"if available" bonding

[mayjong]

05 NEC
service change at a stripmall, new 800A main

1. if contractor drives a new ground rod, does existing (present)ground rod need to be bonded? (rod is approx 1' outside new switchgear.
2. if existing ground rod is "not present" (cut off @ grade?) is there a requirement to bond?

thanks!

 

[Dennis Alwon]

05 NEC
service change at a stripmall, new 800A main

1. if contractor drives a new ground rod, does existing (present)ground rod need to be bonded? (rod is approx 1' outside new switchgear.
2. if existing ground rod is "not present" (cut off @ grade?) is there a requirement to bond?

thanks!

If you meet the requirement of 25 ohms with one rod then you don't have to worry about an existing rod. However if you don't meet the 25 ohms then you would need to add another. I would not use an existing rod simply because you have no idea whether it has been cut or not. Just because the rod is there does not mean you must use it. Remember the rods must be at least 6' apart.

 

[hurk27]

05 NEC
service change at a stripmall, new 800A main

1. if contractor drives a new ground rod, does existing (present)ground rod need to be bonded? (rod is approx 1' outside new switchgear.
2. if existing ground rod is "not present" (cut off @ grade?) is there a requirement to bond?

thanks!

I agree with Dennis, there is no requirment to use any could be would be electrode, if you cant prove it meets the requirment of being an electrode, then you don't have to use it. and that requirment is "the driven rod has to have 8' of contact with Earth"

 

[barbeer]

I will inquire if 250.58 is complied with?

250.58 Common Grounding Electrode.
Where an ac system is connected to a grounding electrode in or at a building or structure, the same electrode shall be used to ground conductor enclosures and equipment in or on that building or structure. Where separate services, feeders, or branch circuits supply a building and are required to be connected to a grounding electrode(s), the same grounding electrode(s) shall be used.
Two or more grounding electrodes that are effectively bonded together shall be considered as a single grounding electrode system in this sense.

 

[mayjong]

i was thinking 250.50 "all grounding electrodes described in 250.52(A)(1) through 250.52 (A)(6) that are present... shall be bonded together to form the grounding electrode system...

1. if contractor drives a new ground rod, does existing (present)ground rod need to be bonded? (rod is approx 1' outside new switchgear.
2. if existing ground rod is "not present" (cut off @ grade?) is there a requirement to bond?

also RE:I will inquire if 250.58 is complied with?
how could it not be?

thanks!

 

[Dennis Alwon]

i was thinking 250.50 "all grounding electrodes described in 250.52(A)(1) through 250.52 (A)(6) that are present... shall be bonded together to form the grounding electrode system...

1. if contractor drives a new ground rod, does existing (present)ground rod need to be bonded? (rod is approx 1' outside new switchgear.
2. if existing ground rod is "not present" (cut off @ grade?) is there a requirement to bond?

also RE:I will inquire if 250.58 is complied with?
how could it not be?

thanks!

I stated before that because the rod was driven and is an electrode that does not mean it must be used. Must we use the well casing as an electrode or a fence post that is metal? I don't think so.

Firstly, I don't think a ground rod that is driven outside is present at the building or structure. It is present outside the structure. 250.50 states present at the structure.

 

[tom baker]

Firstly, I don't think a ground rod that is driven outside is present at the building or structure. It is present outside the structure. 250.50 states present at the structure.

But what about 250.53(A)? If driven inside per your logic it would not be in permanent moisture.

 

[Dennis Alwon]

But what about 250.53(A)? If driven inside per your logic it would not be in permanent moisture.

Not sure why one would do that but I guess if it is likely to be energized then it would need to be bonded-- not sure it would need to be part of the electrode system or not. Obviously this is a gray area but I am sure that is not the intent of the code. Cut 3" off then you don't have to worry about it if it is an 8' rod. Who knows if it is 8' anyway. :grin:

 

[mayjong]

I stated before that because the rod was driven and is an electrode that does not mean it must be used. Must we use the well casing as an electrode or a fence post that is metal? I don't think so.

Firstly, I don't think a ground rod that is driven outside is present at the building or structure. It is present outside the structure. 250.50 states present at the structure.

hmmm...
i can see the logic of the second part of this (kinda, sorta) but not the first.
isn't the rod defined as an electrode?" all grounding electrodes described in 250.52(A)(1) through 250.52 (A)(6) that are present... shall be bonded together to form the grounding electrode system..."
" shall be bonded" seems clear to me. if the rod was "present at the building" you still think it's not required to be bonded?
we (myself and the electrician) know what the existing rod is (thankfully, he is not choosing to argue that point -something i think is really stretching)
i'm surprised by your answer. semantics aside, i'm not seeing how this is supported by code. (not that i think it SHOULD be required, just that i think it IS required...)

