Ground? Where?

[Steven Dufresne]

Here's the example for a car - Top Gear video of 800,000V arcing to car and then to ground while the driver is sitting in it unharmed.
-Steve
http://rimstar.org   http://wsminfo.org

[gravityblock]

There is a BIG difference between "Ground" and "Shield".  The Frame of a vehicle of any kind is a shield, not necessarily a ground.  (This is why ALL aircraft have static ports on them, but that's another story.)

There is no difference in the purpose of the earth ground or a shield.  Just because the frame isn't put into the dirt, doesn't mean it's not serving the same purpose as a 8ft. thick copper rod that is in the dirt.  They both divert as much excess external energy away as possible to prevent damage and fire to internal components. Their is no guarantee it will be successful in any system since the possibility is always there for it to jump into the internal wiring of the house or vehicles causing damage and fires.

The static ports on the airplanes is for static build up.  The aluminum skin is for lightning strikes.  Then you can have fuses and surge protectors for the inside wiring for additional protection.   Lighting rods with the large ground cables running on the outside of the house is additional protection against direct hits on the house instead of the outside service wires being hit.  Utility ground offers protection against transformers blowing, etc. The purpose of all of this is for protection and the dirt doesn't make it any more "grounded" than other methods.  Grounding means a certain level of protection, it doesn't mean the excess external energy has to be bled off into the physical ground of the dirt in order for it to be grounded or protected.

I installed satellite dishes for a number of years and I know what the purpose of grounding is and we had many options.  Grounding to cold water pipes, metal frames of mobile homes, the copper ground rod, the meter box, etc.  They all served the same purpose, to bleed off the static build up on the dish! 

Same thing with shielding the magnetic flux of a magnet.  The shield only diverts the return path of the field by allowing the flux to flow in the shielding material instead of passing through it.  If the material isn't thick enough for the strength of the field, then the field will pass through the material.  In fact, if you're trying to shield a south pole with a material, then the material must have a north pole attached to the material before the path is diverted.  My videos on how to shield the magnetic field successfully and it's the reason for so many failures because most of the time it's not done properly, http://www.youtube.com/watch?v=_81SxByRNR8 and http://www.youtube.com/watch?v=aJFgMB5ezsE


GB

[gravityblock]

I agree with you Loner.  People with different backgrounds have a different perspective on things.


Thanks for the info,

GB

[IotaYodi]

You also have the "Standard" BX cable, which is the flexible power wiring with a metal encasement, which CAN be used as ground, but again not to flow a neutral.   (That is done more than you want to know...)  The Actual purpose of both of these is shielding the AC component from radiating out of the conduit, and not for grounding, but to the electricians, this IS the 3rd wire "Ground".

I have never run conduit or any type bx cable without an insulated ground. This is code.
I have lost a in ground water pump,2 tvs,and a stereo all at one time. My computers had surge protection so I didnt lose them. I didnt lose my 10 ft. sat dish either. I had surge protection put on for my tvs afterward. I have an Audio studio also but thats all on surge protection with a separate service so no damage there. I also have a 32 foot galvanized weather mast with no problems.
I had surge protection put in on my service meter to protect the major appliances. I wish Florida would make that mandatory. Next to Africa we get the most lightning strikes.
Here is an excellent view of lightning exiting the static wick on a plane.
http://www.youtube.com/watch?v=8o2oachaHXY

[jadaro2600]

If a space station has a conductive skin completely around it, then it will act as a Faraday Cage even in space.  Do you still think it's not wise to use this conductive skin or metal frame for protection?  Apparently the high voltage line workers think it is wise and I don't think additional wires would protect those workers or the helicopters.

Equalizing potential differences and grounding are two different things.  The Helicopter you mention does this for safety...

I once knew someone that tested the lines like this, he mentioned a colleague that was injured because the path didn't go to the probe but decided to ground out to one of his dental fillings instead.  This doesn't stop the discharge from being unpredictable.  It seems to do what it wants.

If the car were grounded, I think the battery would leak.