Confused about GEC requirement when there is only UFER available

[donw]

Now days with most water piping being entirely PEX (even the supply at the street), in a wood framed building there may only be grounding to the UFER. So do we only need to size the service ground wire #4 CU even if the service is 1000A, for example?
This example below has me a little confused, because it says the jumper from the busbar to the UFER is a GEC and needs to be sized per 250.66 using the sum of the circular mil of the largest ungrounded conductors. I would have thought the connection from the busbar to the UFER would only be required to be #4 CU per 250.66(B). So it got me thinking about cases where there only a UFER and no water or metal to bond to.

 

[tom baker]

Please see the rest of section 250.66 for sizing GEC to ground rods, ufers, and rings

 

[infinity]

The GEC need not be larger than #4. The taps can be smaller to each service disconnect based on the service conductors to each disconnect and T250.66.

 

[donw]

Please see the rest of section 250.66 for sizing GEC to ground rods, ufers, and rings

I did, but none of those require you to use the sum of the circular mil area of the largest ungrounded conductor.

 

[don_resqcapt19]

I did, but none of those require you to use the sum of the circular mil area of the largest ungrounded conductor.

Because for (A) and (B) the sum of the area of the service conductors does not matter. The 6 AWG for (A) and the 4 (AWG) for (B) are the largest GECs that are required no matter what the total circular mil area of the ungrounded service conductors may be.

Note that many engineers will require a GEC much larger than the minimum permitted by the code.

 

[Jaybone812]

The GEC need not be larger than #4. The taps can be smaller to each service disconnect based on the service conductors to each disconnect and T250.66.

This is another topic of complete confusion for the ones responsible for submitting PI for 625.54 gfci protection of all evse on the other thread . They insist that 250.66(a) and (B) are saying the gec that connects to a CEE must be a #4 cu conductor no matter what , and the gec that connects to a rod must be a #6 cu conductor no matter what , regardless if table 250.66 permits the use of a smaller conductor and it’s a violation to use a larger conductor as well lol.

 

[infinity]

They insist that 250.66(a) and (B) are saying the gec that connects to a CEE must be a #4 cu conductor no matter what

That is incorrect. #4 is the maximum size required. Table 250.66 also lists GEC sizes of #8 and #6 which are both permitted to be connected to the CEE. Same with a ground rod a #8 is permitted as the GEC.

 

[Jaybone812]

That is incorrect. #4 is the maximum size required. Table 250.66 also lists GEC sizes of #8 and #6 which are both permitted to be connected to the CEE. Same with a ground rod a #8 is permitted as the GEC.

Most definitely. Their thought process is so flawed. We all know it’s completely incorrect but they will insist they are the only ones that have the code correct interpretation, but there’s nothing left up to interpretation in 250.66(a)-(b) lol

 

[infinity]

Most definitely. Their thought process is so flawed. We all know it’s completely incorrect but they will insist they are the only ones that have the code correct interpretation, but there’s nothing left up to interpretation in 250.66(a)-(b) lol

I have heard that same thing about the #6 and #4. People need to really peruse the code not just skim over it.

 

[Jaybone812]

I have heard that same thing about the #6 and #4. People need to really peruse the code not just skim over it.

And they try to substantiate the claim in reference to rhe gec to CEE connection by saying a # 4 cu conductor’s sole connection to a CEE by way of exothermic weld , is the only size conductor that’s ever been tested making that type of connection and any other conductor has not been tested so there could be air gaps when the connection is made via exothermic weld , I said what about when a piece of rebar is stubbed through the foundation and is used to extend the connection to the actual CEE and you make the gec to CEE connection with a listed clamp , how do possible exothermic weld connection failures affect the connection when it’s made by a clamp lol, not that there would be a failure if the cad weld is done correctly

 

[infinity]

And they try to substantiate the claim in reference to rhe gec to CEE connection by saying a # 4 cu conductor’s sole connection to a CEE by way of exothermic weld , is the only size conductor that’s ever been tested making that type of connection and any other conductor has not been tested so there could be air gaps when the connection is made via exothermic weld , I said what about when a piece of rebar is stubbed through the foundation and is used to extend the connection to the actual CEE and you make the gec to CEE connection with a listed clamp , how do possible exothermic weld connection failures affect the connection when it’s made by a clamp lol, not that there would be a failure if the cad weld is done correctly

Yup, as with a lot of this stuff misinformation is everywhere. Look no further than YouTube if you really want to get things wrong. I try to avoid anything electrical on YouTube but on occasion I may click on something in my feed and I estimate that more than 50% of the time what's depicted in the video is wrong.

 

[Jaybone812]

Yup, as with a lot of this stuff misinformation is everywhere. Look no further than YouTube if you really want to get things wrong. I try to avoid anything electrical on YouTube but on occasion I may click on something in my feed and I estimate that more than 50% of the time what's depicted in the video is wrong.

Definitely man. Only industry related material I’ll even acknowledge on YouTube is Ryan’s channel . Other than that, most of it is opinion based misinformation like you said

 

[don_resqcapt19]

And they try to substantiate the claim in reference to rhe gec to CEE connection by saying a # 4 cu conductor’s sole connection to a CEE by way of exothermic weld , is the only size conductor that’s ever been tested making that type of connection and any other conductor has not been tested so there could be air gaps when the connection is made via exothermic weld , I said what about when a piece of rebar is stubbed through the foundation and is used to extend the connection to the actual CEE and you make the gec to CEE connection with a listed clamp , how do possible exothermic weld connection failures affect the connection when it’s made by a clamp lol, not that there would be a failure if the cad weld is done correctly

CadWeld has listed molds for connecting conductors as small as 10 AWG to rebar. If the mold is listed, it has been tested for the specified combination of conductor and rebar size.

 

[Jaybone812]

CadWeld has listed molds for connecting conductors as small as 10 AWG to rebar. If the mold is listed, it has been tested for the specified combination of conductor and rebar size.

As to which I’m very aware which is what makes his thought process even more flawed . The code says what it says and the language is very clear on this in my opinion issues that he feels what he feels could present themselves are irrelevant and if he is so confident on this matter why wasn’t that brought to the committee as well ? They submitted a pi to revise codes in a way that will support every other piece of misinformation they like to spread why not for that this as well ?lol

 

[donw]

Because for (A) and (B) the sum of the area of the service conductors does not matter. The 6 AWG for (A) and the 4 (AWG) for (B) are the largest GECs that are required no matter what the total circular mil area of the ungrounded service conductors may be.

Note that many engineers will require a GEC much larger than the minimum permitted by the code.

So doesn't that make the graphic incorrect?

 

[infinity]

So doesn't that make the graphic incorrect?

What makes you think that it's incorrect? It doesn't have any wire sizes in the graphic and it does tell you the correct way to calculate the size of the GEC. If instead of the CEE what if there were a water pipe electrode how would you size the GEC?

 

[Jaybone812]

So doesn't that make the graphic incorrect?

No because the graphic says the taps to each enclosure are based off the size of the largest ungrounded conductors at that enclosure. It would be incorrect if it said the size of the taps to each enclosure are based off the sized of largest ungrounded service conductors