Nec 250.24(A)(1)

[hhsting]

NEC 2017 section 250.24(A)(1) the grounding electrode conductor connection shall be made at any accessible point from load end of the overhead service conductors, service drops, unground service conductors, or service lateral to including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means.

My question is lets say grounding electrode conductor is made at service disconnecting means and its a 2000A 480/277V three phase switchboard. This mean that the grounding electrode conductor needs to be connected to neutral bar. Does this mean one needs to drill neutral bar to connect grounding electrode conductor or not? Does anyone know?

 

[don_resqcapt19]

What would permit you to drill the neutral bar. You simply land the GEC on one of the neutral terminals.
Also I would expect that size equipment has a bus type main bonding jumper which permits you to land the GEC on the EGC bus. See 250.24(A)(4).

 

[jim dungar]

UL listed service entrance equipment has the neutral to ground bonding done by the factory or provisions for field bonding must be provided.

 

[hhsting]

UL listed service entrance equipment has the neutral to ground bonding done by the factory or provisions for field bonding must be provided.

Question has nothing to do with neutral to ground bond. Its about grounding electrode conductor connection. Please see post #1

 

[don_resqcapt19]

Question has nothing to do with neutral to ground bond. Its about grounding electrode conductor connection. Please see post #1

Please read the section I cited because it has everything to do with the neutral to ground bond.

 

[augie47]

I can't imagine that actually being a field problem. I've seen 100 or so 1,000 + amp switchboards and all have had lugs available for the GEC on the neutral or equipment ground bar or, in rare cases, a factory hole where you can add a lug

 

[jim dungar]

Question has nothing to do with neutral to ground bond. Its about grounding electrode conductor connection. Please see post #1

Your post clearly mentions neutral and grounding provisions. My answer says UL Listed equipment have the required provisions for both grounding and neutral connections.

 

[electrofelon]

Does this mean one needs to drill neutral bar to connect grounding electrode conductor or not? Does anyone know?

Neutral bar should have proper provisions for the GEC. The installing electrician should take care of it, and the inspector in the field can raise any objections. Not sure what a plan reviewer would have to do with this.

 

[hhsting]

Neutral bar should have proper provisions for the GEC. The installing electrician should take care of it, and the inspector in the field can raise any objections. Not sure what a plan reviewer would have to do with this.

Well attached sketch of main service grounding electrode system it looks like grounding electrode conductor from external bus bar to the main service switchboards is going to enclosure where then it goes to another conductor which then connects to neutral bar. Its strange but I thought GEC either go to neutral bar or equipment grounding conductor without splice at main service disconect??

 

[don_resqcapt19]

The code permits the various grounding electrode conductors to be connected to a grounding bus as shown in that drawing. 250.64(F)(3)

The engineer has specified conductors from the grounding electrodes that are larger than what the code requires. The largest size the code requires is 3/0 copper.

 

[hhsting]

The code permits the various grounding electrode conductors to be connected to a grounding bus as shown in that drawing. 250.64(F)(3)

The engineer has specified conductors from the grounding electrodes that are larger than what the code requires. The largest size the code requires is 3/0 copper.

Look at the grounding electrode from external bus bar to main switchboard. Inside the main switchboard where the grounding electrode conductor connects there is a dot meaning there is joint or splice connection.

The grounding electrode conductor goes inside corner of main service switchboard and then connects to another conductor which then connects to neutral bus. There are total two dots in main service switchboard one on neutral bus and another where GEC connects these are joints or splice


I thought grounding electrode conductor need to connect directly to neutral bus without above splice or joint?

 

[MyCleveland]

Look at the grounding electrode from external bus bar to main switchboard. Inside the main switchboard where the grounding electrode conductor connects there is a dot meaning there is joint or splice connection.

The grounding electrode conductor goes inside corner of main service switchboard and then connects to another conductor which then connects to neutral bus. There are total two dots in main service switchboard one on neutral bus and another where GEC connects these are joints or splice


I thought grounding electrode conductor need to connect directly to neutral bus without above splice or joint?

I believe the “dot” at the entrance to each switchboard is a drafting error.

Where is the third switchboard? ….3 of 3?
Does plan have a third?

 

[Greentagger]

Refer to 250.24(A)(4).

 

[jim dungar]

According to UL the GEC is connected to the switchboard ground bus not the neutral. See neutral and ground definitions in:

https://code-authorities.ul.com/wp-content/uploads/2014/04/DFSwitchboard_MG.pdf

 

[acin]

Well attached sketch of main service grounding electrode system it looks like grounding electrode conductor from external bus bar to the main service switchboards is going to enclosure where then it goes to another conductor which then connects to neutral bar. Its strange but I thought GEC either go to neutral bar or equipment grounding conductor without splice at main service disconect??

250 66 largest cu gec shows 3/0 ?

 

[MyCleveland]

According to UL the GEC is connected to the switchboard ground bus not the neutral. See neutral and ground definitions in:

https://code-authorities.ul.com/wp-content/uploads/2014/04/DFSwitchboard_MG.pdf

Sketch 2.1 states you can connect to either N or EG bus.
Is this not better to teach where the GFP sensors come into play and why that section of bus jumps ahead of sensors.

 

[don_resqcapt19]

Look at the grounding electrode from external bus bar to main switchboard. Inside the main switchboard where the grounding electrode conductor connects there is a dot meaning there is joint or splice connection.

The grounding electrode conductor goes inside corner of main service switchboard and then connects to another conductor which then connects to neutral bus. There are total two dots in main service switchboard one on neutral bus and another where GEC connects these are joints or splice


I thought grounding electrode conductor need to connect directly to neutral bus without above splice or joint?

Just because the drawings seem to show an connection between the GEC and the enclosure, does not mean that the GEC has been cut at that point. There are connectors that permit that connection without cutting the conductor.
This is just not an issue that should be looked at in the plan review. Those connections are an issue for the installation inspection.

 

[hillbilly1]

Yeah, the engineer has oversized the GEC, especially to the ground rods, but nothing in code says he can’t, but it shows he is good at copy and paste! LOL!

 

[rc/retired]

Yeah, the engineer has oversized the GEC, especially to the ground rods, but nothing in code says he can’t, but it shows he is good at copy and paste! LOL!

Bingo! Most of the electrical plans I reviewed were, what do you call them, boiler plate, stamped, etc. They pretty much showed the same grounding 1 line.

 

[hhsting]

Just because the drawings seem to show an connection between the GEC and the enclosure, does not mean that the GEC has been cut at that point. There are connectors that permit that connection without cutting the conductor.
This is just not an issue that should be looked at in the plan review. Those connections are an issue for the installation inspection.

Ok but just curious what sort if connectors? Do these connectors bond the GEC to the enclosure as well?