Had an "temporary" inspector gig me many years ago for using one continuous piece of #6 bare CU GEC to hit both ground rods. He said that I had to use a #4 minimum for this type of installation. I quoted what is now 250.53(E) and his response was (1) the article makes no mention of multiple driven rods and (2) good ol' 90-4. Being a young, hot-headed apprentice, I argued with him......loudly.....before we eventually complied. Saw him again years later as I was taking my Supervising Journeyman test. Turns out he was the State Assistant Chief Electrical Inspector who writes, proctors and grades the test. First test I ever failed. Today I have my own shop and don't even stock #6 bare.
Driven ground rod
- Thread starter magoo66
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stud696981
Senior Member
Re: Driven ground rod
For ground rods you do not need to use larger then #6......unless there is a local code that says different.
For ground rods you do not need to use larger then #6......unless there is a local code that says different.
stud696981
Senior Member
Re: Driven ground rod
Unless there is some local code that says different, you only need to use one wire to feed multipule ground rods.
The inspector probably needs to be retrained!
Unless there is some local code that says different, you only need to use one wire to feed multipule ground rods.
The inspector probably needs to be retrained!
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: Driven ground rod
What part of "...that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper..." doesn't apply to multiple ground rods? What a goob!
A GEC to two rods that is unbroken has a sole connection to each ground rod. At that point, it isn't required to be larger than #6.
From what I hear, a ground rod wouldn't be able to make use of any more conductor anyway, so there's no point to upsizing it.
What part of "...that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper..." doesn't apply to multiple ground rods? What a goob!
A GEC to two rods that is unbroken has a sole connection to each ground rod. At that point, it isn't required to be larger than #6.
From what I hear, a ground rod wouldn't be able to make use of any more conductor anyway, so there's no point to upsizing it.
Re: Driven ground rod
This was a 320a meter main (2-200a mb) mounted on two 4x6 pt posts in a residential yard. I sleeved the GEC in sch. 40 pvc to below grade. I know sch. 40 isn't necessarily "physical protection" but that wasn't his beef anyway. He said that because of the increased surface area of two rods -and- because this is a 400a(320) service that I needed the heavier wire. I don't think that is the intent of the code.
This was a 320a meter main (2-200a mb) mounted on two 4x6 pt posts in a residential yard. I sleeved the GEC in sch. 40 pvc to below grade. I know sch. 40 isn't necessarily "physical protection" but that wasn't his beef anyway. He said that because of the increased surface area of two rods -and- because this is a 400a(320) service that I needed the heavier wire. I don't think that is the intent of the code.
charlie
Senior Member
- Location
- Indianapolis
Re: Driven ground rod
If you had a 10,000 ampere service, you could still use a ground rod with #6 Cu. for the GEC to the ground rod. If you needed a second rod, you could install a #6 Cu. bonding jumper to that one from the first one.
George, you prose is interesting but correct (even your description of the AHJ).
If you had a 10,000 ampere service, you could still use a ground rod with #6 Cu. for the GEC to the ground rod. If you needed a second rod, you could install a #6 Cu. bonding jumper to that one from the first one.
George, you prose is interesting but correct (even your description of the AHJ).
allenwayne
Senior Member
Re: Driven ground rod
Maybe he was using 250.66 in making hid decision :roll:
Maybe he was using 250.66 in making hid decision :roll:
Re: Driven ground rod
The #6 wire rule and the 25 ohm rule are 150 year old rules from when telegraph systems were wired with #6 steel wire.
There is no Code rule that covers 2 rods or plates on the same GEC as far as size goes.
250.64(B) can be interpreted as requiring #4 copper wire for a ground rod. A lot of places require a minimum of #4 solid copper or #2 stranded copper - so many GECs run crosswise to joists that they do not want to check every foot of the GEC.
The #6 wire rule and the 25 ohm rule are 150 year old rules from when telegraph systems were wired with #6 steel wire.
There is no Code rule that covers 2 rods or plates on the same GEC as far as size goes.
250.64(B) can be interpreted as requiring #4 copper wire for a ground rod. A lot of places require a minimum of #4 solid copper or #2 stranded copper - so many GECs run crosswise to joists that they do not want to check every foot of the GEC.
- Location
- Massachusetts
Re: Driven ground rod
Securing and Protection from Physical Damage
Size of Alternating-Current Grounding Electrode Conductor.
How can we know what they mean?
But Roger it is to confusing for us simple electricians.
Securing and Protection from Physical Damage
Size of Alternating-Current Grounding Electrode Conductor.
How can we know what they mean?
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Driven ground rod
Then if we don't agree we can switch over to our psycho powers.
[ July 20, 2005, 02:14 AM: Message edited by: hurk27 ]
We could start practicing our psychic powers and read the AHJ's mind to know what they want.
Then if we don't agree we can switch over to our psycho powers.
[ July 20, 2005, 02:14 AM: Message edited by: hurk27 ]
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