house ground question..

[lamplight]

Hi

i recently discovered our house ground (grid connected AC) wasnt working.. its connected to a copper water pipe about 5' below ground level through our field stone foundation.. it had corrodoed completely off... this morning i got a new zinc plated ground clamp, sanded the pipe to expose some shiny copper and reconnected it. I tested some of the outlets upstairs that i jnow have properly grounded outlets and it seems all good. I have two questions:

can i coat the ground clamp and around it on the pipe in petroleum jelly to prevent more corrosion like we do on battery terminals?

and:

I also have an offgrid solar system with a pure sine wave inverter that has no grounding on that system of any type.. i was thinking of connecting the ground cable on the sine wave inverter to my houses's ground which i now know is working.. is this ok? basically i want the ground plugs working on my solar's AC as i run alot of expensive equipment on it: computers, etc..). id like to see my computers "line fault" light go off... and also to have the ability to plug into the ground for static discharge if needed when working on electronics/computers..

thank you!

[niel]

hi matt,
that's a good question if it's legal to do that or not as i'm not sure. i do know that the connection can loosen and if it did the coating material could migrate between the connector and the rod. maybe use 2 connectors and retighten them after at least 6 months before applying something like that. i do assume this will be underground and not visible to an inspector otherwise let it go if above ground and just check it for tightness and condition every so many years.

ground connections are supposed to be carried forward to the main breaker box from a gt inverter. this means for a 240vac gt inverter that there will be 4 wires going to the main breaker box. 2 hots, 1 neutral, and 1 ground. btw the neutral to ground connection must only occur in the main breaker box.

[inetdog]

Hi

i recently discovered our house ground (grid connected AC) wasnt working.. its connected to a copper water pipe about 5' below ground level through our field stone foundation.. it had corrodoed completely off... this morning i got a new zinc plated ground clamp, sanded the pipe to expose some shiny copper and reconnected it.

There is a large part of your problem! A zinc coated ground clamp is meant to be used on galvanized water pipes. For use on a copper rod or pipe you need a brass or bronze ground clamp.
Electrolytic (galvanic) corrosion between the zinc and copper will eat away at all points where the two touch. It will be strongest if they get wet or exposed to high humidity, but that is not necessary for damage to happen.

[lamplight]

ok I'll go get another clamp that's not zinc.. hardware store had no idea... I thought I'd mention that just for that reason.. it's working fine but I understand may corrode.. will go get something else tomorrow..

Neil re: my inverter it is not grid tie at all in any sense.. it's just an offside sine wave inverter that's connected to solar batteries.. the ac output from that is in no way connected to my grid tie AC.. so given that...,can I share the ground?

[RCinFLA]

Yes, you need a brass clamp. Zinc and copper along with some moisture make a good battery.

[niel]

"Neil re: my inverter it is not grid tie at all in any sense.. it's just an offside sine wave inverter that's connected to solar batteries.. the ac output from that is in no way connected to my grid tie AC.. so given that...,can I share the ground?"

well that depends. if they already connect the neutral and ground at the inverter then that's a no go and to disconnect it and run the wires separately should not be problematic with that particular inverter for if it is problematic then don't do it. a separate ground wire and rod is a possibility though if it is in no way connected to the other normal ac wiring. you need to research your manual as to what it says on grounding before even thinking of what this ol fart says.

[lamplight]

thanks neil.. I did look at manual before posting.. I didn't understand what it was saying.. will post what it says re: grounding..

[CDN_VT]

There is a large part of your problem! A zinc coated ground clamp is meant to be used on galvanized water pipes. For use on a copper rod or pipe you need a brass or bronze ground clamp.
Electrolytic (galvanic) corrosion between the zinc and copper will eat away at all points where the two touch. It will be strongest if they get wet or exposed to high humidity, but that is not necessary for damage to happen.

Yes, you need a brass clamp. Zinc and copper along with some moisture make a good battery.

From this Thread:
http://www.wind-sun.com/ForumVB/show...161#post126161

Brass IS Copper & Zinc
Bronze IS Copper & TIN
All vessels (boats) that have brass thru-hulls ,will not be insured if a claim is made 4 a flounder. Bronze fittings below water line.

~~~~~~~~~~~~~~

And from being a sparky tech (IBEW) Bronze is the clamp only .. all other metals could fail an inspection
Brass is not allowed in Code.

VT

Edit add:
As I read here, Fuels /CNG & LPG need the correct gas piping & lines plus FORGED nut's ..
If you pay for insurance , then build to code, cuz the fittings don't burn , and inspectors are sticklers !!

Just sayin

YMMV

[lamplight]

ok.. guess I better find out what code wants for MA

[CDN_VT]

Attachment 3702

This is one I was referring to : link is web site Sir.

VT