Erby Posted February 11, 2009 Report Posted February 11, 2009 So help me I'll never fully understand Grounding and Bonding. There's a meter box at the exterior right back of the house. A Grounding Conductor runs from the meter into the ground, presumably to the ground rod. The service is underground. Click to Enlarge 41.52 KB Three wires run from the meter to the exterior Service Disconnect (located a foot or so to the right of the meter box) thru plastic conduit. Click to Enlarge 56.77 KB Four wires run to the distribution panel on the back wall of the garage. Click to Enlarge 69.19 KB Copper wire runs from the Service Disconnect Equipment Ground to the copper pipes above the water heater. Click to Enlarge 60.4 KB The Service Disconnect Panel Diagram. Click to Enlarge 65.13 KB Why is there no need to connect the ground rod to the Service Disconnect Equipment Ground? -
Jim Katen Posted February 11, 2009 Report Posted February 11, 2009 . . . Why is there no need to connect the ground rod to the Service Disconnect Equipment Ground? There is a need to connect them. In your pictures, they're connected via the green bonding screw next to the neutral terminal lugs. - Jim Katen, Oregon
Erby Posted February 11, 2009 Author Report Posted February 11, 2009 Ah, just the person I'd hoped for. So, you're saying they ARE already connected because the neutral carries the ground between the meter base and the service disconnect?
charlieb Posted February 12, 2009 Report Posted February 12, 2009 Ah, just the person I'd hoped for. So, you're saying they ARE already connected because the neutral carries the ground between the meter base and the service disconnect? I'm sure Jim will correct this if I'm wrong...............yes. The correct name for for the neutral is The Grounded Conductor.
Richard Moore Posted February 12, 2009 Report Posted February 12, 2009 Erby, I'm a little confused here. I see the SE-Cable exiting the service panel along with a separate copper grounding conductor into PVC conduit (pics 2 & 4). At the distribution panel (pic 3) I see only the SE-Cable entering (and it looks like a metal bushing there). Where does the copper GEC, the one connected to the pipes, split off? You say there is a GEC from the meter to, presumably, ground rods and another to the copper pipes. Are you sure the first is actually coming from the meter base and not from another "box" where the two GECs might be connected? Could it actually be a UFER ground and the connection made behind a wall plate in the garage? That make any sense?
Erby Posted February 12, 2009 Author Report Posted February 12, 2009 Richard, It's not two sides of the same wall. Wires travel from the Service Disconnect to the distribution panel thru the attic over the bedrooms (not in conduit).
Richard Moore Posted February 12, 2009 Report Posted February 12, 2009 Ahhh! Thanks. That splains that. You guys do do things a little different back there. [:-bigeyes What the hell you doing up at this time? I'm just finishing off a report and about to go to bed. You get up at 5:30 am?
Jim Katen Posted February 12, 2009 Report Posted February 12, 2009 Ah, just the person I'd hoped for. So, you're saying they ARE already connected because the neutral carries the ground between the meter base and the service disconnect? Yes. The grounding electrode conductor can connect to the neutral at the service disconnect or before it. (250.24(A)(1)) If I understand your situation correctly, you've got a grounding electrode conductor going from a ground rod to the meter can. Then you have another grounding electrode conductor from the metal water piping (and possibly to a Ufer as well) to the service disconnect panel. They're both connected to the neutral at the service disconnect or before it, so I don't see a problem. As far as I can tell, there's no rule that says multiple grounding electrode conductors have to terminate at the same spot. The equipment grounding conductor has to be bonded to the neutral and to the grounding electrode conductor. (250.130(A)) Your equipment grounding conductor is bonded to the water-pipe grounding electrode conductor by sharing a lug with it and it's connected to the ground-rod grounding electrode conductor via the green screw and the service neutral. Is that more confusing, or less? I think that the contents of Article 250 would be a whole lot easier to understand if they stopped using the term "ground" to mean so many different things. They need to overhaul their terminology. - Jim Katen, Oregon
hendrix Posted February 12, 2009 Report Posted February 12, 2009 Grounding is a connection to the earth. Bonding is the connection of things to each other.[:-banghea
Erby Posted February 13, 2009 Author Report Posted February 13, 2009 Richard: Yup! Jim: Less. Thank you for the help.
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