250.68(C)(3)

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augie47

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Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
In the '17 Code the wording in 268.(C)(3) states "an additional rebar extended from its location in the concrete to an accessible location that is not subject to corrision....."
In this area it is practice to use a galvanized ground rod bent to tie to the concrete encased re-bar and terminate outside the footer. Since connector used is rated "DB" is it permissible to make that connection in in the earth or would 268.(C)(3) prohibit that ?
 

Mouser

Member
Location
Riverside, CA.
the comments in the handbook may be of value.

"If rebar is used to form the concrete-encased electrode, it is permitted to
extend out of the concrete to an accessible location for connection to a
grounding electrode conductor or bonding jumper. Contact between
unprotected rebar and earth can cause corrosion and is prohibited. Over
time this corrosion will deteriorate the rebar and eliminate the connection
to the electrode in the concrete."

My take on your question, since your using a galvanized ground rod you should be fine.
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
In the '17 Code the wording in 268.(C)(3) states "an additional rebar extended from its location in the concrete to an accessible location that is not subject to corrision....."
In this area it is practice to use a galvanized ground rod bent to tie to the concrete encased re-bar and terminate outside the footer. Since connector used is rated "DB" is it permissible to make that connection in in the earth or would 268.(C)(3) prohibit that ?

Is a buried location both "accessible" and "not subject to corrosion"? If both answers are yes, it is allowed; if either answer is no, it is prohibited.

While the last sentence of 2017 250.68(C)(3) allows the galvanized rebar to be in contact with the earth, it does not explicitly provide relief from the requirement that the connection occur in a location that is "accessible" and "not subject to corrosion".

BTW, I don't think structural engineers would like having rebar exiting the foundation into the earth, even if it is galvanized. I'll have to ask a structural engineer the next time I run into one.

Cheers, Wayne
 
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