Grounding source for 1600 amp service

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geoff mickelson

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I have a question as reguards a grounding source for a1600a 120-208 service. We installed a 10' grounding ring by the utility transformer along with the grond rods in the secondary side of the transformer and brought a bare 4-0 into the MDP. The inspector tells by code we also have to have a 3-0 attached to to the water pipe attached within 5' of the water pipe where it enters the building. We complied. My question is as I read the code tome it says you can use one of serveral methods not that you shall use use a water pipe if you comply with the other alternatives. What say you? Thank-you Geoff Mickelson R&G Electric Humboldt,Ia
 
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If the water pipe qualifies as an electrode, you have to use it also.

250.50 Grounding Electrode System. All grounding electrodes
as described in 250.52(A)(1) through (A)(7) that are
present at each building or structure served shall be bonded
together to form the grounding electrode system. Where
none of these grounding electrodes exist, one or more of
the grounding electrodes specified in 250.52(A)(4) through
(A)(8) shall be installed and used.
 
Grounding source for 1600 amp service

What about harmonics and cuurent on a grouding conductor traveling on the water pipe from one building to another
 
Harmonics should have no effect on the GES. Unintentional current flow on component of the GES sometimes cannot be avoided and are quite common.
 
geoff mickelson said:
What about harmonics and cuurent on a grouding conductor traveling on the water pipe from one building to another
Click to expand...

Why are you placing harmonic current on the water pipe? In a properly installed system this should not be happening. It is your responsibility to see you do not make neutral connections that would allow this. After installation megger all your neutrals t verify you have no ground current. If the water pipe is common between buildings on a common service some current may be present.
 
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brian john said:
In our area less so in commercial properties.
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Yes, not so much in a commercial setting but in residental SF dwellings with a common metal water system there is always some current flowing on the water pipe. At various times, I've measured 1-2 amps in my own house.
 
jumper said:
If the water pipe qualifies as an electrode, you have to use it also.

250.50 Grounding Electrode System. All grounding electrodes
as described in 250.52(A)(1) through (A)(7) that are
present at each building or structure served shall be bonded
together to form the grounding electrode system. Where
none of these grounding electrodes exist, one or more of
the grounding electrodes specified in 250.52(A)(4) through
(A)(8) shall be installed and used.
Click to expand...


I believe Jumper was referring to the comment below, but didn't get in to it.

250.52 (A) (1) Metal Underground Water Pipe. A Metal underground water pipe in direct contact with the earth for more than 3.0m (10 ft.)

When was the last time that you saw an installation that was metal uderground for more than 10 feet? We constanatly bring a 250.66 sized conductor to the water pipe, even when all we really need to do is compy with "non-current carrying metal parts" bonding. Inspectors and Engineers constantly look for this bond, when it is rare today that it is required.

If I had any initiative at all, I would suggest a code change that removes this from the "Grounding electrodes" list for any structure that has a UFER. Requiring only "non-current carrying metal parts" bonding.
 
Strathead said:
I believe Jumper was referring to the comment below, but didn't get in to it.

250.52 (A) (1) Metal Underground Water Pipe. A Metal underground water pipe in direct contact with the earth for more than 3.0m (10 ft.)

When was the last time that you saw an installation that was metal underground for more than 10 feet? We constantly bring a 250.66 sized conductor to the water pipe, even when all we really need to do is comply with "non-current carrying metal parts" bonding. Inspectors and Engineers constantly look for this bond, when it is rare today that it is required.

If I had any initiative at all, I would suggest a code change that removes this from the "Grounding electrodes" list for any structure that has a UFER. Requiring only "non-current carrying metal parts" bonding.
Click to expand...

Probably over 90% of the structures in my area have metal water services that are anywhere from 25' to several hundred feet.

Even if you have a non metallic water you are still required to bond the water pipes.
 
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