star grounding question...


I'm not sure that I understand this concept. What is star grounding? How is it done? Should my dedicated A/C sub panel be star grounded? What are the advantages? And is there any danger?---(lightning strikes, other problems...) Thanks!
talon4
BTW Elgordo, being gravitationally challenged himself, has no business poking fun at Star Jones. Sorry. Just couldn't resist.
So how does star grounding apply to an A/C sub panel? What my electrician did is run a 40 amp 65' 8 gauge non-armored A/C cable from the main A/C panel to the sub panel. I then have 4 20 amp 7' runs of 10/2 romex to my A/C sockets. The only ground rod that I have is a 10' 5/8" commercial grade ground rod that goes to my main A/C panel. Should I have a separate ground rod for the sub panel or a separate ground wire from the sub panel to the main panel or some other configuration? The system sounds great, but maybe there's something that I can do to get a lower noise floor. I plan on using cryoed breakers and already have good A/C sockets. I also plan on using Virtual Dynamics A/C wire to replace the 8 and 10 gauge wire that I have presently. Thanks! Stan
Talon4
65' #8 awg wire, that's kinda small wire for the distance. I am just guessing but the electrician installed 8-3 with/ground nmc, romex, for your sub panel feed. 2 hots, 1 neutral, and bare ground. The bare ground is terminated on the neutral/ground bar in your main electrical panel, just where it should be. Your sub panel is 120/240 volt, 40 amp rating.
Star grounding, "Nsgarch" said it well.
Inside your sub panel there is a separate bar for grounding. This ground bar is where the electrician connected the bare grd wire from the #8-3 w/grd feeder. This grd bar is also were the branch circuit equipment grds connect to. A common ground point, star ground.
No separate ground rod for a sub panel.

Jim
Jea48-Yes, that sounds accurate. I watched the whole process. Also, my electrician said that 8 gauge was okay up to 180', after that 6 gauge is the way to go. So are you saying that it is already star grounded? Any ideas are welcome. Thanks! Stan