600A Service grounding

[frogneck77]

I am pricing a service reconfiguration in a strip mall. The existing service is 600A into a CT cabinet with MCB, then is distributed out from there. The space is being subdivided, so they hired an engineer to reconf the service. The engineers' drawing has the service lateral (parallel 350's)entering into a 12x12 trough, then tapping off to (3) 200A meters and disconnects. My question concerns grounding- Whats the easist/most cost effective way to ground the system. The drawing has no info regarding this, and I dont have much experience grounding systems of this type,i.e.-With no Main breaker or switchgear. Any suggestions would be appreciated
Bill

 

[RUWired]

Any suggestions would be appreciated
Bill

Bill, I would think that running a GEC based on the parallel 350's and tapping off that to the seperate 200 amp disconnects with a GEC based on the size of the tap conductors to the meter bases.
Rick

 

[frogneck77]

That sounds like a good suggestion. I was thinking it would be difficult to loop a 2/0 CU from disco to disco unbroken-Which is how Ive done every multifamily service Ive ever done.

 

[frogneck77]

What about 250.64(c)- I dont have an exothermic welder- any links to irreversible compression type connectors?

 

[frogneck77]

Nevermind- I looked down and read the section on GEC taps- I know how it needs to be done now-Thanks for the reply

 

[stickboy1375]

Pretty good example of your scenario...

View attachment 1492

 

[jerm]

I dont have an exothermic welder-

exothermic welding doesn't require any type of "welder". You just need the right molds and the stuff to put in them. Fun stuff, kind of hard to get right on the first try imho.

http://www.erico.com/products.asp?folderid=138

 

[electricalperson]

exothermic welding doesn't require any type of "welder". You just need the right molds and the stuff to put in them. Fun stuff, kind of hard to get right on the first try imho.

http://www.erico.com/products.asp?folderid=138

my favorite part of the trade :grin:

 

[frogneck77]

Cool stuff-What does one of those setups run? I am always interested in new products to make jobs easier

 

[jerm]

The metal (that you use up) only runs a buck or two per shot. I don't remember how much the molds are. They have an electric lighter now that looks pretty cool, we never used one of those before. just flint.

http://www.nettechdi.com/caddyweld_video.htm

 

[infinity]

I wouldn't worry to much about Cadwelding in this setup. Just run your GEC sized as RUWired said and tap off to each disco with a split bolt.

 

[tryinghard]

The engineers' drawing has the service lateral (parallel 350's)entering into a 12x12 trough, then tapping off to (3) 200A meters and disconnects. My question concerns grounding- Whats the easist/most cost effective way to ground the system.

Usually the parallel 350's land in a bus gutter, if so your GEC can terminate in the bus gutter with the neutral and not at each service disconnect. Sounds like you have one service entrance that is parallel, 250-24(A).

If you can access earth (even drill the floor) drive a rod-or two then run a #6 cu, 250-(A)(5) & 250-66(A).