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#51018 04/19/05 09:25 PM
Joined: Mar 2002
Posts: 179
D
derater Offline OP
Member
Marc; yes it's a rental-guy has a motorcycle shop in it.No metal path between
the blgs. NOW,but if the bike guy gets a hardwired phone.....I want to be able to justify the idea of running a ground and /or gnd, rod.

#51019 04/19/05 09:43 PM
Joined: Feb 2003
Posts: 939
F
Member
Ok Derater then it is better off to run 4 wires and add ground rods there because you never know if they will add water line or phone line so this is a good and safe way to do this

Merci, Marc


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

#51020 04/19/05 10:34 PM
Joined: Oct 2004
Posts: 135
B
Member
Derater, if it is already wired and you're just making sure it is safe there are a few things I would check. Are the neutrals and grounds bonded in the sub-panel? With a 3 wire feeder this sub should be treated as a service and the neutral and ground buses should be bonded together. If it is a 4 wire feeder, of course they should be separate. Is there a grounding electrode system, there should be. If you only have a 3 wire feeder and you isolate the grounds and neutrals you will have no ground fault protection. Any ground fault current will go straight to earth (if there's an electrode) and probably will not clear the fault, essentially leaving whatever device or load that caused the fault energized and posing an hazard. 2002 nec permits this installation, see 250.32 B2. Check it before you insist on a 4 wire feeder, this installation can be made safe. Make sure you bond the building steel.

[This message has been edited by BobH (edited 04-19-2005).]

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