Check your work

tmpsanity

Well-Known Member
Yet another fire. I saw on the newswire a dude in Pittsburgh set his attic on fire. Now he is in Police custody, his plants are fucked, (duh), and his house is fucked. This distresses me because electricity is not too complicated. Just do your research, do your math, let your area breathe so not to overload, and for the sake of your self; check your work.

Peace.
 

mogie

Well-Known Member
That is so very true. There are a lot of people that just don't respect electricity.

The Physical Effects of Electricity :
Electrocution or electrical shock occurs when an electric current I passes through the body. The amount of current passing through the body is determined by Ohm's Law:

I = E/R

I = Current Through the Body
E = Voltage across the body
R = Resistance of the Body

Body resistance is an important variable when considering electrocution. There is a wide variation in body resistance between people therefore the same voltage level may result in different effects. The typical human body has a hand to hand resistance (R) somewhere between 1,000 and 2,000 ohms. Babies, Children and some other people have less resistance.

The current is the controlling factor for Electrocution and Electrical Shock. The threshold for perception is about 100 microamps (0.0001 Amps). Also See Microshock Electrocution Hazards for currents less than 100 microamps. The National Electrical Code (NEC) considers 5 milliamps (0.005 Amps) to be a safe upper limit for children and adults hence the 5 milliamps GFI circuit breaker requirement for wet locations. The normal nervous system reaction to any perceptible electrical shock may cause a person to injure themselves or others, therefore the so called safe limit does not assure freedom from injury.

The more serious electrocution and shock hazards occur above the let go limits. 99% of the female population have an let go limit above 6 milliamps, with an average of 10.5 milliamps. 99% of the male population have an let go limit above 9 milliamps, with an average of 15.5 milliamps. Prolonged exposure to 60 Hz. currents greater than 18 milliamps, across the chest causes the diaphragm to contract which prevents breathing and causes the victim to suffocate. No data is available for females or children but suffocation is presumed to occur at a lower current level.

The frequency of the electrical current is as important as magnitude when evaluating electrocution and electrical shock injuries. Humans and animals are most susceptible to frequencies at 50 to 60 hertz. The internal frequency of the nerve signals controlling the heart is approximately 60 hertz. Ventricular fibrillation occurs when 60 hertz current from the electric shock interferes with the natural rhythm of the heart. The heart loses its ability to pump and death quickly follows. Ventricular fibrillation can occur at current levels as low as 30 milliamps for a two year old child and 60 milliamps for adults. Most adults will go into ventricular fibrillation at hand to hand currents below 100 milliamps (0.1 Amp).

Humans are able to withstand 10 times more current at DC and at 1000 hertz than at 50 or 60 Hz.. Electro-Surgical equipment operating above 100,000 Hertz pass high currents through the body with no effect on the heart or breathing of a patient. Do you think that Murphy's Law had anything to do with the American power line frequency being set at 60 Hertz and the frequency for the rest of the world being 50 hertz? All of the current limits referred to in the growfaq articles are based on power line frequencies of 50 or 60 hertz.

Electrocution may or may not leave physical evidence of the injury. The occurrence of burns or other skin damage is dependent upon the current density at the point where the current enters or leaves the body. Electrocutions occurring at 110 VAC seldom cause skin damage unless the point of contact is small or the victim has delicate skin. When higher voltages are involved, high currents pass through the body and there is greater likelihood that skin damage will occur. At higher voltages there are often, but not always entrance and exit wounds.


The painful truth :

This person lost the use of 3 fingers, which took over 7 months to heal.The thing that worries Overgrow / Growfaq is the fact that most people don't understand, or believe that most of the time this beast kill's and does so without warning.

Most Overgrow members wouldn't want to be put into an electric chair, but will climb into one willingly while wiring a room, opening a ballast, building their own ballasts or other devices, you name it.

Electricity can and will kill you if you don't respect it!





 

WillieNelson

Well-Known Member
As an electrican I can't agree more. Electrical safety is the most important part of your garden. Easy safe gaurds:

1. Ground every peice of metal in your grow room(hydro especially)
2. Use GFCI Receps, cords, or breakers to feed all loads. AFCI(arc fault circuit interupters are also a good idea)
3. Never use too small of wire. 15 amp breaker-14 gauge 20 amp breaker-12 gauge 30 amp breaker-10 gauge
4. Never work on anything live!!!
5. Loose connections are the cause of 90% of all electrical failure and many arcing fires. If you have wire nuts anywhere, tighten the hell out of them!
 

th3bigbad

Well-Known Member
and mogie "LOLed" your meat right before willie nelson said "4. Never work on anything live!!!"
lmao
 

WillieNelson

Well-Known Member
WOW! The amazing part is that fire didn't start on that closely packed, unventilated ballast "rack". I guess that guy learned what not to do...
 

tmpsanity

Well-Known Member
You know, I hope this thread can grow into a follies, foibles and fuck-ups for refrence. However, I also hope never to be one whom is added under heading of "what not" to be. Nice pics AL.
 

WillieNelson

Well-Known Member
It would be nice to write an "everything" guide to electric. But I have been working in the feild for 2 decades and it changes everyday. I found humor in the drawing in the gallery here of a guy using a 220v plug to run 2-110v lights. Not that it wouldn't have worked, but just a little unstable to series connect my lights.
 

Al B. Fuct

once had a dog named
It would be nice to write an "everything" guide to electric. But I have been working in the feild for 2 decades and it changes everyday.
Not THAT much. ;)

I found humor in the drawing in the gallery here of a guy using a 220v plug to run 2-110v lights. Not that it wouldn't have worked, but just a little unstable to series connect my lights.
Well, that guy was me! :lol:

If you had seen the thread that image accompanied, you would note that I gave some serious caveats about the types of loads that admittedly shonky ckt should run (plain resistive). I also suggested that it wouldn't work well on loads like HPS lights as the current draw of each light, even if identical, may not come up and drop at the same times as the tubes heated and then struck an arc. Not the best engineering judgment on my part, but hey, it was a quick fix that would work in some cases... but I also ultimately disadvised using the ckt as I drew it.

I've done some somewhat more sensible simple things in that department, though. ;)
 

Spittn4cash

Well-Known Member
I work on live DC circuits all the time ;-)

...Of course they're only between 5-12Vdc...but they're live, does that count?

Im trying to set my whole garden up in DC, with a bunch of power inverters and maybe some car batteries.. any suggestions?
 
Top