well casing grounding

Status
Not open for further replies.
K

kielarsp@alfredstate.edu

Member
guy's have this inspector who requested me to run a #4 to the well casing.
The service is a 200 amp underground with a two ground loop.Can any give
me any insight into why he would require this.




thanks guys
Steve
 
250.50 Grounding Electrode System. All grounding electrodes
as described in 250.52(A)(1) through (A)(6) 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)(7) shall be installed and used.
...
250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
...
(7) Other Local Metal Underground Systems or Structures.
Other local metal underground systems or structures
such as piping systems, underground tanks, and underground
metal well casings that are not effectively bonded to
a metal water pipe.
Click to expand...

I don't see how his request is enforcable. Metal well casings are covered in (A)(7) which is not mandatory.
 
Last edited:
Section 250.52(A)(7) of the 2005 NEC identifies a metal well casing as a suitable grounding electrode. However, section 250.50 only requires the electrodes identified in (A)(1) through (A)(6) to be bonded together to form the grounding electrode system when present.

The (A)(7) electrode is an optional electrode when none of the above are present.

1. Check the approved plans.
2. Check for any local ordinances or state laws
3. Consult the AHJ.
 
I'm curious - Why wouldn't you want to bond the well casing? It's likely the best ground you have.

My 265' well is in the single digit ohm range (depends on the time of year) - maybe three orders of magnitude better that the ground rod (500 - 3000 ohm range).

carl
 
The metal well casing needs to be bonded, size per 250.122.
If the well casing is within ten feet of the building then our state rules would consider this available and be required to be used by a GE and GEC sized per 250.66
 
I had an inspector have me do the same recently. His reason was because its the best ground available. Luckily for me the HO did the digging
 
Oakey said:
I had an inspector have me do the same recently. His reason was because its the best ground available.
Click to expand...


Don't see that as a requirement in the book. :wink:

Per NEC you are not required to use the well casing as an electrode. You can, but you do not have to.

The inspector should not be "designing" electrical systems he should be "inspecting" them.
 
coulter said:
I'm curious - Why wouldn't you want to bond the well casing?
Click to expand...

$$$

If the job was bid and completed without a GEC running to the well adding one at the end can be costly.

Put that additional cost on the tight margins dwelling units are wired for and you might just leave the black and enter the red.
 
iwire said:
$$$ ...
Click to expand...
Ah - ha. Never thought of that. When I put in my well, I put a #4 str in the ditch with the pipe, pump cable, heat trace ... Tis true - would definitely be plenty extra to go back and do it.

carl
 
Grounding a premise wiring system to a remote electrode is not only unnecessary, it may possibly create more problems than what it could ever solve.

It's like posting an "attack dog warning sign" on your neighbors property even though the dog is protecting your house...
 
tom baker said:
The metal well casing needs to be bonded, size per 250.122.
If the well casing is within ten feet of the building then our state rules would consider this available and be required to be used by a GE and GEC sized per 250.66
Click to expand...

take a look at this:

250.112 Fastened in Place or Connected by Permanent
Wiring Methods (Fixed) ? Specific.
...
(M) Metal Well Casings. Where a submersible pump is
used in a metal well casing, the well casing shall be bonded
to the pump circuit equipment grounding conductor.
Click to expand...
 
Status
Not open for further replies.
Top