You trace the grounding electrode conductor - bare copper wire - from the main panel to a ground spot outside.
How do you know what (if anything) it‚Äôs connected to? See exhibits in NEC 250.50; the connection point could be 30 inches deep.
How can you confirm the buried electrode‚Äôs length?
Is there a way to test if the grounding system works electrically?
While working as a Building Inspector at a seaside community, I once inspected a grounding installation that I will always remember.
The house was surounded by beach sand and I followed the copper wire to a point where it went under the sand. As I pulled on the wire to see where it lead, up came the rod, all two feet of it! The second ground was the same. Needless to say he failed.
When asked why he would do such a thing especially with the sand so soft?
The answer came down to Greed! You get alot more ground rods when you cut a 8' rod in 2' pieces.
No other inspector had ever tried this before.
GS99, why do you have concerns about your grounding.
I obtained a house that has some "deceptive" 3-prong outlet faces, but they're not grounded - old style cables with no ground wire. The pre-purchase inspector pointed this out to us, but I don't remember that he checked for an effective grounding system. (Any deceptions buried in the non-sandy ground?) The house does have an additional grounding conductor to the cold water pipe, (within 5 feet of entrance, all pipes are exposed).
So the questions:
(1) What happens if this system is severed completely from the house main panel? (ie. personal safety, equipment failure etc.)
What part does the Utility transformer ground play?
(2) Is there a "simple" test (like a GFCI test) that a homeowner could do that assures the electrical effectiveness of a grounding conductor to an electrode?
(3) If the answer to #1 is "serious", should there be an automatic panel shutdown?
I'll be the first to admit, I'm not the most knowedgable in this subject.
I moved on from inspecting to Zoning and Code enforcement. I now have a whole team of inspectors that specialize in thier fields to fall back on.
If I were you I would do like Rick stated and hire an electrician to perform an inspection to ensure that the past work is safe.
It sounds to me that new outlet recepticles were installed in a two wire system. I would spend the money to have the proper circuts protected.
A GFI tester can be purchased at any hardware store for about six bucks.
I would make sure that all bathroom and any recepticles within 6' of a sink be GFI protected, unless it is a dedicated circut, like the plug behind a refer.
[This message has been edited by joed (edited November 30, 2002).]
‚ÄúAn illegal, loose or corroded clamp will provide a poor connection to the rod‚Ä¶‚Äù
Above quotes from ‚ÄúWIRING A HOUSE‚Äù (The Taunton Press) by Rex Cauldwell. The author indicates the benefits of multiple electrodes and viewing metal water pipes in a different way - needing to be grounded instead of serving as a grounding conductor/electrode.
Thanks for all the replies to my post.
There are valid reasons to be concerned: deceptive workmanship sometimes caught by inspectors, material degradation caused by various natural processes, new equipment in the house, etc..
Is the grounding system as important as overcurrent protection? Shouldn‚Äôt there be an integral part of the electrical system that monitors its grounding system, similar to the way overcurrent protection and GFCI devices work continually? When electrical wiring was first being installed years ago, electricians were probably called in to check if the wires could carry a certain load. Then someone invented the fuse.
'Grounding' all your receptacles involves running an equipment grounding conductor to each and every receptacle! Lots of work...most folks opt for installing a GFCI to protect personnel (Remember however: a GFCI Does Not give you an Equipment Grounding Conductor and Does Not protect equipment from faults...it does however protect personnel and does give you that 3rd prong).
(1) The words grounding and conductor are found in many expressions. For example the wire that connects the main service panel to a piece of metal stuck in the ground is called ‚Äúgrounding electrode conductor‚Äù. This is different than ‚Äúequipment grounding conductor‚Äù. Why don‚Äôt they provide simpler, single words to these things? Look at all the simple words we‚Äôve learned for computer parts, yet each one brings an immediate picture to your mind. A keyboard and a mouse each have a specific usage ‚Äì no confusion.
(2) Differences among authorities. In the NEC 250.52 ‚ÄúGrounding Electrodes‚Äù, part (A) ‚ÄúElectrodes Permitted for Grounding‚Äù, the first object is (1) ‚ÄúMetal Underground Water Pipes‚Äù. However, others view these pipes differently. (See reference in a prior reply)
I agree, it does no good to have properly installed/connected electrodes if the grounding conductors do not extend throughout the wiring. Most of the wiring in my house is older nonmetallic cable (NM) with only two conductors ‚Äì no grounding wire. Built in early 50‚Äôs, it has no knob and tube wiring.
The ‚ÄúGrounding System‚Äù with all of its parts (including the electrodes) offers protection from various problems in the house, in addition to the effects of lightning. I utilize the expression ‚ÄúGrounding System‚Äù here in the same way ‚ÄúImmune System‚Äù is used for our bodies - it includes objects in various parts of the body each doing their job to protect the body.
Not to be confused with the expression ‚Äúgrounding electrode system‚Äù in the NEC 250.50, referring to multiple electrodes bonded together. At this point, both of my electrodes‚Äô grounding electrode conductors connect within the service panel to the same Neutral/grounding bus; does not resemble the NEC exhibit 250.21, which alludes to a commercial building.
Curious question: If a residential house has multiple (‚Äú8 foot‚Äù) ground rods, with a continous conductor, and no other type of electrode, does that make a ‚Äúgrounding electrode system‚Äù? Or do you need two or more different electrode types?
[This message has been edited by gs99 (edited December 06, 2002).]
BTW, computer terms can get just as complicated and arcane as electrical terms. In C++, for example, an "object" is not necessarily an object in the object-oriented programming sense, which is what many expect an "object" to be.