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Posted By: sparkync Grounding electrode from inside subpanel?? - 02/13/09 05:53 PM
I recently changed a service from 100 amps to 200 amps. The inside panel had a ground wire going to the water pipe. This panel is not located with the mains outside. Can I leave this ground wire hooked up or do I disconnect it? I have the grounding electrode outside connectected to the Main panel outside. Thanks... Steve
For myself I will leave it and that panel become a subpanel so as long you have grouding bar in there and keep the netrual and ground seprated and the exsting EGC is there you can use it.

{ unless your local code say something diffrent then follow thier regualtions }

Merci,Marc
Metal main water pipe?
What is your main ground electrode now?
Either way, the copper water pipe must be bonded.

sounds like your ok, bond the pipe to the Subs ground.Jump the meter so you have a good bond on the house side.

250.52 addresses this.
Posted By: KJay Re: Grounding electrode from inside subpanel?? - 02/13/09 10:04 PM
Originally Posted by sparkync
I recently changed a service from 100 amps to 200 amps. The inside panel had a ground wire going to the water pipe. This panel is not located with the mains outside. Can I leave this ground wire hooked up or do I disconnect it? I have the grounding electrode outside connectected to the Main panel outside. Thanks... Steve


I think the problem might be that if it was previously 100A, then that bond to the water piping is probably only a #6 or #8 Cu.
With a 200A, it now should be at least #4, according to Table 250.66.
I would remove the old wire and run a new #4 Cu from the piping to the main panel outside. IMO, that's where it really belongs anyway.
K-Jay- hello.

At this point providing he met the proper GEC methods. Isn't this just now a bond?
Kjay is Right your grounding electroid wire at the outside 100 is probally 6 or 8.
You need a #4 for 200 amps . (250.66)
This MUST be run to the Service disconnecting means outside Not subpanel. (250.24C).
Also read (250.50)250.52)
Yoopersup
If the water main is primary, then a supplemental GE is needed.
My understanding is He has his ground (thru rods) met.Now the water need only be bonded.
250.50
ALL grounding electrodes as described in 250.52(a)1 though (a)6 that are PRESENT. shall be bonded TOGETHER to form grounding electrod system.
See 250.52 Water Underground Water pipeing.
Your only bonding the water line when less then 10ft of metal pipe is outside the building.
Again read code sections I refered to in my ist post.
Yoopersup
If its part of the Grounding Electrod system it must go to the Service disconnect or disconnect switches.
Originally Posted by Yoopersup
250.50
ALL grounding electrodes as described in 250.52(a)1 though (a)6 that are PRESENT. shall be bonded TOGETHER to form grounding electrod system.
See 250.52 Water Underground Water pipeing.
Your only bonding the water line when less then 10ft of metal pipe is outside the building.
Again read code sections I refered to in my ist post.
Yoopersup
If its part of the Grounding Electrod system it must go to the Service disconnect or disconnect switches.


Got Me Guy!!!
"..That are present...."
Up size it and bring that conductor back to the main.

Thanx for grabbing my attention to that.I got tunnel vision.
Look at 250.66 closer ... the text, not the table. You need not have a GEC larger than #6, no matter the service size.
No larger then # 6 to Ground rods but to Water lines you must go by 250.66.
250.66 (A) ground Rods
250.66 Table for Water lines.
---250.66 Table for Water lines.--

?? Confused. can't find that.
250.66
States The size of the grounding electrode conductor of a Grounded or ungrounded ac system (SHALL) not be less then given in Table 250.66 (EXCEPT) as permitted in 250.66 (A) though (C).
A = connections to Rod, Pipe, or Plate. # 6 copper
B Concrete cased electrodes # 4 copper
C Ground rings not larger then required by ground ring.
All others must compy with table such as water lines, building steel ect.\

Yoopersup
Originally Posted by leland
---250.66 Table for Water lines.--

?? Confused. can't find that.


Still??? AHH now I see what your getting at.

But he has ground rods as primary. Soo..?
I'm missing something.
250.50 (ALL) grounding electrodes as described in 250.52(A)1 though (A)6 that are present at each building or structure served (SHALL) be bonded together to form the grounding electrode SYSTEM.
250.52:
A(1) Metal underground Water pipe
(2) Metal frame of the Building
(3) Concrete encaseded Electrode
(4) Ground Ring
(5) Rod and Pipe Elewctrodes
(6) Plate Electrodes
(7) Other metal underground Systems
See examples Soares Grounding book & Nec handbook/
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