Yes, it is. Without his permission I won't reveal his (Yup, a Dude) name, but I do appreciate his generosity and will tell you that he is affilliated with Harbor Freight.
Go buy stuff from Harbor Freight!!! How's that for a shameless plug?
Also, Jason, thanks for sending me this link on grounding written by someone that tells it better than I can:
http://www.peavey.com/support/technotes/safety/shockhazard.
I encourage EVERYONE to read this that has an A/C powered system. Good info here. Like you said, especially the last two paragraphs.
Here is a little more info on grounding:
http://www.epanorama.net/documents/groundloop/why_grounding.html************************************************
Grounding in wiring
Today's modern (US.) mains cable consists of three separate wires: black, white, and green. The green wire is always connected to the large ground pin on the plug, and the other (green) end connected to the chassis of the equipment. The black wire is always considered to be the "hot wire," and as such, is always the leg which is connected to the switch and fuse. The white wire is always the neutral or common wire.
European coloring is a little bit different. The ground wire is here green wire with yellow stripe. Neutral wire is blue. Live wire in Brown (additional colors for the live wires used in 3 phase systems are black and black with white stripe).
Any modification of the above 3 wire mains system completely eliminates the protection given by the three wire configuration. The integrity of the separate ground path is also directly related to the quality of the receptacle and the wiring system in the building itself.
The neutral (grounded conductor) must be solidly connected (bonded) to the home's ground system at the first disconnect (main panel). This keeps large voltage differences from developing between the neutral and ground.
Currents in grounding wire
Ground wires should not carry current except during faults. If the ground wire carries any current there will be a potential difference between different grounding points (bacause the current flowing in wire causes voltage drop because wire resistance). This is why a common wire which works as neutral and grounding wire is very bad thing.
When there is separate wiring for grounding you can't still completely avoid the current flowing in grounding wires ! There will always be some capacitive leakage current form the live wire to the ground wire. This capacitive leakage current is caused by the fact that the wiring, transformers and interference filters all have some capacitance between the ground and live wire. The amount of current is limited to be quite low (limited to be between 0.6 mA to 10 mA depending on equipment type) so it does not cause dangers and big problems. Because of this leakege current there is always some current flowing in the ground wire and the ground potentials of different electrical power outlets are never equal.
The leakege current can also cause other type of problems. In some situations there are ground fault detect interrupter (GFCI) circuits in use the leakage current caused by many equipments together can make the GFCI to cut the current. Typically GFCI circuits are designed to cut current when there is 30 mA or more difference in currents flowing in live and neutral wires (the difference of those current must flow to ground). Some GFCI circuit can cut the mains feed even at 15 mA leakage current which may mean that if you connect many computer equipments (each of them having 0.5 to 2 mA of leakage) to GFCI protected power outlet you can cause the GFCI to cut the power feed.
Ground wire resistance
In europe it is not important how much ohms the grounding is but the maximum current before the unit switches off is important. So a grounding of 230 volts and a safety of 24 volts. We say it must be less then 30 mA in our body. So for 16 amps and 24 volts it is 1.5 ohms. This means that the maximum voltage on the case is 24 volts even when all current is flowing thru the grounding wire. In places where even this 24V is considered very dangerous (for example in hospitals) the ground resistance must be made lower to make sure that there is never dangrous voltage present in the case. For example in Finland the grounding resistance for medical room outles must be less than 0.2 ohms to be considered safe.
The above is the objective, and all the crap around it is just to make it difficult. Ground means something connected to the surrounding and it must be less then x ohms measured with AC and the wire must handle the short circuit current present in the circuit without overheating.
Sources
Frequently Asked Questions on Electrical Wiring by Chris Lewis and Steven Bellovin
Grounding article from CodeCheck.com
Shock Hazard and Grounding by Jack Sondermeyer from Peavey (web document which is no longer available)
Other useful grounding links
Why Ground ? - from Q & A Electrical from CodeCheck.com
The shocking story of grounding
Two Modern Power Quality Issues - Harmonics & Grounding from Copper Building Wire home page
Residential Wiring and Grounding Guidelines from Power Clinic
The Hows and Whys of Isolated Grounding
United States Practices to Protect People and Equipment Against Lightning from Power Quality magazine
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Dave, out for a while........ I'm taking time off from the forum. My brain hurts.
