Replies

1. 
   caseyr | Dec 30, 2003 07:59am | #1

   See if these help:

   http://www.homepower.com/files/codecorner73-76.pdf?search=grounding

   and possibly in the Feb/Mar and April/May sections of:

   http://www.homepower.com/files/codecorner60-72.pdf?search=grounding

   (At least that should keep you entertained until someone here actually answers your question...)

1. 
   lyledesign | Dec 30, 2003 09:04pm | #7

   Thanks for your reply.  One of the articles adresses exactly this issue, and I went to bed last night with the feeling that the proglem was solved.  Unfortunately (perhaps predictably), the subsequent pieces of advice that folks have been kind enough to give me have all contradicted this first theory--so far 1 for each of the options that I offered!  Thanks again, I think I'll go with the HP suggestion you forwarded.

2. 
   marv | Dec 30, 2003 04:43pm | #2

   Run three wires and ground to new box. (two hot and one neutral and one ground)  In the house sub panel the ground is connected to the ground buss and the neutral is connected to the neutral bar.  remove the jumper between the two so that they are independent.  Hots feed the panel.

   You get out of life what you put into it......minus taxes.

   Marv

1. 
   BillHartmann | Dec 30, 2003 04:48pm | #3

   You still need a ground electrode (ground rod or other) at the house.

1. 
   booch | Dec 30, 2003 05:18pm | #4

   Great answers, all correct as far as I know. Further clarification please at the main. Do you need both the ground rod pair on the exterior of the structure at the main feed as well as a ground rod in the interior of the house main feed. (I'm ignoring the subpanel here)Jack of all trades and master of none - you got a problem with that?

1. 
   BillHartmann | Dec 30, 2003 07:44pm | #5

   "Do you need both the ground rod pair on the exterior of the structure at the main feed as well as a ground rod in the interior of the house main feed."

   I am not sure what you mean. But let me go over the rules. They are fairly detailed so I don't be surprised if someone finds a mistake in this.

   You have the Grounding Electrode System which can be ground rods and/or other options. And the Grodunding Electrode conductor which is an unspliced wire that goes from electrode(s) to ONE and ONLY ONE point in the wiring system and that is at the main disconnect, which is typically the main pannel.

   Primary electrodes can be a metal underground water pipe in contact with the earth for at least 10ft, the metal frame of building where effectively grounded (whatever that means), concrete-encased electrode (Ufer ground - 20 ft of wire or steel rebar in concrete footings) or a ground ring (buried wire encircling the building). The underground water pipe requires a suplimental electtrode where the others don not any extra electrodes.

   You can also use Made Electrodes. Those are pipes, rods and plates. If you only use made electrodes and it does not test out to less than 25 ohms then a 2nd made electrode is required and it has to be at 6ft away.

   Now a method common in many house is to use the metal water pipe with a secondary ground rod.

   But you could also use the Ufer ground in the footings as the only ground electrocde.

   But even if you do that you will still need to bond the water pipe and the gas pipe, etc.

   A gas pipe has to be bonded, but can never be used as the ground electrocde. For a water pipe I think that it takes a Philidelphia lawyer to tell the difference.

2. 
   lyledesign | Dec 30, 2003 08:58pm | #6

   Marv,  thanks for your reply.  I'm not clear however why I should run 2 hot wires.  All I am dealing with here is 120v. 

1. 
   marv | Dec 30, 2003 10:14pm | #8

    why I should run 2 hot wires.

   You need two hot wires for balance.  When power comes in from the street, you have two wires and two phases.  When you load the circuits you try to balance out the current draw between the two wires.  It may be different if you're dealing with batteries, I'm not sure on that.You get out of life what you put into it......minus taxes.

   Marv

2. 
   BillHartmann | Dec 31, 2003 03:25am | #9

   If you aren't planning on either connecting to commerical power and your inverter only puts out 120 then can't use the 2nd hot.

   But most system use 240/120 supplies, even if all of the loads are 120, and require 2 hots and a neutral.