ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by gfretwell - 03/28/24 12:43 AM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
1 members (Scott35), 269 guests, and 18 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#84466 04/02/03 09:18 PM
Joined: Feb 2002
Posts: 840
C
Member
(This is a carry over from the Mike Holt forum on the same topic.)

Here is a common situation. A residence has a 400 amp service. It is a rural setting, so there is no metallic water main and meter into the house. (It is plastic coming from the well pump). The only metalic piping is the interior water system.

In this situation, the GEC to the made electrode is not required to be larger than #6, correct? Or must it be #2 copper (assuming 3/0 copper parallel for the service), since there is no metallic water main?

It is my understanding that the only purpose of the ground rod is to direct lighting strikes to ground.

-Peter



[This message has been edited by CTwireman (edited 04-02-2003).]


Peter
Stay up to Code with the Latest NEC:


>> 2023 NEC & Related Reference & Exam Prep
2023 NEC & Related Reference & Study Guides

Pass Your Exam the FIRST TIME with the Latest NEC & Exam Prep

>> 2020 NEC & Related Reference & Study Guides
 

#84467 04/02/03 11:58 PM
Joined: Dec 2001
Posts: 270
E
Member
Yup, just #6 to the ground rod..per 250.66(A).

I know that some would increase the size to #2 if there were two rods installed. The idea is that a rod can only disperse so much current in a given time. Two rods can disperse twice as much current as one, so the GEC ought to be doubled in ampacity as well (in spite of what the wording of 250.64(F) says). Thus #1.
Yet, the code only requires a maximum GEC size of #2 for parallel 3/0.

[This message has been edited by Elzappr (edited 04-02-2003).]

#84468 04/03/03 07:25 AM
Joined: Feb 2003
Posts: 198
Z
Member
CT,- We basicly have the same common here in the rural areas. Our POCO will not allow us to install our GEC in the meter socket, so for a 320 service, we install one GEC, usually a #4 from each panelboard or disconnect to one rod each tail under its own acorn clamp. Then to bond the plumbing, we use #4.


Shoot first, apologize later.....maybe
#84469 04/03/03 08:22 AM
Joined: Jul 2001
Posts: 37
R
Member
zapped
A #4 to the piping on a 320 amp service? Shouldn't the H20 bond sized to the service entrance conductor size?
Rick

#84470 04/04/03 07:44 AM
Joined: Feb 2003
Posts: 198
Z
Member
RickG,- Yes you are correct, but due to the fact that the outside water piping is plastic from the well head ,our main electrode is the rod. In town where copper water service is present then we bond accordingly.


Shoot first, apologize later.....maybe
#84471 04/04/03 12:16 PM
Joined: Nov 2000
Posts: 2,148
R
Member
Zapped,
The bonding conductor for the interior metal water piping system is sized per Table 250.66 even when the water service to the building is nonmetallic. See 250.104(A).
Don


Don(resqcapt19)

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5