I'm helping a friend upgrade two panels on a duplex he owns. The panels are right next to eachother. Each panel will be 100 amp. The plan is to go up with one riser rated for 200 amp and bring that into a gutter. From the gutter, split into two 100 amp panels below.
I'm familiar with grounding for regular single family homes, but in this case I'm not sure if I'm needing to double up all the grounding.
I don't have a ufer so I'll use the water main as the main grounding electrode (it is metal going into the ground), secondary electrode will be a 8' ground rod. Lastly, I'll bond the gas at the hot water heater. All of this will be done in #4 bare wire.
This being said, I'm sure I don't have to put in two ground rods and run two #4 wires to the water for each panel. How is this normally done?
Any suggestions or advice on this would be appreciated... also, what is the differnece between grounding and bonding?
The grounding electrode conductors can be spliced together in the gutter, then one grounding electrode conductor run to your grounding electrode(s), with the size based on a 100 amp service. Of course, the gutter has to be bonded also. Soares book on grounding has good illustrations of this.
Although the code requires gas piping to be bonded, several AHJ's and local gas companies will not allow this.....best to check first.
For our friends in PA & NY, a UFER is a concrete encased grounding electrode, typically rebar within the foundation. The UFER ground system was actually developed during World War II by Herbert G. Ufer, a retired vice president of U.L.
Although some interesting comments I'm not finding this helpful. Example of the kind of explaination I'm looking for follows: Take the Grounding electrode and the conductor from the ground rod to one panel then take a grounding jumper from the first panel to the second panel.
No offense taken. I guess I was looking for someone to say point A goes to point B. I have purchased some electrical books and I am educating myself. This is a very useful board and I intend to use it in the future.
As for the gutter, I'm only following the advice of fellow electricains that have done similar work. I guess the idea is to have one riser. The existing panels are right next to eachother, so it would make sense for the riser to come into the gutter and then each conductor into a landing lug then to the line side of meter.
Byron Your bio does not state your occupation, I am curious why? This leads the pros here to be cautious as to how much info they give, because all the info given to a novice or homeowner will still not be enough. There is so much more to this industry than point A to point B!
For a two family I would use a 2 gang meter socket. One 200 amp riser from that, a hundred amp feeder to each panel. I see no need for a gutter at all. This is all the info I can give as this is NOT a do it yourself project and while it is good to see you trying to learn, this board and some books are not going to make you an electrician. If I lived in that duplex I would not be happy to know the wiring is being done by some handymen. In fact I would notify the local authorities.
LOL very funny. Sorry to misguide you as to thinking I'm a handyman by the fact that I'm helping a friend out. I'm a licensed electrician here in California. This isn't my expertise so I was trying to find some info on grounding multi-family homes. I mostly have done commercial and single family homes. Again, the idea of a gutter with two 100 Amp panels was new to me and thats what I was told to do by fellow electricians as stated in a previous post.