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Joined: Jul 2004
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G
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That mile long 2 ga neutral on the pole is not going to carry all the neutral current from the primary so some of it is going through the ground no matter what. I suppose if they used delta distribution it wouldn't be an issue but they don't. I did see delta where the transformers were L/L in Maryland but never here. They had all three primary phases on the pole. Here it is one phase and a neutral.

https://gfretwell.com/electrical/Transformer%20connections.jpg


Greg Fretwell
Joined: Sep 2002
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N
Member
I have a question, existing building has a 3-wire 1Ø feeder, which was allowed when installed, a new structure was built 29 years ago that was attached to the existing structure & a Ufer was installed in the new building but never used since the existing disconnects were left alone, fast forward almost 20 years & the original part of the building was razed in order to get proper footings & a concrete floor, a Ufer was also installed, when he existing equipment was reinstalled on the new structure, would both Ufers be required to be used? There was only a few feet between both rebar stubs so they were tied together, and it's still a 3-wire feeder, although that will change that is a advantage having a oversized UG conduit.

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G
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If the 2 Ufers were tied together in a compliant fashion, either a 30" lap for #5 (48x) or a 4ga jumper they are being used together. I would say if it was easy (AKA "available") they both need to be used but I wouldn't go to war over it..


Greg Fretwell
Joined: Jan 2005
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Cat Servant
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Here are the rules, as I understand them:
— Each lightning target requires a ground rod ( or electrode). Exception: One multi wire branch circuit (or less) needs no such electrode;
— All grounding electrodes need to be connected into the same network; and,
— These connections may be “indirect;” that is, by using the ground wire in feeder circuits.

Some examples:
— A house with a detached garage. If the garage has but one MWBC, no grounding electrode is needed. When there is a grounding electrode, you can bond that electrode to the sub-panel you have in the garage. The green wire between the sub-panel and the house panel will suffice to “connect” the electrodes into the same network;
— The cable guy drives in a little rod of his own. You need to connect his rod to yours. You can do this directly (by running a wire from his gear to the inter system connection block) or indirectly by landing his wire on the ground buss of any convenient panel; and,
— For whatever reason, you install your two rods to opposite sides of the service. You can either run your GEC from the panel to rod #1 and then on to rod #2, or you can run separate GEC’s to the ground buss of the panel.

Joined: Sep 2002
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N
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Originally Posted by gfretwell
If the 2 Ufers were tied together in a compliant fashion, either a 30" lap for #5 (48x) or a 4ga jumper they are being used together. I would say if it was easy (AKA "available") they both need to be used but I wouldn't go to war over it..


The rebar stubs up a few feet away from each other, there is a continuous piece of bare copper connecting both stubs to the main disconnect, there is no overlap between the rebar in each footing as one was poured in 1993, & the other in 2011, the Ufer in the 1993 build was never used as the panels had a ground rod as the electrode & nothing was changed then, but decided to have the Ufer since the steel was being put in the footings.

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