Continuous GEC

[slc410]

We have a situation where we have a 400 amp service on a commercial building which is a ct cabinet on the exterior and two 200 amp main disconnect panels on the interior fed parallel each with feeders from the ct cabinet. Does the grounding electrode conductor have to run continuous from the rods through the first panel and then to the second or can it land on the ground bar in the first then another wire from that same bar to the second?

 

[infinity]

ct cabinet on the exterior and two 200 amp main disconnect panels on the interior fed parallel each with feeders from the ct cabinet.

You said feeders, is there an OCPD at the CT cabinet or do the service conductors go to each panel? If the POCO allows you can bring the GEC directly to the CT cabinet.

 

[jaggedben]

We have a situation where we have a 400 amp service on a commercial building which is a ct cabinet on the exterior and two 200 amp main disconnect panels on the interior fed parallel each with feeders from the ct cabinet. Does the grounding electrode conductor have to run continuous from the rods through the first panel and then to the second or can it land on the ground bar in the first then another wire from that same bar to the second?

I'm going to assume you misnamed the service entrance conductors between the CT cabinet and panels as feeders, and the panels are the service equipment.

You are not supposed to run a grounding electrode conductor through one service panel to another, continuous or not. You either run separate GECs or GEC taps. See 250.64(D).

 

[slc410]

I'm going to assume you misnamed the service entrance conductors between the CT cabinet and panels as feeders, and the panels are the service equipment.

You are not supposed to run a grounding electrode conductor through one service panel to another, continuous or not. You either run separate GECs or GEC taps. See 250.64(D).

Very sorry, service feeds. If we do the tap method, does the tap need to be accessible and can it be split bolted or does it need to be irreversible?

 

[jaggedben]

It can be split bolted. (Assuming the split bolt is a listed grounding and bonding connector, but I believe they usually are.)

 

[Fred B]

Very sorry, service feeds. If we do the tap method, does the tap need to be accessible and can it be split bolted or does it need to be irreversible?

250.24(C) requires the main bonding jumper to be unspliced or done with an irreversable splice connection. So question is where is you N/G bonding occurring? If each panel has a seperate service feed Each panel will have a main bonding jumper but all electrodes of a single structure must be connected to create a single GES. That does not need to be made up with irreversible splices.
Seen large apt that had 2 service connections on opposite sides of building. Each side had it's own GE's but they also had to be interconnected to create a single GES (250.50)

 

[infinity]

Very sorry, service feeds. If we do the tap method, does the tap need to be accessible and can it be split bolted or does it need to be irreversible?

As stated the "tap" method allows the use of split bolt since the "taps" are not a GEC, they are bonding jumpers. Only a splice in the GEC requires irreversible connectors. You would size the GEC using the conductor size to the CT cabinet and the "taps" according to the conductor size of each service disconnect.

 

[Fred B]

As stated the "tap" method allows the use of split bolt since the "taps" are not a GEC, they are bonding jumpers. Only a splice in the GEC requires irreversible connectors. You would size the GEC using the conductor size to the CT cabinet and the "taps" according to the conductor size of each service disconnect.

View attachment 2570567

Picture says a thousand words. Picture is quit clear as to what is happening but in practice this layout can be less clear and careful viewing of the entire system becomes tougher to determine the GEC vs Taps.
Don't want inspector to call out, make sure the ability to discern the actual GEC vs Tap is very clear. Simplest would be landing GEC onto a bus that the Taps can land onto.

 

[infinity]

Simplest would be landing GEC onto a bus that the Taps can land onto.

IMO the simplest way would be the run the GEC to the first panel and tap off the GEC above or below the panel to the second panel with a split bolt.

 

[letgomywago]

IMO the simplest way would be the run the GEC to the first panel and tap off the GEC above or below the panel to the second panel with a split bolt.

Depending on how many. When doing 320 services with 2 200 amp panels I liked looping through the ufer and then using only 1 connector.

 

[jaggedben]

Yeah, you should really run the GEC past all the panels to the *last* one, then tap to the ones you passed by.

 

[slc410]

Thank you all for helping in clarifying this situation. My last point to bring about is in sizing the grounding electrode conductor going to the rod type grounding electrodes 250.66 (A) reads if the gec does not extend to other types of electrodes the size that can be used does not need to be larger than #6. Is this the case for my application? Also then say hypothetically that I had a metal underground water pipe enter the building (I don't) does the wording in 250.66 (A) require me to size the gec to the rods to be sized to table 250.66 like the water electrode? This is confusing to me

 

[augie47]

You would only need to increase the size of the conductor to the rods if you extended the conductor to another electrode requiring a larger wire.
In other words, it could not be considered a weak link in the chain

 

[LarryFine]

You may not use #6 anywhere in a pathway that requires a larger conductor. In other words, if you were to daisy-chain electrodes, the section to the rod should be last if you want to use #6 for it.

 

[infinity]

With the exception of two ground rods and water meter I'm not a big fan of creating a massive loop with the GEC. I say a job where they ran the GEC to the water pipe jumped over the meter went out of the house ran to two ground rods and then for some unknown reason back to the panel. When I asked the electrician why he did it that way he said that he didn't want to have to irreversibly splice the GEC.

 

[electrofelon]

With the exception of two ground rods and water meter I'm not a big fan of creating a massive loop with the GEC. I say a job where they ran the GEC to the water pipe jumped over the meter went out of the house ran to two ground rods and then for some unknown reason back to the panel. When I asked the electrician why he did it that way he said that he didn't want to have to irreversibly splice the GEC.

I am not really sure why as it is pretty clearly laid out in 250.65, but many electricians really struggle with how to run the GEC for services with multiple disconnect enclosures. I see all sorts of looping methods, probably more often then the tap method.

 

[electrofelon]

I am not really sure why as it is pretty clearly laid out in 250.65, but many electricians really struggle with how to run the GEC for services with multiple disconnect enclosures. I see all sorts of looping methods, probably more often then the tap method.

Typo: 250.64, specifically (D)

 

[slc410]

I think where people get confused is the "continuous" verbage. I think everyone believes the GEC cannot be tapped and must be a continuous wire ran to all service disconnects

 

[Doc13067]

I love using the C Taps for this. They’re on Amazon for like $4.

 

[letgomywago]

I love using the C Taps for this. They’re on Amazon for like $4.

The crimper for those are available on ebay too used for a decent price