Grounding for Single Ph 120/240 400 Amp Service

[super dave]

I was hoping to get some advise for a service upgrade that I plan to do soon. I need to upgrade from a 200 amp to a 400 amp service. I plan to install the POCO 400 amp meter base and then connect 2- 200 amp disconnects in parrallel. My question is the termination of the GEC. There is a lug in the meter base, however I was thinking of terminating it in the disconnect. Is it necessary to connect to both disconnects? What have you found to be most acceptable? Oh btw the job is in Coweta county Georgia and in an EMC service area. Thanks.

 

[Dennis Alwon]

If the poco allows you to connect in the meter then, IMO that is the easiest otherwise you will need to connected to both panels. BTW- 2- 200 amp panels is not a parallel install. To be parallel , by definition, the wires needs to be connected together at both ends.

 

[John120/240]

Does your POCO allow the GEC in the meter can ? Some do, others don't. You have two

disconnects located next to the meter. All grounding should happen here at the disconnects.

This makes your indoor panels, sub panels. Therefore four wires are required from disconnect

to panel. Remember to seperate your neutrals and grounds.

 

[super dave]

Dennis you are correct. It is not a parallel connection.

John thanks for the reply. That brings up one more question. What is the best way to run the conductor to both disconnects since it has to be a continuous feed through the two electrodes?

 

[suemarkp]

The GEC only has to be unspliced between the discconnect and the electrode system. Having a multi handle disconnect doesn't mean the CAN must be unspliced between them. Typical ways to ground them:

Run the GEC from a fat neutral (sized per 250.66 for the full 400A conductors) in a common gutter (or in the meter). As long as the neutral to each panel is sized to 250.66 or larger, you're done.
Run the GEC to one of the disconnects, and split bolt on a tail ontl that GEC to hit the other panel. The unspliced GEC may need to be #2 or 1/0, but the tail to the other panel only needs to be #4. I'm not sure why this tail is needed, because in the above approach the neutral to each disconnect is dual purpose grounded and grounding.

Between rods is not required to be unspliced (although some ares may require that). The electrode system is the 2 rods and perhaps a water pipe. Pick some point on that electrode system to attach the GEC and run it per one of the choices above.

 

[infinity]

You can also run one GEC sized according to 250.66 and tap off to each disconnect with a split bolt. GEC taps are not required to be irreversible. Here's a graphic from the NECH:

 

[jumper]

. I plan to install the POCO 400 amp meter base and then connect 2- 200 amp disconnects in parrallel.

To be parallel , by definition, the wires needs to be connected together at both ends.

It's early and I am bored: nit pick time.

While the each feeder/conductor is not using smaller conductors ran in parallel to achieve a greater ampacity per phase/pole and neutral using 310.10(H), the discos themselves are connected in parallel in regard to the meter base.

The meter base is in series to the discos.

 

[hillbilly1]

Does your POCO allow the GEC in the meter can ? Some do, others don't. You have two

disconnects located next to the meter. All grounding should happen here at the disconnects.

This makes your indoor panels, sub panels. Therefore four wires are required from disconnect

to panel. Remember to seperate your neutrals and grounds.

I don't know about all of the EMC'S, but BRMEMC requires the GEC to be terminated in the meter base, where as Georgia Power prohibits it.

 

[kwired]

You can also run one GEC sized according to 250.66 and tap off to each disconnect with a split bolt. GEC taps are not required to be irreversible. Here's a graphic from the NECH:

If I had the installation in that image, I would likely run the GEC to the aux gutter. One thing they did not show in that image is the fact that metal enclosures containing service conductors need to be bonded to the grounded service conductor. If you are making splices or taps to the grounded service conductor in the gutter, why not bring the GEC there also. Make connections on a ground bar that is bolted to the gutter accomplishes both tasks.