GROUNDING CONDUCTOR SIZE

[ohmhead]

Well the latest code requirement tell us to increase the ground size when we change for any reason the phase/neutral sizes for VD.
Question smaller wire like 10 Awg if you increased to a 8 Awg it would be a 8 Awg increase. Now say i had a feeder increase to a 500 mcm for VD the ground size increases to a 500 mcm or would it increase to the ratio of the increase percentage of the VD conductor sizes.

Meaning the difference between the two sizes of phase conductors ?

Divide one into the other ? use that number to increase the original ground in that raceway and it could be less than 500 mcm ?

If paralleled conductors are used would this be for each raceway or would the size be for total ampacity

Next question why are they doing this please explain in detail .

 

[jumper]

Well the latest code requirement tell us to increase the ground size when we change for any reason the phase/neutral sizes for VD.
Question smaller wire like 10 Awg if you increased to a 8 Awg it would be a 8 Awg increase. Now say i had a feeder increase to a 500 mcm for VD the ground size increases to a 500 mcm or would it increase to the ratio of the increase percentage of the VD conductor sizes.

Meaning the difference between the two sizes of phase conductors ?

Divide one into the other ? use that number to increase the original ground in that raceway and it could be less than 500 mcm ?

If paralleled conductors are used would this be for each raceway or would the size be for total ampacity

Next question why are they doing this please explain in detail .

It has been a rule for awhile.

It is the proportional ratio.

Yes you gotta increase it for for each raceway.

I leave the explanation to someone else.

 

[jumper]

Here is a bunch of threads on the subject.

https://www.google.com/search?q=250...or.r_gc.r_pw.r_qf.,cf.osb&fp=658b538c23bb4e18

 

[infinity]

250.122(B) only applies to phase conductors not the neutral.

 

[roger]

Next question why are they doing this please explain in detail.

Simple, the EGC's impedance increases with length which hinders it's ability to clear a fault.
With that said, the article section requirement (as far as the NEC's across the board wording) needs to be worked on for smaller sized circuits.

Roger