Replies

1. 
   JTC1 | Dec 22, 2009 05:14pm | #1

   >>-In the new Sub Panel, the neutral bonding screw is left out . Grounds go in the ground bar, neutrals in the neutral bar. Correct?<< Correct. >>-In the main service panel in the house the bonding screw is inserted. The neutrals & grounds are mixed in both bars, but since everything is common this is OK?? For instance, on any given circuit the neutral & ground may land on the same terminal in the bar.<< Correct again. >>-And both of these bars are full. I bought an additional grounding bar & the sales person assured me there were tapped holes in the box to fasten the bar. Not true. So I need to tap the box to fasten the bar & remove paint to ensure proper contact?<< The two bars referenced are in the MAIN SEP - not a sub-panel? If yes, you do not need an additional ground bar. >>-The house originally had a 100A Service. When I enlarged the house & installed a 200A Service we turned the original service into a 100A Sub Panel. There is one bar in this older panel that has both neutrals & grounds & is bonded to the box. So I guess that bonding strap should be removed?<< Correct again. >> And must I insert a bar..<< not neceassarily, if there is space on the existing bars - you do not need to add any additional bars >>... & separate the grounds & neutrals?<< Correct again. Is the "new" shop sub-panel in the same building as the main SEP? If no, and it is in a separate building, you will need to add ground rods at that separate building. Jim

1. 
   Paladin51 | Dec 22, 2009 05:29pm | #2

   Thank You Sir.

   Further...

   -On the main SEP panel both bars are completely full, there isn't room to connect my neutral & ground from the Sub-Panel.

   -In the old, former SEP, now a Sub Panel, there is only 1 bar, so both grounds & neutral are on the same bar.

   Thanks

1. 
   JTC1 | Dec 22, 2009 05:42pm | #3

   >>-On the main SEP panel both bars are completely full, there isn't room to connect my neutral & ground from the Sub-Panel.<>-In the old, former SEP, now a Sub Panel, there is only 1 bar, so both grounds & neutral are on the same bar.<<

   I assume (always dangerous) that this one bar will "float" electrically with the bonding screw / strap removed? If yes, then this will become your neutral bar and a new ground bar will have to be added. If the box has no holes for a ground bar - you will need to bore and tap new ones. Is the ground bar you bought from the same maufacturer as the panel enclosure? If yes, there should be pre-bored holes for it. If no, it becomes anybody's guess - bore and tap.

   Jim

1. 
   Paladin51 | Dec 22, 2009 08:41pm | #4

   Thank You Again.

   And yes the SubPanel will be in the shop, not in the house. I haved driven a ground rod in the soil beside the building. You mention ground rod"s". I believe I have read somewhere also that & I need 2 rods 2' apart?

   Why?

   Thanks JDH

1. 
   JTC1 | Dec 22, 2009 11:01pm | #5

   2 rods, 10'(or more) apart
   2 rods, 10'(or more) apart will do nicely; 2' between rods = way too close together.

   Continuous run of #6 or #4 solid, bare, copper wire clamped to rods with a "similar metal", "direct burial" rated clamps (will have "DB" cast right into the clamp).

   Copper or copper clad rods need bronze clamps.

   Wire run = ground bar in sub panel -> rod #1 -> rod #2.

   No splices - one piece of wire.

   Bury the wire run by 6" or so - I like to dig the wire in right next to the foundation and try to place the rods in the "drip line" of the roof edge - damper soil = better grounding.

   Ground rods provide some lightening protection. Two rods are used to avoid a resistance test which virtually no one has the instrumentation to perform properly. Two rods and you are covered without testing.

   Jim

2. 
   jimjimjim | Dec 22, 2009 11:26pm | #6

   >> >>-In the main service panel in the house the bonding screw is inserted. The neutrals & grounds are mixed in both bars, but since everything is common this is OK?? For instance, on any given circuit the neutral & ground may land on the same terminal in the bar.<< Correct again. <<

   Depends on the panel - some manufacturers specify only 1 neutral connection per terminal screw. (But in the main panel grounds and neutrals can share the same bar).

   Jim x 3

1. 
   Paladin51 | Dec 22, 2009 11:33pm | #7

   Thank You

2. 
   BillHartmann | Dec 23, 2009 09:27am | #8

   The neutrals & grounds are mixed in both bars, but since everything is common this is OK?? For instance, on any given circuit the neutral & ground may land on the same terminal in the bar.

   At the service entrance, which is the first disconnect past the meter, usually the main pannel, the grounds and neutrals are bonded together.

   And some electricians will mix ground and neutrals on the closes bus. Other will keep them separate. Either is right.

   But at any sub-panels they are isolated.

   But I have found many older installations where that was not donel. Or in cases like yours where the main later became a sub that someone did not bother separate them.

   Note - that also means that there needs to be a 4 wire feed to the sub, 2 hots, neutral, and ground.

   For instance, on any given circuit the neutral & ground may land on the same terminal in the bar.

   Not exactly true.

   Many panels are speced to have 2 or more wires in one whole. That will show on the label.

   And the code has long said that there can only be one Neutral in a hole. And by this a ground and neutral where often put in the same hole. But apparently the intent was that the neutral should not have ANYOTHER wires in that hole. So newer versions of the code has been changed to make that clear.

   So you can have multiple grounds in one hole, as speced on the label, but a hole with a neutral can't have anything else in it.

   I would not bother to change existing ones.

1. 
   Paladin51 | Dec 23, 2009 02:36pm | #9

   Thank You Sir

2. 
   Paladin51 | Dec 23, 2009 11:31pm | #10

   The one neutral/hole rule creates a dilemma. I have a 40 space panel which provides the possibility of landing 80 wires, 40 neutrals & 40 grounds.(I realize that with 220v circuits I don't need to land a neutral) Add the fact that #4 ground & #2 neutral for the sub panel occupy multiple holes.

   The panel manufacturer did not provide near that many locations. Myself & someone before me have doubled & even tripled up on the neutrals/per hole. Appears that should be corrected.

   So, my course of action is to drill & tap the back of the panel, scrape paint off to ensure good contact & mount another bar?

   Interestingly, the sub panel (GE) provides more than enough locations, 12 breaker spaces with 3 bars!

   Thanks, JDH