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| Subject - GROUNDING RODS | |
| AMPMWIRED |
I INSTALLED A 200 AMP MAIN PANEL WITH A 8 FOOT STANDARD COPPER GROUNDING ROD WITH THE PROPER GROUND CLAMPS. THE CITY INSPECTOR FAILED THE GROUND ROD,SAYING THE SOIL IS VERY COROSIVE & CAN DESTOY THE GROUND ROD,(YA IN 100 YEARS).THE CITY IS MAKING ME INSTALL A STAINLESS STEEL GROUND ROD.ARE THERE ANY CODES BASED ON GROUNDING RODS & TYPES OF SOILS, OR IS THIS JUST A CITY INSPECTOR WITH A ROD UP HIS ... THANKS
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| Scott Vickrey | The 2002 NEC code section 250.62 Grounding Electrode Conductor Material specifies copper, aluminum or copper-clad aluminum. And, the material selected should be resistant to the corrosive conditions where you install it. The section also requires the electrode to be protected against corrosion. Remember the code is the minimum required protection, and the local or authority having jurisdiction has the final say on what is required. I have never seen a stainless steel ground rod. I wonder what that puppy's going to cost and what type of clamp they expect you to use? |
| JimmyDee | Our area is requiring 2 ground rods that are at least 6ft apart, (artical 250.58) so I would check that out also. The code says that it is required if you can not prove 25 or less ohms to ground.  It cost a lot to have the system tested so everyone is installing 2 ground rods.Hate to think of what 2 SS ones is going to hit you. What kind of wire are they saying you need? Jim |
| David Hyatt | Speaking of ground rods, I was told it is almost impossible to get 25 ohms to ground with a 8' ground rod. But by installing 2, the code would keep you from being liable even if there is not 25 ohms to gnd. Is this true? |
| JimmyDee | quote: Yes it is as long as they are a min of 6' apart. They recommend further apart but 6' is the minimum. Jim |
| AMPMWIRED | THANKS FOR THE FEED BACK. THE AREA WERE THE ROD WAS INSTALLED IS VERY CLEAN AND FREE OF ANY CORROSIVE MATERIALS.IT IS A MACHINE SHOP THAT MAKES AIRCRAFT PARTS,YOU COULD EAT OFF OF THE FLOOR.THE INSPECTOR IS REGARDING ABOUT THE SOIL UNDER THE BUILDING BEING CORROSIVE BECAUSE THEY HAD OIL DRILLS SET UP FOR MANY YEARS.REGARDING THE GROUNDING RESISTANCE, A# 4 THHN COPPER WIRE WAS PULLED FROM THE MAIN SWITCH GEAR TO THE 75 KVA TRANSFORMER.GROUNDING BUSHINGS WERE USED ON BOTH ENDS.A 3/0 THHN COPPER WIRE WAS USED FROM TRANSFORMER TO THE GROUND ROD.THE #4 WIRE AND 3/0 WIRE WERE BONDED UNDER XO AT THE TRANSFORMER. IT JUST HAPPENS THAT THE MACHINE SHOP CAN GET A S.S. ROD FOR ABOUT $75. |
| gregm | this sounds like a separately derived system, not a service since you pulled from "the main gear" and were bonding to "X0" so you should be bonding to the grounding electrode system that exists for the building, or to effectively grounded building steel in the building. if it is an industrial location (sounds like it is) and there are qualified people maintaining the installation, you could bond to interior metal water piping if it is exposed its entire length back to where it enters the building. if you drove new rods for this system and there is also a service for the building you need to bond the two electrode systems together. good luck |