Hi
I will have to be installing a 8ft ground rod to meter box an wanted to know some of the basics on it .-
Is it required to be in condoit?
And can the bare copper be in same conduit as main feed wires going from meter box to panel?
An am i to have 2 rods?
Is it best to be as close to meter as possible an have the bare copper wire enter lower side of meter box or is it to go into bottom?
Also can it be joined to same lug [neutral feed after meter has a side lug bolted to box off neutral.], inside meter box, as the bare copper wire from panel ground will be ?
Can water pipe be used as 2nd ground source ,an would i go from rod to pipe?
Any other important things i need to know please do share.
Thanks
Let me take your questions in the order you asked them:
You are allowed to use #6 American Wire Gauge (6AWG) as the Grounding Electrode Conductor (GEC) when connecting to Driven Rod Electrodes. If you use 6AWG and it is exposed to physical damage; such as adjacent to a walkway, or similar exposure you must protect it from damage by Enclosing it in Rigid Metal Conduit or Schedule 80 Rigid Non Metallic Conduit. It must be protected all the way to the connection to the rod or to a depth of 2 feet. The way to avoid that is to use #4 AWG Copper (CU) as the GEC because #4 and larger conductors are only required to be protected when exposed to severe physical damage. One examples of such exposure include grass that goes right up to the GEC making exposure to powered lawn equipment nearly inevitable. Another would be installation immediately adjacent to a driveway. In such cases even conductors as large as #4 AWG would require protection. Removing the sod and replacing it with a one foot or wider strip of mulch were the GEC enters the earth will satisfy most Authorities Having Jurisdiction (AHJ); read electrical inspectors; that the GEC is not exposed to powered landscaping equipment.
There is no reason to have an additional conductor in the raceway containing the Service Entry Conductors. The connection provided in the Meter Enclosure; meter can; is enough to connect the portion of the Grounding Electrode System to the Grounded Current Carrying Conductor; neutral.
As to the number of Driven Rod Electrodes (ground rods) you must have it can be a single rod if it has an impedance to ground of 25 Ohms or less. If the impedance of the single rod is more than 25 Ohms you will need to drive a second rod at least 6 feet away from the first rod. Since the equipment to test that impedance is quite expensive most installers simply install the second rod. The National Electrical Code allows the first rod to be driven right next to the wall on which the meter is mounted but that is well short of best practice.
The GEC should enter the meter can through a knock out in the bottom of the enclosure. Look carefully and you will find a knock out almost immediately below the GEC lug in the bottom of meter can in the case of most manufacturers' enclosures.
Best practice is to drive the ground rods into an area of soil, that has a radius around the rod which is the length of the rod itself and which is free of any underground structures including the basement wall or foundation of the home. That would mean that you would drive an 8 foot rod at least 8 feet out from the basement wall or foundation. Best practice is to drive the second rod at least twice the length of the longest rod away from the first. For two 8 foot rods that would be sixteen feet apart.
A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing bonded to the pipe) must be connected to the Main Bonding Jumper using a terminal that is attached to the Neutral Buss in the Service Equipment Enclosure. So not only may you use it, you are required to use it as part of the Grounding Electrode System (GES) if it is available. It must be connected using a #4 AWG or larger CU conductor. The connection to the underground metal water pipe has to be made within 5 feet of were that piping enters the home. Pest practice is to make that connection on the supply side of the first shut off valve. That is because no one is likely to disturb piping that they cannot shut off. As long as that GEC is run inside the house it is unlikely to require physical protection. If for some good reason you were connecting from the driven rods to the underground metal water piping the GEC connecting the rods to the meter can's lug would have to be sized to the code requirement for the GEC to the water piping rather than the size required for the driven rods. That is so that it would be large enough to serve as the connection to the water piping via the driven rods. If instead you connected from the Service Equipment Enclosure's neutral buss to the water piping and then from the water piping to the driven rod electrodes the GEC from the pipe to the driven rods would only need to be sized to that required for driven rods which is #6 AWG.
If the water piping supplying water to the home is non metallic or less than 10 feet in length then you only need to bond the neutral to any metal water piping inside the home. That connection can be made at any convenient point on the interior metallic piping system.
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Tom Horne