Service Entrance Grounding Wire Sise

Status
Not open for further replies.
S

SteveHayden

Member
Location
Fort Myers, FL US
We are upgrading a 200 AMP service to a 400 AMP. My understanding from the code is this would require a #4 bare copper wire for grounding if the new service entrance disconnect. Just looking for confirmation.


Sent from my iPhone using Tapatalk
 
I assume you mean the grounding electrode conductor? If so that would depend on how your service is install. For instance, if you have 2- 200 amp service panels then you could run 2- runs of #4 to the grounding electrode- water pipe???... or you could run a #2.

If you use a meter main combo bo then you need a 1/0 grounding electrode conductor.
 
SteveHayden said:
We are upgrading a 200 AMP service to a 400 AMP. My understanding from the code is this would require a #4 bare copper wire for grounding if the new service entrance disconnect. Just looking for confirmation.
Click to expand...

There are many varying factors. What do you mean by "grounding"? If you're referring to the grounding electrode conductor (GEC) as Dennis mentioned then you would need to mention the type of electrode you're using. A ground rod requires #6, a CEE #4 and a water pipe a #1/0 or #2.

Welcome to the Forum. :)
 
SteveHayden said:
Not a meter main combo. 400 amp meter feeding two 200 amp panels. The main ground off of the meter I believe just needs to be #4 bare copper.


Sent from my iPhone using Tapatalk
Click to expand...


No-- It needs to be #2 but it depends on the service conductor wire size. #4 is good for 200 amp not 400 amp. The wire to the ground rods only needs to be #6
 
SteveHayden said:
Not a meter main combo. 400 amp meter feeding two 200 amp panels. The main ground off of the meter I believe just needs to be #4 bare copper.
Click to expand...
What type of electrode is it connecting to? How many different types of electrodes are present?

Roger
 
It is sized per the incoming ungrounded conductor. You said you have a 400 amp meter and 2-200 amp panels. That incoming conductor does not necessarily need to be a 400 amp conductor - with multiple disconnecting means it can be sized per calculated load. Or if you had a long run and increased size for voltage drop it very well may be large enough you need more than #2 GEC. Bottom line is 400 amps doesn't mean a lot for sizing this conductor, it only tells us what might be typical.
 
SteveHayden said:
We are upgrading a 200 AMP service to a 400 AMP. My understanding from the code is this would require a #4 bare copper wire for grounding if the new service entrance disconnect. Just looking for confirmation.


Sent from my iPhone using Tapatalk
Click to expand...
Greetings,

Many numbers being thrown out in this thread but I feel you have asked a question with many open-ended assumptions.

(1) What Grounding Electrode do you have on your Grounding Electrode System?
(2) What are the "actual" sizes of the conductors you are installed versus just giving ampacity values, always hate to assume others know how to "size" conductors for a specific value specified.

As others have said, if your existing GES was comprised of "Ground Rod(s)" then 6 AWG CU would be all that is needed. However, I elect to not assume anything since 4 AWG CU is also the minimum required size for a CEC "Concrete Encased Electrode" as well so again without specifics you get general responses.
 
This reminds me of a similar question I used to use in my classes
"What size ground for a 200 Ampere service"

Which can't be answered with the information given.
The definition of ground is "Ground. The earth."

I think I know what the OP is asking about ("what color is it and what does it do"- Mike Holt)

To the OP, if you would ask using code terms then its a simple process to answer your question.
Grounding does not have to be confusing, "we have met the enemy and he is us" Pogo
 
Status
Not open for further replies.
Top