tx2step
Senior Member
- Location
- North Texas, DFW area
We're currently under the 2002 code, but will be moving to the 2014 before long.
250.50 requires the first 6 types of electrodes [250.52(A)(1) thru (A)(6)] to be used "If available on the premises..."
Of the first 3 types:
1. UG water pipe:
(a) This appears to me to be a required electrode, if it exists...right? You can't choose not to use it?
(b) It must be supplemented by at lease one additional type of electrode, right? 250.53(D)(2)?
2. metal building frame:
(a) This appears to me to be a required electrode, if it exists...right? You can't choose not to use it?
(b) Does this have to be supplemented by any other electrode? Or is it sufficient alone?
(b) Do you ever have to test it to see if it's really working? If so, how do you usually have to test it? What would be an acceptable resistance?
3. concrete-encased electrode:
(a) For new construction with rebar in the foundation/footings, is this a "required" electrode? Or can you choose not to have a concrete-encased electrode, even if the new footings would qualify as one if they are connected?
(b) If it's used, does it have to be supplemented by any other electrode? Is it sufficient alone?
(c) Do you ever have to test it to see if it's really working? If so, how do you usually have to test it? What would be an acceptable resistance?
For ground rods (250.56) do you always just install a second one at lease 6' apart? Of do you usually demonstrate that a single one is under 25 ohms?
I want to see how the grounding electrode requirements are generally interpreted/implemented in other parts of the country.
Thanks!!!
250.50 requires the first 6 types of electrodes [250.52(A)(1) thru (A)(6)] to be used "If available on the premises..."
Of the first 3 types:
1. UG water pipe:
(a) This appears to me to be a required electrode, if it exists...right? You can't choose not to use it?
(b) It must be supplemented by at lease one additional type of electrode, right? 250.53(D)(2)?
2. metal building frame:
(a) This appears to me to be a required electrode, if it exists...right? You can't choose not to use it?
(b) Does this have to be supplemented by any other electrode? Or is it sufficient alone?
(b) Do you ever have to test it to see if it's really working? If so, how do you usually have to test it? What would be an acceptable resistance?
3. concrete-encased electrode:
(a) For new construction with rebar in the foundation/footings, is this a "required" electrode? Or can you choose not to have a concrete-encased electrode, even if the new footings would qualify as one if they are connected?
(b) If it's used, does it have to be supplemented by any other electrode? Is it sufficient alone?
(c) Do you ever have to test it to see if it's really working? If so, how do you usually have to test it? What would be an acceptable resistance?
For ground rods (250.56) do you always just install a second one at lease 6' apart? Of do you usually demonstrate that a single one is under 25 ohms?
I want to see how the grounding electrode requirements are generally interpreted/implemented in other parts of the country.
Thanks!!!