If an electricity sub-station flooded before being "switched off" what would be the size of the danger area?

Question

If you were in the water, how far away would you have to be to avoid being electrocuted?

Answer 1

The killer is current passing through the body, causing muscles, like the heart, to freeze (stop). And, of course, sufficient current and the heat it can create will also burn tissue, which could ruin your day as well.

Wattage is found from P = EI or I^2 R. E (voltage) is = IR. So the danger to your drenched bod, as the substation shorts out, is found by p/R = I^2; where p = P - L is the power of the substation short (P) minus the power lost (L) as the current travels to where you stand, and R is your body resistance.

Now electricity is lazy, it will take the path of least resistance. So as the current from the shorted substation courses through the water, which is contaminated with whatever it can pick up from the soil, it is looking for the easy way out.

If your body's resistance is greater than, say, the surrounding water's resistance, most if not all the current from that substation will continue to make tracks through the water; not your body. In which case, you may be OK even close in to the source...the substation.

If your body's resistance is lower than the surrounding pool of water, I am afraid you are in for a shock (pun intended). The current will channel through you when it finds that lower resistance in your body. Just how much current, as we saw earlier, depends on the power level at the point of entry into your body. And that in turn depends on the power of the substation's short out minus the power lost as the current fans out from the source through the water.

The math to figure out how far you might stand and still survive has so many variables in it, that unless a particular case is specified, we cannot say how far you can be from the substation and still survive. But death is possible at current ranging from 50 to 150 mA (milli amperes). [See source.] And death is increasingly more likely when the current is increased, goes through vital parts of your body, and/or lasts for longer periods through your body.

One answer mentioned the automatic shutdown capabilities of substations. They do have them, but sometimes they do not work. The Great Northeast Blackout of 1965 was caused by a substation in Ohio or western Pennsylvania, I don't recall which one, that shorted out and did not automatically shut down. Instead, the surge of current from the short coursed through the entire power grid of most of northeastern U.S. amd southeastern Canada to put that entire region into the dark without power.

Answer 2

That would depend on the size of the sub station. How much power is it putting out (Watts)? Sub stations have fail safe features installed that would automatically shut off the power if it were being flooded so I doubt this would ever happen.

Answer 3

It depends on how much energy is in the plant. It also depends on how much water is there. My guess would be to stay out the water at ALL costs.