EGC conductor sizing in pre fab multi cable.

[Sparky9527]

Hi. I got a question about the EGC sizing in pre fabricated multi conductor cable that project manger ordered from electrical supply. it has 11 circuits all #10 thhn stranded with number 4 thhn EGC. see picture attached. it looks weird for me because the phase conductor only #10, but ground is #4. So I checked 250.122 . my understanding is ground conductor should not larger than phase conductor. we gonna run this multi wire to 1 1/4 emt. all circuits using 20 amp breakers. is the # 4 EGC a violation? any thoughts? thanks

https://imgur.com/a/5AUjUVM

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[kwired]

Didn't check to verify but pretty certain what is mentioned in 250.122 would be that it doesn't need to be larger than 10AWG, but nothing I am aware of would prohibit the EGC from being larger than minimum required.

 

[kwired]

Next question is on the 11 circuits, is there 22 conductors or is there some multiwire circuits involved here (sharing neutrals between ungrounded conductors)? If there is 22 current carrying conductors ampacity adjustment is 45%, making #10 @ 90C only good for 18 amps. If there is MWBC's and the actual number of current carrying conductors is under 20 then your adjustment is 50% and the 10 AWG would be good for 20 amps.

 

[infinity]

A waste of money but code compliant.