ECN Forum
Posted By: beach bonding ground - 02/13/02 04:34 AM
A friend of mine is adding on to his house. He relocated his main and installed a ufer. Currently he is not bonded to his water pipes and AHJ has not said anything.
What kind of bond should he run and from where. At the ufer connection or from the busbar. To add to this, his water main comes up in galv 2 feet to a shutoff valve then to a dielectric union then to copper. Should he bond to both the galv and copper. This is an older house and I know much of his recp are bonded to the water pipes.
Posted By: sparky Re: bonding ground - 02/13/02 10:47 AM
beach,
IMO, a UFER correctly done, is superior to a municipal H2O pipe, and much less a potential nuetral.
However, the NEC would like the H2O pipe ( mettalic) used as a GEC, so i would size to 250.66, run it over , connect to the CU side & leave a tail long enough to connect to the galvy side if required.
hint, get yer amprobe ready when ya do....
[Linked Image]
Posted By: Redsy Re: bonding ground - 02/13/02 12:18 PM
I'd go from the service panel to the UFER with a properly sized GEC. Then go from the UFER to the water line on the supply side of the valve, and to the copper side of the di-electric union.
Posted By: Electricmanscott Re: bonding ground - 02/13/02 12:45 PM
Maybe its me....but what the heck is a ufer? Is this what the kids used to call refer?Anyway I would run my grounding electrode conductor to the water pipe and attach to the galvi and then to the copper just for a little extra security. Is the there a water meter there? I would also run a #6 cu to a ground rod to suplememnt the main water pipe ground. These would both originate at the service entrance panel or disconnect.
Posted By: beach Re: bonding ground - 02/13/02 01:19 PM
What does "ufer" stand for anyway.
Thank you for your responses.

Jon
Posted By: safari Re: bonding ground - 02/13/02 03:48 PM
250.50 requires all systems in 250.52.A.(1-6) to be used if available,it appears that you have 250.52.A.3 as you have a "EUFER" (the name of the engineer who spent many years studying grounding and grounding systems)as for 250.52.A.1 it only applys if you can show that there exists more than 10' of metal in the ground not just a galvanized riser on underground plastic pipe.
In addition section 250.104 requires Bonding.
250.104.A would require the interior water piping to be bonded, and 250.104.B would require any other metal piping systems to be bonded.
Posted By: sparky66wv Re: bonding ground - 02/13/02 04:03 PM
A Ufer is specifically a concrete-encased electrode... Almost as elaborate as an equipotential plane... (Actually, they look like the same thing to me)

Herbert G. Ufer was the inventor's name.

Go here:
http://www.scott-inc.com/html/ufer.htm
Posted By: dana1028 Re: bonding ground - 02/13/02 11:54 PM
Beach - for simplicity (Ufer) - it is a piece of rebar bent upwards (i.e. coming out of the poured concrete footing/foundation) - this piece of rebar is usually placed pretty close to your main panel so it is easy to bond the panel to (using a #4 copper conductor)...see 250-66(b)- "Concrete Encased Electrodes" is referring to a Ufer (as above named after the inventor of this system)....do check out the link above as it gives some good history behind this system.
Posted By: resqcapt19 Re: bonding ground - 02/14/02 12:50 AM
Sparky
Quote
IMO, a UFER correctly done, is superior to a municipal H2O pipe...

If the Ufer is superior to a metal underground water piping system for use as a grounding electrode, why does the code require a full sized (per Table 250-66) grounding electrode conductor to the water pipe and only a #4 to the Ufer?
Don(resqcapt19)
Posted By: Bill Addiss Re: bonding ground - 02/14/02 12:53 AM
beach,

When you say that most receptacles are bonded to the water pipe does that mean there is no ground wire in the branch circuit wiring to the receptacles? Did someone replace 2 prong outlets with 3 prong along the way and run separate grounding conductors to the waterpipe?

Bill
Posted By: motor-T Re: bonding ground - 02/14/02 01:27 AM
Beach:
The story I read about the Ufer ground was an engineer whose First name was Herbert and he did alot of work during the Second World War, on Ammo dump installations and had trouble getting good grounds in sandy areas ie Parts of California and primarily out west and hit upon the concrete encased electrode, he found the resistance to ground in this form was consistant over time, ergo the 'ufer ground' was born.
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