point out that a bathtub is smaller than the ocean. Still, the path of current is uncertain. After further consideration, perhaps using low-voltage (US National Electrical Code considers anything under 24 volts to be "low") lamps might be a safer route.

 

[bvanant]

I would say that even without the GFCI switch, there is more water in the body of water in which you are diving in and therefore more resistance, so the risk of a fatal shock would be low as the current would quickly be rendered inert by the vast volume of water.

Sort of, but not really. The issue is that electricity just doesn't spread out like a wave when you drop a rock in a pond. The total volume of water has no bearing at all on the path the electricity will take. If you have your hand on the pier and the pier is grounded and there is a short near your other hand, your body MIGHT be the path of least resistance to ground (depending on a whole host of other variables). If your body is the path then you might die.
Why do you need lights powered by Hoover Dam, why not use battery lights (like cave divers) for the time you are in the water. Cannister lights will certainly be brighter than standard fluorescents. If you need wall powered lights, I would certainly go the 12 V route; this 120V 60Hz stuff can kill you.

Bill

 

[Maddog59]

Hi Guys,
Having worked in the professional film industry for over twenty years (most of that as an underwater gaffer) I can tell you that the current could be fatal if you happened to be hanging on to the wrong thing at the wrong time. 10ms CGFI's are the industry norm when working around water with high voltages and there is a wonderful product made in the USA called a Shock Block which is made for exactly this purpose.
I have to agree with bvanant on this, if your'e not set up properly to run high voltage stick with 36 volts or less.


Peter

 

[Maddog59]

Also guys it is possible to hire purpose built high voltage underwater lighting in the USA from PACE. They have a full range of lighting up to 8k HMI or 10k Tungsten!


Peter

 

[Thalassamania]

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.