Supplemental rod electrode-2011

[TODD B.]

According to the 2011 NEC, ARTICLE 250 SECTION 250.53(A) states that a rod,pipe or plate electrode is to be supplemented by an additional electrode. Does this mean that if only a rod,pipe or plate electrode that serve a building or structure as the only electrode that an additional electode is to be installed if 25 ohms or less cannot be met. Or, if supplemental; to say a water line bond, that still two grounds rods are required to be driven if 25 ohms or less cannot be met.

 

[raider1]

According to the 2011 NEC, ARTICLE 250 SECTION 250.53(A) states that a rod,pipe or plate electrode is to be supplemented by an additional electrode. Does this mean that if only a rod,pipe or plate electrode that serve a building or structure as the only electrode that an additional electode is to be installed if 25 ohms or less cannot be met.

That is correct, if the grounding electrode system consists of a single ground rod, pipe or plate then that electrode must be supplemented by additional electrode unless the single electrode has a resistance of 25 ohms or less.

Or, if supplemental; to say a water line bond, that still two grounds rods are required to be driven if 25 Ohms or less cannot be met.

Correct, if you are supplementing a water pipe electrode with a rod, pipe or plate electrode then the supplemental electrode must also be supplemented with an additional electrode if it does not have a resistance of 25 Ohms or less.

Chris

 

[Buck Parrish]

I agree with Chris and will add it's in the same location in 08 as in 11 - NEC 250.53(d)2

 

[TODD B.]

Thanks guys, it always helps to get additional input from others.Sometimes the NEC can be difficult to decipher.

 

[muskrat]

That is correct, if the grounding electrode system consists of a single ground rod, pipe or plate then that electrode must be supplemented by additional electrode unless the single electrode has a resistance of 25 ohms or less.




Correct, if you are supplementing a water pipe electrode with a rod, pipe or plate electrode then the supplemental electrode must also be supplemented with an additional electrode if it does not have a resistance of 25 Ohms or less.

Chris

Last paragraph-aren't you proposing to supplement a supplemental elecrode with a supplemental electrode which must also be supplemented? Where does it end? JK but it is cofuseing as posted.

 

[raider1]

Last paragraph-aren't you proposing to supplement a supplemental elecrode with a supplemental electrode which must also be supplemented? Where does it end? JK but it is cofuseing as posted.

Let me simplify it.

If you have a metal water pipe and use ground rods to supplement it you have to use 2 ground rods.

Chris

 

[TODD B.]

Let's say for example we have a dwelling unit that has metallic water line entering the building and we bond the water line within 5', we also need to supplement that water line bond and we drive a ground rod. What 250.53 (a) leads me to believe in this situation is that i need to drive another ground rod (6' apart) if 25 ohms cannot be achieved. That's what seems to be what 250.53 (a) is saying.

 

[tom baker]

Thanks guys, it always helps to get additional input from others.Sometimes the NEC can be difficult to decipher.

If it was easy to decipher then there would be no Mike Holt Code Forum and I would not have anything to do at lunch.

 

[Dennis Alwon]

Let's say for example we have a dwelling unit that has metallic water line entering the building and we bond the water line within 5', we also need to supplement that water line bond and we drive a ground rod. What 250.53 (a) leads me to believe in this situation is that i need to drive another ground rod (6' apart) if 25 ohms cannot be achieved. That's what seems to be what 250.53 (a) is saying.

We can say it a million ways but you are correct. Generally it is not possible to get 25 ohms with one rod so we automatically assume 2 rods. Now if you use a concrete encased electrode you still need to connect to the metallic water line but you do not need the ground rods.

Also,, if there is plastic coming in from the street and metallic in the house then we still need to bond the water line but this may be done anywhere on the piping system. Confused yet---:grin:

 

[inspector 102]

Since Section III of Article 250 says that a grounding electrode system is required, and 250.52(A)(3) refers to the CEE as simply an electrode, does an additional grounding electrode need to be added to create the system? Simply put - if using a UFER ground, do you still need to augment with ground rods?

 

[raider1]

Since Section III of Article 250 says that a grounding electrode system is required, and 250.52(A)(3) refers to the CEE as simply an electrode, does an additional grounding electrode need to be added to create the system? Simply put - if using a UFER ground, do you still need to augment with ground rods?

Nope.

Chris