Really large induced ground fault currents

The generic term for these faults is "stray current", and although the article seems to consider just a few tens of amps of stray current as a big deal, in the industry where I work in we don't really notice these "stray currents" until they reach hundreds or thousands of amps. It's kinda sad, but the threshold seems to be front-page-of-the- Washington-Post!

Tim.

Sounds like a good source of "free" power to me.

Could this really be true?

Any physics types out there that can calulate how strong the magnetic field would have to be to create that kind of induced power __in free air__.

I would think that any ferrious metal objects and audio systems in the area would be humming a tune and CRT displays would be dancing to it.

Mark

When you have stray current flowing through ground that also happens to contain natural gas pipelines and storage tanks, and they notice it because all of their metal is corroding far faster than it used to, it doesn't seem so "free" no more!

Tim.

To give you an idea of the environment I work in, color CRT displays every few minutes twist and turn funny colors. And I'm five to ten feet from the rather small (few square feet) current loop. Of course when the current is 10,000Amps... :-).

The gotcha in the article was that there were two loops both of very large area in the original wire layout. If either loop had small area then there wouldn't have been such a problem. Every so often I run across a consumer product where there's large loops and make them especially susceptible to 60Hz (or n*60Hz in my office from the multiphase rectifiers) hum but for the most part the professionally produced stuff knows to eliminate the loops.

Tim.

out:

I dunno, I think the power worked out to about 700 watts. Thats a lot of uncontrolled power to be dissipating from one point off your house siding.