 

[mayjong]

Not sure why one would do that but I guess if it is likely to be energized then it would need to be bonded-- not sure it would need to be part of the electrode system or not. Obviously this is a gray area but I am sure that is not the intent of the code. Cut 3" off then you don't have to worry about it if it is an 8' rod. Who knows if it is 8' anyway. :grin:

btw- i believe this is the route he is going, too... something i really don't have a problem with. still surprised by your original answer though...

also- by your logic, very few driven ground rods are "present" , as most are driven outside the building, not inside...

 

[Dennis Alwon]

I guess I don't see the purpose of requiring it. If a builder builds a structure of 3/4" rigid pipe ten feet long and drives them into the ground would we need to use this structure as an electrode. It wouldn't hurt to do so but I just don't see the code requiring it. If you have 2 rods that meet the requirements and a third is driven and not used then what's the big deal.

Do we use the well casing as an electrode?

Would you bond every fence post if the post met the definition of an electrode?

I still say at the structure is different then outside the structure. Obviously this may need clarification but I have always disconnected the old rods from old services and added my own.

 

[hurk27]

hmmm...
i can see the logic of the second part of this (kinda, sorta) but not the first.
isn't the rod defined as an electrode?" all grounding electrodes described in 250.52(A)(1) through 250.52 (A)(6) that are present... shall be bonded together to form the grounding electrode system..."
" shall be bonded" seems clear to me. if the rod was "present at the building" you still think it's not required to be bonded?
we (myself and the electrician) know what the existing rod is (thankfully, he is not choosing to argue that point -something i think is really stretching)
i'm surprised by your answer. semantics aside, i'm not seeing how this is supported by code. (not that i think it SHOULD be required, just that i think it IS required...)

To what you asked that is in red, It is only an electrode if it meets the requirements in the code of being an electrode, as I stated in my post before, if this rod has been cut off, then there is no proof of it being in contact with Earth for 8' which is what the code require for it to be an electrode. and if it cant be determined it is an electrode per definition of the NEC, then it is not required to be used, yes 250.50 requires us to use all electrodes that are available, but only if they meet the requirements of being an electrode, such as a water pipe that is not in contact 10' or more with earth is not required to be used as an electrode.

 

[hurk27]

I guess I don't see the purpose of requiring it. If a builder builds a structure of 3/4" rigid pipe ten feet long and drives them into the ground would we need to use this structure as an electrode. It wouldn't hurt to do so but I just don't see the code requiring it. If you have 2 rods that meet the requirements and a third is driven and not used then what's the big deal.

Do we use the well casing as an electrode?

Would you bond every fence post if the post met the definition of an electrode?

I still say at the structure is different then outside the structure. Obviously this may need clarification but I have always disconnected the old rods from old services and added my own.

I would say a fence is not in the list 250.52(A)(1) through (A)(6) and at most I have never seen a fence pole driven 8' in the ground and it would be hard pressed to prove it met the requirments of being an electrode. I dont think an inspector could make anyone remove anything that is already in the ground just to prove it should be used as an electrode. if it is being used as an electrode and already has a connection to it, then yes he could make you prove it qualifys as an electrode but why would they do that lol.:grin:

 

[mayjong]

To what you asked that is in red, It is only an electrode if it meets the requirements in the code of being an electrode, as I stated in my post before, if this rod has been cut off, then there is no proof of it being in contact with Earth for 8' which is what the code require for it to be an electrode. and if it cant be determined it is an electrode per definition of the NEC, then it is not required to be used, yes 250.50 requires us to use all electrodes that are available, but only if they meet the requirements of being an electrode, such as a water pipe that is not in contact 10' or more with earth is not required to be used as an electrode.

i think we are saying the same thing?
i believe the contractor will/has cut it off, and i don't have a problem with that.
if not cut, i would call it (what we ALL KNOW it is) an electrode and require bonding. i (also) don't see the purpose of requiring it (as far as the NEC goes), just have always thought it is required...
thanks for the thoughts!!!

 

[hurk27]

i think we are saying the same thing?
i believe the contractor will/has cut it off, and i don't have a problem with that.
if not cut, i would call it (what we ALL KNOW it is) an electrode and require bonding. i (also) don't see the purpose of requiring it (as far as the NEC goes), just have always thought it is required...
thanks for the thoughts!!!

Your welcome,

I look at it like this, the inspector has the burden of proof, if he want's to pull that rod to make sure it meets the NEC requirement of being an electrode, I would not stand in his way, but if he thinks I'm pounding that thing back in he's nuts:grin: