Steel beams bonding

[DARUSA]

If I not using the beam stell frame of the building as electrode because I have water ground+ a ground road. Wich is the maximum size wire required for bonding the steel column of the building? #4?

 

[iwire]

If I not using the beam stell frame of the building as electrode because I have water ground+ a ground road. Wich is the maximum size wire required for bonding the steel column of the building? #4?

If you have a steel building structure you do not get a choice you have to use it.

You do not need the ground rod.

As far as the size conductors we would need to know the size of the service conductors.

 

[chris kennedy]

As far as the size conductors we would need to know the size of the service conductors.

Agreed, 250.104(C).

 

[DARUSA]

If you have a steel building structure you do not get a choice you have to use it.

You do not need the ground rod.

As far as the size conductors we would need to know the size of the service conductors.

That you say is that I have to use it as electrode but we don't know if the steel is in direct contact with the earth!!! I thought that I have to only bond it to the system grounding.

 

[Dennis Alwon]

That you say is that I have to use it as electrode but we don't know if the steel is in direct contact with the earth!!! I thought that I have to only bond it to the system grounding.

It may not be a grounding electrode but look at 250.104(C)

250.104(C) Structural Metal. Exposed structural metal that is interconnected to form a metal building frame and is not intentionally grounded and is likely to become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 and installed in accordance with 250.64(A), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible.

 

[DARUSA]

It may not be a grounding electrode but look at 250.104(C)

That's like saying that I will have to run the same size as the cold water Ground wire!!!!! But if i bond it to a Ground road with#6. A#4 wire will be Ok?!!!!!

 

[Volta]

That's like saying that I will have to run the same size as the cold water Ground wire!!!!! But if i bond it to a Ground road with#6. A#4 wire will be Ok?!!!!!

As Iwire said, you are not required to install the rod if the steel is an electrode. If you can't know that it is, the rod(s) should augment the underground water pipe. The steel will be connected either way. If a #4 is sufficient for the water, then it is ok for the steel too.

The ground rod(s) can be / must be bonded to the steel, as it is part of the Grounding Electrode System, whether or not it is otherwise intentionally connected to the earth 250.52(A)(2)(3). Catch 22.

 

[Dennis Alwon]

#4 will work if you have a 200 amp service. The gec is based on T250.66.

You cannot bond he steel directly to the ground rod if the ground rod has a #6. The building steel will have to tie to the water pipes or to the service panel.

 

[cripple]

Steel beams bonding

Section 250.66(A) where the grounding electrode conductor or bonding conductor and that the conductor is the sole connection to system, is not required to be larger than a 6 AWG. Now, if the conductor from the ground rod is connected to the system or service neutral conductor, you have met this requirement, but not if you bond the ground rod to the building steel or cold water piping system.
The grounding electrode conductor or bonding jumper to building steel is required to be sized per 250.66 based on the cross-sections area of the conductor at the service, the disconnect supplying each building or structure by a feeder, or the secondary conductors of a separately derived system.

 

[DARUSA]

Section 250.66(A) where the grounding electrode conductor or bonding conductor and that the conductor is the sole connection to system, is not required to be larger than a 6 AWG. Now, if the conductor from the ground rod is connected to the system or service neutral conductor, you have met this requirement, but not if you bond the ground rod to the building steel or cold water piping system.
The grounding electrode conductor or bonding jumper to building steel is required to be sized per 250.66 based on the cross-sections area of the conductor at the service, the disconnect supplying each building or structure by a feeder, or the secondary conductors of a separately derived system.

Ok but my water ground is going to be connected to the neutral at the service , my ground rod and the steel column will be attached to my grounding bar.just to tie all in the same point!!!! + the main bonding jumper!!!

 

[Dennis Alwon]

Ok but my water ground is going to be connected to the neutral at the service , my ground rod and the steel column will be attached to my grounding bar.just to tie all in the same point!!!! + the main bonding jumper!!!

Are you saying that the grounding bar (What is this exactly) is not tied to the neutral bar-- they usually are the same in the service.
Thus your water bond goes back to the neutral at the service along with the steel bond and ground wire. The water line, as an electrode must be continuous to the service.


The picture says it better than I do. Notice that the ground rod does not have any larger bond wires attached to it. You could jump from one rod to the other but not from the rod to the building steel. Assuming a service 200 amps or greater--

 

[DARUSA]

yes dennis but a supplementary grounding bar is allowed too
Take a look 250.64 C

 

[DARUSA]

Look this picture

 

[DARUSA]

Are you saying that the grounding bar (What is this exactly) is not tied to the neutral bar-- they usually are the same in the service.
Thus your water bond goes back to the neutral at the service along with the steel bond and ground wire. The water line, as an electrode must be continuous to the service.


The picture says it better than I do. Notice that the ground rod does not have any larger bond wires attached to it. You could jump from one rod to the other but not from the rod to the building steel. Assuming a service 200 amps or greater--

Let say that this is 4000 amps service:
#1 is based on the table 250.66,
#2 maximum size required is a #4 wire,
#3 Maximun size required #4 250.66 B
#5 Maximun size required #6 wire 250.66 A
Correct me if i'm wrong please!! to help me

 

[DARUSA]

yes dennis but a supplementary grounding bar is allowed too
Take a look 250.64 C

Sorry the code section is 250.64 F 3

 

[Dennis Alwon]

I was just checking to see if I understood what you were doing. I thought you may be going to a ground bar in a sub panel. Remember I have no idea what you do know and I wanted to be sure you were doing the right thing.

You steps in the post above sound right to me.

 

[DARUSA]

I was just checking to see if I understood what you were doing. I thought you may be going to a ground bar in a sub panel. Remember I have no idea what you do know and I wanted to be sure you were doing the right thing.

You steps in the post above sound right to me.

Clearly How do i size My bonding jumper to the column steel? . The # 4 is ok or I should be run a 3/0 wire based on the table 250.66 for a 4000 amps service.
I have learned a lot thanks to all you guys here in this forum!!!

 

[Volta]

Clearly How do i size My bonding jumper to the column steel? . The # 4 is ok or I should be run a 3/0 wire based on the table 250.66 for a 4000 amps service.
I have learned a lot thanks to all you guys here in this forum!!!

I read 250.104(C) as requiring exposed structural building frame metal to be bonded with a jumper sized per 250.66, so a 3/0 in this case.
It then automatically becomes part of the electrode system.

Let say that this is 4000 amps service:
#1 is based on the table 250.66,
#2 maximum size required is a #4 wire,
#3 Maximun size required #4 250.66 B
#5 Maximun size required #6 wire 250.66 A
Correct me if i'm wrong please!! to help me

So I would change #2 to a 3/0 jumper.

 

[Dennis Alwon]

I read 250.104(C) as requiring exposed structural building frame metal to be bonded with a jumper sized per 250.66, so a 3/0 in this case.
It then automatically becomes part of the electrode system.

So I would change #2 to a 3/0 jumper.

Yes sorry I missed that... It should be 3/0

 

[cadpoint]

I see a lot more of the illustration that was shown in thread #13, thanks for breaking down the differences.