On 10/23/2015 4:43 PM, westom wrote:
On Friday, October 23, 2015 at 2:22:20 PM UTC-4, Muggles wrote:
Me either! I run for cover when it gets stormy because of the lightning
possibility.

All this stuff is simple once some simply concepts, even introduced in elementary school science, are remembered. An electric current does not flow if it does not have both an incoming and outgoing path. Many things, often considered not electrically conductive, actually are including linoleum tile and earth.

An example. Lightning must connect to earthborne charges maybe five miles distant. A shortest path is three miles down to a tree and four miles through earth. A cow, maybe 40 feet from that tree, is killed. How? Lightning did not strike the cow (according to conclusions based only upon observation). Ah. But lightning did strike that cow. It did have both an incoming and outgoing path. A more conductive cow meant that direct lightning strike went up a cow's hind legs and down its fore legs.

Previously noted was that earthing is an 'art'. This cow is a perfect example. Damage to anything (ie a golfer) is always about how that current flows. Therefore properly constructed barns are surrounded by an earthed loop. A golfer standing with feet together is less likely to be harmed. Concept, in both cases, is called single point earth ground.

In a first example, a lightning current did not find a destructive path via household appliances. In a second case, it did. Protection is always about whether that current needs to connect to charges (maybe four miles away) destructively via household appliances. Or harmlessly outside by some other path. Protection is always about how/where that current flows.

Again, damage is always about the incoming and outgoing path. If that path remains outside, then no current is incoming and outgoing to destroy household appliances.


I understand. Thanks for the explanation.

--
Maggie