How would you size this in the case of a meter-main combo that isn’t using wire to connect the meter to the main disconnect? As in they are bonded through zinc plated aluminum bars.
The GEC is sized based on the SE Conductors that supply the meter combo. From the point of attachment to meter is sized per NEC or if just rods then 6 AWG CU only per 250.66(A).
Also, use note 2 in Table 250.66 if you don't have SE Conductors. You would determine size of conductors needed based on Service installed and use those hypothetical conductors to choose GEC size, unless its Rods, Pipes, Plates, CEE, or Rings per (A)-(C).
@@MasterTheNEC got it, that makes sense! Just thought it was interesting since there’s no SE from meter to main disconnect but looks like they’ve already considered that.
Ok. So from you video of code interpretation, i understood that It is legal to run #6 grounding electrode to 2 ground rods from 1200amp service. So other words: 1,200am service --------》#6wire-------》1st ground rod------》#6wire -------》2nd ground rod. Did I get that right?
When it comes to using 250.66(A) for Ground Rods the ampacity of the system is irrelevant. The allowance in 250.66(A) says the GEC doesn't have to be larger than 6AWG CU or 4 AWG AL.
Chapter 9 , Table 8 has the Circular Mils of the 4/0. So, you would add the two together and then visit Table 250.66 and treat the two 4/0 added together as a single conductor and then select from table. For example, the 4/0 is 211,600 x 2 = 423,200 kcmil. You go to Table 250.66 and use the 423,200 as if it was a single conductor =, which places you in the over 350 through 600 for CU and then side to the right and the GEC would be 1/0 CU or 3/0 AL. Hope this helps. If you are asking WHY we add the 4/0 together, read the header of the first column in Table 250.66. It says " Equivalent Area for Parallel Conductors"....The equivalent area is adding the two conductors circular mil area together.
Did we make a mistake? We are installing a 1200 Amp disconnect, we installed 600 Kcmil wire, but the disconnect only accepts 500 Kcmil wire. Should we had installed 500 Kcmil instead of the 600 Kcmil or the disconnect should accepts the 600 kcmil for 1200 Amps? Brand; ABB Part number; TMAX XT7H1200
Your question lacked details. However, any lug listed for 500 kcmil should not have 600 kcmil installed on it unless the lug is listed to accept 600 kcmil. Since you state the maximum size is 500 kcmil then using 600 kcmil would be a violation of the listing per 110.3(B).
Hi master. Can we use insulated conductor (green) on grounding electrode conductor? I saw a grounding electrode conductor, using white wire, is it okay?
Well, I don't like the idea of "white" being used. However, as a "Code Guy" the white color rules apply to grounded conductors and not GEC's. In fact, the NEC permits the GEC to be insulated, covered, or bare. The 2023 NEC cycle attempted to define the color of insulated bonding jumpers and GEC's and it failed.
If over 1100kcm or 1750 kcm on table 250.66, don't you need to multiply by 12.5 % and then you use chapter 9 table 8 to get correct size of conductor ?
Thanks!
Thanks again for answering my question…fasttrax member
How would you size this in the case of a meter-main combo that isn’t using wire to connect the meter to the main disconnect? As in they are bonded through zinc plated aluminum bars.
The GEC is sized based on the SE Conductors that supply the meter combo. From the point of attachment to meter is sized per NEC or if just rods then 6 AWG CU only per 250.66(A).
Also, use note 2 in Table 250.66 if you don't have SE Conductors. You would determine size of conductors needed based on Service installed and use those hypothetical conductors to choose GEC size, unless its Rods, Pipes, Plates, CEE, or Rings per (A)-(C).
@@MasterTheNEC got it, that makes sense! Just thought it was interesting since there’s no SE from meter to main disconnect but looks like they’ve already considered that.
Ok. So from you video of code interpretation, i understood that It is legal to run #6 grounding electrode to 2 ground rods from 1200amp service.
So other words:
1,200am service --------》#6wire-------》1st ground rod------》#6wire -------》2nd ground rod.
Did I get that right?
When it comes to using 250.66(A) for Ground Rods the ampacity of the system is irrelevant. The allowance in 250.66(A) says the GEC doesn't have to be larger than 6AWG CU or 4 AWG AL.
@@MasterTheNEC Thank you sir
What if you had 4/0 copper parallel how do you add those
Chapter 9 , Table 8 has the Circular Mils of the 4/0. So, you would add the two together and then visit Table 250.66 and treat the two 4/0 added together as a single conductor and then select from table. For example, the 4/0 is 211,600 x 2 = 423,200 kcmil. You go to Table 250.66 and use the 423,200 as if it was a single conductor =, which places you in the over 350 through 600 for CU and then side to the right and the GEC would be 1/0 CU or 3/0 AL. Hope this helps. If you are asking WHY we add the 4/0 together, read the header of the first column in Table 250.66. It says " Equivalent Area for Parallel Conductors"....The equivalent area is adding the two conductors circular mil area together.
Did we make a mistake? We are installing a 1200 Amp disconnect, we installed 600 Kcmil wire, but the disconnect only accepts 500 Kcmil wire.
Should we had installed 500 Kcmil instead of the 600 Kcmil or the disconnect should accepts the 600 kcmil for 1200 Amps?
Brand; ABB
Part number; TMAX XT7H1200
Your question lacked details. However, any lug listed for 500 kcmil should not have 600 kcmil installed on it unless the lug is listed to accept 600 kcmil. Since you state the maximum size is 500 kcmil then using 600 kcmil would be a violation of the listing per 110.3(B).
Hi master. Can we use insulated conductor (green) on grounding electrode conductor? I saw a grounding electrode conductor, using white wire, is it okay?
Well, I don't like the idea of "white" being used. However, as a "Code Guy" the white color rules apply to grounded conductors and not GEC's. In fact, the NEC permits the GEC to be insulated, covered, or bare. The 2023 NEC cycle attempted to define the color of insulated bonding jumpers and GEC's and it failed.
Thanks master. I appreciated it.
If over 1100kcm or 1750 kcm on table 250.66, don't you need to multiply by 12.5 % and then you use chapter 9 table 8 to get correct size of conductor ?
Nope....I think you are confusing 250.66 with 250.102(C)(1) or your using an NEC from before 2005 maybe.