ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Al Hildenbrand - Minneapolis - obituary
by Bill Addiss - 02/03/23 07:38 PM
Violation?
by renosteinke - 01/27/23 09:52 PM
Does NEC 551.71 (F) apply to dwellings?
by BigB - 01/20/23 10:46 AM
Power submeter connections
by HotLine1 - 01/19/23 09:09 AM
New in the Gallery:
Burger King crown sillyness
Burger King crown sillyness
by wa2ise, December 11
240/208 to a house
240/208 to a house
by wa2ise, October 9
Who's Online Now
1 members (Scott35), 69 guests, and 13 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Feb 2008
Posts: 12
T
theseus Offline OP
Member
IEC 60364-4-41-2005

411.5 TT system
411.5.1 All exposed-conductive-parts collectively protected by the same protective device
shall be connected by the protective conductors to an earth electrode common to all those
parts. Where several protective devices are utilized in series, this requirement applies
separately to all the exposed-conductive-parts protected by each device.

What would happen if exposed-conductive-parts collectively protected by the same protective device be connected to different earth electrode?

Joined: Jul 2004
Posts: 9,788
Likes: 14
G
Member
You will see "ground shift" between them. "Earth" is not "zero volts" and you can see differences between ground rods that are surprisingly close together. That is why we always bond all the electrodes in a system.


Greg Fretwell
Joined: Jul 2002
Posts: 8,432
Likes: 3
Member
Greg,
I agree with the ground shift thing.
IMO, you are wasting time and materials installing Earth Electrodes any closer than about 12' apart.

One thing I have had good results with in the past, is instead of actually driving a second electrode, is clamping some stripped heavy copper wire to the electrode and burying that copper in a long thin trench at about 2' deep, this has bought down the actual earth electrode resistance and hence increased it's current-carrying capacity under fault current conditions.


Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *
2023 National Electrical Code (NEC)
2023 NEC Now Available!
 
* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Joe Tedesco
Joe Tedesco
Boston, Massachusetts USA
Posts: 2,749
Joined: October 2000
Top Posters(30 Days)
triple 3
BigB 3
Popular Topics(Views)
303,174 Are you busy
232,173 Re: Forum
216,914 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5