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| Subject - Grounding at Breaker Box | |
| glendatgw |
In the breaker panel, can the ground and the neutral share the same buss bar? |
| Mitch | quote: Only if the breaker panel also serves as the service disconnect. If this panel is fed from a main disconnect or another panel then the answer is no. |
| Scott Vickrey | Good answer Mitch. |
| glendatgw | quote:thank you |
| vern | Question on bonding, what would the result be if both main disconect and sub panel were bonded in their panels? How would it affect ground fault protection? |
| JimmyDee | I would like to welcome you to the forum. There is a lot of electrical knowledge here. Most questions will be answered in a timely fashion and don't hesitate to contribute you knowledge. I don't think it would effect the GFCI at all. This would not be legal however. Jim |
| Ed MacLaren | quote: Some of the unbalanced load current would flow on the equipment bonding (grounding) conductor. A service GFP sensor (if installed) would interpret that as a ground fault. Ed 
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| cs409 | good post by all. the confustion comes from the thoughts that electric power can flow up hill, down hill, left, right, forward, backwards and so on. sense the bonding,grounding,neutral or all together in the main service we/they tend to think, whats the problem when you go to another panel! its a problem thats been around for years and will confuse the best in years to come. what we seem to forget that when we run power to another panel, that we have either 1 or 2 ungrounded conductors, and 1 ground(or neutral) conductor, and 1 bonding/equipment grounded conductor(aka, bare/green wire).... as in the diagram above, you need to make sure the neutral and the equipment grounding conductor r not bonded in the 2nd panel, or u end up making the equipment grounding conductor a current carring conductor in parallel with the neutral! Ed MacLaren , could you share your source on the diagram you posted? if not, if you could post some more diagrams it would be nice,,,,thanks. |
| JimmyDee | Ed, that diagram clears up that question. It clearly shows a parallel path for neutral current. This will definitely screw up the ground path used by the GFCI. I think the GFCI will still work but certainly not to the safety specifications that are necessary for protection of life or reliability from nuisance trips. Thanks for a great visual explanation. Jim |
| Ed MacLaren | quote: The diagram is one that I produced for an apprentice training seminar. The diagram doesn't represent a GFCI, it illustrates a typical service ground fault protection system, which is what I thought Vern was asking about. It is designed to limit damage to conductors and equipment, not to protect people from electrocution. Typical trip settings could be between 100 and 1200 amps, whereas a GFCI is set to trip at 4 to 6 milliamps. A branch circuit GFCI will definitely trip if the neutral is bonded to ground on the load side of the GFCI. Ed |
| JimmyDee | OK we are talking apples and oranges. Looking at the diagram, I can see the ground fault breaker set up. I can also see that there is an additional path for either neutral current or ground fault current. I thought that Vick was asking about a GFCI fed from the secondary panel. We agree that a GFCI would function if that panel were illegally bonded. If that were the case, would the GFCI operate completely normal or would you think there could be some problems with that? Jim |