Grounding/Bonding protocol

[imported_archstenton]

Will be relocating main panel and upgrading house's electrical service since will be adding things like Garbage disposal, dishwasher, bathroom fan, garage wiring, range hood, wanting grounded outlets, etc.. Relocation mainly has to do with asthetics and nuisance. Panel is next to kitchen window/door. Don't want wife getting startled by meter reader all the time plus lots of ugly pipes in the patio.

Currently only ground is from existing main panel in back of house to cold water line(but at least 30 feet of run before water pipe hits earth)

Wasn't planning to rewire all circuits(no existing ground) but as many as feasibly possible.

Will be adding grounding rod at new main panel.

Some questions:

Should I run new grounds from old circuits to this rod, meaning install it asap too, prior to doing a lot of the other work. For instance, if I fool around bonding the gas line or hot water lines prior to this, would the gas line become a defacto grounding source until there is a path to this new grounding rod?

Also, are there any issues with filling conduit with a bunch of grounding wires only. Instead of trying to run a grounding wire completely along the old circuit path(daisy chaiin style), would rather run them separate from the hot/neutral lines and more direct to new panel/grounding source. Are conduit sizing calcs the same?

Also, grounding lighting boxes in ceiling/attic space. Is the best or only method to run new grounding wire from the attic down to to the crawl space and out to the new panel/grounding source. Could I simply tie to the drain waste vents going thru the attic? Safety issues or not effective grounding?

Thanks

[Wgoodrich]

If you have metal water pipe coming from contact with earth for at least 10 feet long then that metal water pipe must be you primary grounding electrode. If you install a new 200 amp panel and you have the metal water pipe entering the home with the 10' of earth contact then you are required by the NEC to run a 4 awg copper wire from that main service panel directly to a two piece ground clamp connected to that metal water pipe WITHIN 5' of where it enters the building. Then the ground rod must be installed as a supplemental grounding electrode also. The water pipe is required to be used as the primary grounding electrode if in contact with earth for a minimum of 10 feet.

If you install equipment grounding wires to existing branch circuits these new equipment grounding are required to be green insulated connected either directly to the grounidng bar of that main service rated panel or to the metal water pipe within 5 feet of where it enters the structure or to the ground rod. These equipment grounding conductors are required by the NEC to be ran as closely as possible to the same route as the exiting branch circuit it serves.

The metal gas piping of the house does not have to have a grounding conductor ran from the panel to that metal gas pipe. The gas piping is considered adequately grounded through the appliance that gas pipe serves. Example the gas furnace has a branch circuit that has an equipment grounding conductor ran with that branch circuit as a part of that branch circuit. That equipment grounding wire bonds the gas furnace to the electrical grounding system. The gas pipe is screwed into the furnace making it also bonded by this same branch circuit equipment grounding conductor serving the gas appliance. Teh NEC says that sufficiently bonds the metal gas piping and no further grounding is required.

Remember that you are forbidden to use the gas pipe as a grounding electrode to serve the structure's main service panel.

I suspect that you will find it easier to run a new romex with a grounding conductor than it is to fish a flimsy single green equipment grounding conductor. In my opinion might as well install new cable instead of adding a single grounding conductor. Suspect you would find this idea easier, faster and just as economical.

If you have a conduit with say 3 20 amp branch circuits single wires hot and white inside a conduit then only one equipment groudning conductor sized equal to the larges branch circuit amp rating may serve all those branch circuits if newly installed and all conductors are run together. When existing the together still applies yet you are allowed some leeway in not exactly mathing the existing branch circuit path but are required to follow that existing branch circuit as closely as possible.

Conduit fill is considered to be filling that conduit just as fast with green grounding wire as with black or white circuit wires with no calculation difference. All are counted filling the conduit equally.

Hope this helps

Wg