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Home > Archive > Electrical Engineering > August 2005 > Code Question
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| I jjust failed a service upgrade inspection and I need some opinions.
The service went from 100 amps to 200. The existing grounded electrode
conductor goes directly to a driven ground rod using number 6 copper
and aanother ground wire using 4 aluminum goes to the water pipe. the
water pipe goes to a meter and is connected to PVC pipe that goes into
the concrete basement floor. The AHJ wants the wire going to the water
pipe to be sized according to 250-66 because he states that the water
pipe is a grounding electrode and the rod is a supplemental ground. He
also wants a jumper around the water meter. My contention is that
according to 250-52 the water pipe is not an electrode unless it is in
contact with the earth for 10 feet. I considered the ground rod the
grounding electrode and used and the water pipe as stated in 250-104.
Not that it matters since it is an easy fix and he is the AHJ, but I
would like to know where if at all I went wrong.
Thanks for any and all replies.
Tom
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| daestrom 2005-08-13, 12:21 pm |
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"Tom" <notreal1234@comcast.net> wrote in message
news:dlrrf19s9pur8mank91gr05b8v2nj28r0k@4ax.com...
> I jjust failed a service upgrade inspection and I need some opinions.
> The service went from 100 amps to 200. The existing grounded electrode
> conductor goes directly to a driven ground rod using number 6 copper
> and aanother ground wire using 4 aluminum goes to the water pipe. the
> water pipe goes to a meter and is connected to PVC pipe that goes into
> the concrete basement floor. The AHJ wants the wire going to the water
> pipe to be sized according to 250-66 because he states that the water
> pipe is a grounding electrode and the rod is a supplemental ground. He
> also wants a jumper around the water meter. My contention is that
> according to 250-52 the water pipe is not an electrode unless it is in
> contact with the earth for 10 feet. I considered the ground rod the
> grounding electrode and used and the water pipe as stated in 250-104.
> Not that it matters since it is an easy fix and he is the AHJ, but I
> would like to know where if at all I went wrong.
> Thanks for any and all replies.
> Tom
Well, I'm not the most expert on NEC (there are some here that should be
able to help you). But I more or less agree with you. First, the water
meter should *always* be jumpered. You never know when a replacement will
be installed, or what sort of changes a plumber may put in (and it's a
pretty easy thing to do). Second, if you have PVC water main to your house,
I can't see how it can be considered a ground of any kind. So don't you
need a second grounding rod?
If you have copper pipes in the house, and PVC supply, then the connection
from the copper pipe to the service panel ground is really more of a
'bonding jumper' isn't it? Just 'bonding' all the metal piping in the house
to earth?
daestrom
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| SQLit 2005-08-13, 12:21 pm |
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"Tom" <notreal1234@comcast.net> wrote in message
news:dlrrf19s9pur8mank91gr05b8v2nj28r0k@4ax.com...
> I jjust failed a service upgrade inspection and I need some opinions.
> The service went from 100 amps to 200. The existing grounded electrode
> conductor goes directly to a driven ground rod using number 6 copper
> and aanother ground wire using 4 aluminum goes to the water pipe. the
> water pipe goes to a meter and is connected to PVC pipe that goes into
> the concrete basement floor. The AHJ wants the wire going to the water
> pipe to be sized according to 250-66 because he states that the water
> pipe is a grounding electrode and the rod is a supplemental ground. He
> also wants a jumper around the water meter. My contention is that
> according to 250-52 the water pipe is not an electrode unless it is in
> contact with the earth for 10 feet. I considered the ground rod the
> grounding electrode and used and the water pipe as stated in 250-104.
> Not that it matters since it is an easy fix and he is the AHJ, but I
> would like to know where if at all I went wrong.
> Thanks for any and all replies.
> Tom
Where I live water pipes are bonded cause there is almost no metallic
systems left in the ground. That even includes the gas piping. Most new
homes are all plastic piping for water and say so on the service. They do
not even bother to bond the metallic entry piping anymore.
Changing a service where I live you would need 2 ground rods connected
properly.
From what you said there is plastic between the house and the underground
piping. Sort a defeats the meter jumpers does it not. If I understand what
your saying correctly.
Appears to me that you had an inspection that did not see all of the
situation.
I agree with you up to a point. I would have called ya on the second ground
rod. Which is a biggie here now. Unless of course you provide testing of
the rod and it is under 25 ohms.
I try to maintain everything I do at under 5 ohms.
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| gfretwell@aol.com 2005-08-13, 3:21 pm |
| On Sat, 13 Aug 2005 09:01:06 -0400, Tom <notreal1234@comcast.net>
wrote:
> I jjust failed a service upgrade inspection and I need some opinions.
>The service went from 100 amps to 200. The existing grounded electrode
>conductor goes directly to a driven ground rod using number 6 copper
>and aanother ground wire using 4 aluminum goes to the water pipe. the
>water pipe goes to a meter and is connected to PVC pipe that goes into
>the concrete basement floor. The AHJ wants the wire going to the water
>pipe to be sized according to 250-66 because he states that the water
>pipe is a grounding electrode and the rod is a supplemental ground. He
>also wants a jumper around the water meter. My contention is that
>according to 250-52 the water pipe is not an electrode unless it is in
>contact with the earth for 10 feet. I considered the ground rod the
>grounding electrode and used and the water pipe as stated in 250-104.
