What Size Ground Wire for Sub-Panel

[porschedude996TT]

Hello,

I am about to pull wire for my new shop build from an existing house main panel. The sub-panel is 100amp/240v and I am running 3AWG for the two lines and the neutral. This is running in 1-1/4 plastic conduit and is about a 60 foot run. I bought enought 3AWG for the four conductors, but want some advice in case the pull effort is too hard. I believe that I can reduce the wire size on the ground wire, but how small can I go? And can it be a bare wire?

 

[rinny_tin_tin]

Hello,

I am about to pull wire for my new shop build from an existing house main panel. The sub-panel is 100amp/240v and I am running 3AWG for the two lines and the neutral. This is running in 1-1/4 plastic conduit and is about a 60 foot run. I bought enought 3AWG for the four conductors, but want some advice in case the pull effort is too hard. I believe that I can reduce the wire size on the ground wire, but how small can I go? And can it be a bare wire?

Gnding conductor size is determined by your current carrying conductors - in this case - you say 3 AWG. According to 2002 NEC Table 250.66 your gnding conductor can be 8 cu or 6 Al

 

[rinny_tin_tin]

...another item to consider - get cable pull lube - like as made by Ideal or equal and use plenty of it before and during pull. If you don't have too many bends, you get the pull line connected just right, you should be able to get your 3 AWGs and No. 6 bare cu. through 1-1/4 conduit. Use bare gnding wire

 

[wakeboarder311]

you need to use nec 250.122 because its an equipment ground and not a service ground. so its a number 8 copper ground