concrete encased electrode
- Thread starter eem946
- Start date
- Status
- Location
- Massachusetts
As many as you got.
- Location
- Logan, Utah
Welcome to the forum.
A concrete encased electrode is designed to make a connect to the earth for the premise electrical system. The connection to the earth is to stabilize the voltage to earth during normal operations and to help limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines. The concrete encased electrode is not intended to carry any kind of fault current.
Chris
A concrete encased electrode is designed to make a connect to the earth for the premise electrical system. The connection to the earth is to stabilize the voltage to earth during normal operations and to help limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines. The concrete encased electrode is not intended to carry any kind of fault current.
Chris
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Look at 250.52(A)(3). This means that the CEE never has to be larger than #4 copper no matter what size service you have. You can use a larger conductor but it is not required.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
- Location
- Logan, Utah
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
Galvanic reaction?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
???????-- it is required by code to tie to the rebar. :-? I assume that is not an issue since we attach copper to galvinized rods all the time.
- Location
- Massachusetts
Dennis I am not sure if we are required to connect to the steel if we have 20' of 4 AWG in the cement but that said I have seen it argued both ways with no clear cut answer.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I read it as an either/or. No attachment required if you have the 20' of bare copper.
- Location
- Logan, Utah
- Location
- Massachusetts
Is twenty feet of 4 AWG in a concrete footing an electrode?
Is twenty feet of 1/2" re-bar in a concrete footing an electrode?
Now what does 250.50 say?
Just pointing it out ........... :grin:
Is twenty feet of 1/2" re-bar in a concrete footing an electrode?
Now what does 250.50 say?
Just pointing it out ........... :grin:
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I agree-- My intent was to state that touching it doesn't matter if we are required to tie to the rebar-- if we choose.
I am glad to caught that as others may have thought the rebar was required. The only time I wouldn't connect to the rebar is if the rebar wasn't in the footer. Even if it was smaller than 1/2" (I have not seen that) I would run 20' and connect to the rebar. But that's me--
- Location
- Logan, Utah
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
It's my knee-jerk chemical engineer reaction. Without commenting on the code, tieing the copper directly to the steel or zinc in a damp environment creates a battery which will result in the rapid destruction of the zinc or steel. The interior of all concrete structures in contact with the ground will contain some moisture, so you'll always get corrosion in such cases.
- Location
- Logan, Utah
After discussing this with a member of CMP 5, I was told that galvanic action is not an issue with copper and steel embedded in concrete.
Chris
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
One could also argue that the rebar trumps the 20' of #4 simply because the rebar (an electrode) is present and therefore it must be used.
- Location
- Logan, Utah
They would both constitute an electrode and I don't think either one would trump the other.
Chris
- Status