>Not that it matters since it is an easy fix and he is the AHJ, but I
>would like to know where if at all I went wrong.
>Thanks for any and all replies.
>Tom
As you can tell there are other meanings for "AHJ", especially the
"AH" part. IMHO you are right but I am not the AHJ there.
Does your state require licensing for inspectors?
You should jumper the meter with nylon rope to bond the plastic pipe.
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| daestrom 2005-08-13, 7:21 pm |
|
<gfretwell@aol.com> wrote in message
news:14dsf15kgosjj6u66ubnuu2cn79o7f6s5g@4ax.com...
<snip>
>
> You should jumper the meter with nylon rope to bond the plastic pipe.
ROFLMAO!!!!
daestrom
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| BFoelsch 2005-08-13, 8:21 pm |
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<gfretwell@aol.com> wrote in message
news:14dsf15kgosjj6u66ubnuu2cn79o7f6s5g@4ax.com...
> On Sat, 13 Aug 2005 09:01:06 -0400, Tom <notreal1234@comcast.net>
> wrote:
>
>
>
> As you can tell there are other meanings for "AHJ", especially the
> "AH" part. IMHO you are right but I am not the AHJ there.
> Does your state require licensing for inspectors?
>
> You should jumper the meter with nylon rope to bond the plastic pipe.
I remember hearing kids talk about jump rope, but now I know what it REALLY
means!
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| On Sat, 13 Aug 2005 14:01:02 -0400, gfretwell@aol.com wrote:
>On Sat, 13 Aug 2005 09:01:06 -0400, Tom <notreal1234@comcast.net>
>wrote:
>
>
>
>As you can tell there are other meanings for "AHJ", especially the
>"AH" part. IMHO you are right but I am not the AHJ there.
>Does your state require licensing for inspectors?
Yes they do New jersey. He was very nice about it but could not
really answer my qustions about why he required what he did.
>
>You should jumper the meter with nylon rope to bond the plastic pipe.
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| Paul S. 2005-08-14, 12:21 pm |
|
<gfretwell@aol.com> wrote in message
news:14dsf15kgosjj6u66ubnuu2cn79o7f6s5g@4ax.com...
> On Sat, 13 Aug 2005 09:01:06 -0400, Tom <notreal1234@comcast.net>
> wrote:
>
>
>
> As you can tell there are other meanings for "AHJ", especially the
> "AH" part. IMHO you are right but I am not the AHJ there.
> Does your state require licensing for inspectors?
>
> You should jumper the meter with nylon rope to bond the plastic pipe.
That's funny, but you still must bond the plumbing system with conductor
sized according to
250-66. In most areas that can be done anywhere in the cold water plumbing
system. Here
they require everything the OP was - in case the polyethylene water service
is ever replaced
by copper.
I remember a job where the customer was getting zapped everytime he
touched
his kitchen sink or got out of his bath tub. Turned out someone had used
SEU to feed a JennAir; the braided EGC
was connected to the ground bus in the panel which hade been converted into
a subpanel
from a main. Whoever did the change over removed the main bonding jumper
screw from
the former main panel. However, they never ran a separate EGC to the new
main. With the 120volt JennAir exhaust blower on (which didn't work for
obvious reasons) there would be 120v on every metallic part in the plumbing
system. This could've easily killed someone. The AHJ requirement in the
OP's case would've prevented the shock hazard
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| Tom wrote:
> I jjust failed a service upgrade inspection and I need some opinions.
> The service went from 100 amps to 200. The existing grounded electrode
> conductor goes directly to a driven ground rod using number 6 copper
> and aanother ground wire using 4 aluminum goes to the water pipe. the
> water pipe goes to a meter and is connected to PVC pipe that goes into
> the concrete basement floor. The AHJ wants the wire going to the water
> pipe to be sized according to 250-66 because he states that the water
> pipe is a grounding electrode and the rod is a supplemental ground. He
> also wants a jumper around the water meter. My contention is that
> according to 250-52 the water pipe is not an electrode unless it is in
> contact with the earth for 10 feet. I considered the ground rod the
> grounding electrode and used and the water pipe as stated in 250-104.
> Not that it matters since it is an easy fix and he is the AHJ, but I
> would like to know where if at all I went wrong.
> Thanks for any and all replies.
> Tom
Here's my guess:
The inspector is looking for 2 electrodes, and finds them,
by *your* interpretation, because there is only 1 ground
rod. The logic is: had you decided that the water pipe
was not an electrode, you would have driven another rod,
or proved 25 ohms or less from the existing rod (250.56)
Ed
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| petersonra@aol.com 2005-08-16, 6:21 pm |
| just out of curiousity.
why would you care if your ground resistance exceeds 5 ohms and why
would you bother to test it to find out in the first place?
just pound two rods and be done with it.
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| Hei,
I thought you need to spent 20K to get less then 1 ohm resistance.
tks
magic
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<gfretwell@aol.com> wrote in message
news:14dsf15kgosjj6u66ubnuu2cn79o7f6s5g@4ax.com...
> On Sat, 13 Aug 2005 09:01:06 -0400, Tom <notreal1234@comcast.net>
> wrote:
> You should jumper the meter with nylon rope to bond the plastic pipe.
LMAO
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