Bare Copper Through Concrete
Bare Copper Through Concrete
(OP)
Does anyone has information on running bare copper cable through concrete? This came up in a job I am working on and my worries are that either the cable or concrete will corode creating a weak point in my ground system or concrete pad,
Thanks
dob






RE: Bare Copper Through Concrete
This bare copper cable that I am passing through the concrete is going to be used as a ground conductor
Dob
RE: Bare Copper Through Concrete
RE: Bare Copper Through Concrete
The uefer grounds are in all new contruction. You tie the service drop ground to the rebar inside the concrete. This makes a very good ground because the concrete conducts pretty well but is also in intimate contact with thousands or square feet of earth due to the intimate rough interface between the concrete and the dirt.
But I am not sure exactly how this is done physically.. Sorry.
RE: Bare Copper Through Concrete
RE: Bare Copper Through Concrete
The copper should not corrode. Moist concrete is a reasonable conductor - a lot better than you might expect. The biggest problem is probably physical damage to the ground conductor during construction.
Erico and others make flush grounding pads that you can install to allow a bolted connection to the ground pad. But these are expensive and a pain in the neck to form and keep in place when pouring the slab or deck. Normally, the bare copper is brought up above the finish grade and a five foot pigtail is coiled up for future connection to building column, equipment, or whatever you are trying to hit.
RE: Bare Copper Through Concrete
When used for ufer grounding the bare copper conductor or the steel rebar has to be in direct contact with concrete. Passing thru a pvc sleeve defeats the purpose.
Ideally it should lie horizontally, within 2 to 4 inches from the bottom of the footing. One end is brought out of the footing and connected to the base of the steel columns. Now you have a nicely grounded steel structure, which should be preferred grounding electrode for the building systems.
If a horizontal 20' long rebar (1/2 inch dia. min.) already exists, a copper conductor is exthermically welded to it and a lead brought out as indicated above.
A mass of concrerete is considered better condcutor than just earth.
RE: Bare Copper Through Concrete
RE: Bare Copper Through Concrete
RE: Bare Copper Through Concrete
I am not an expert in earthing systems but am very apprehensive of passing the copper through concrete or connecting the earth grid to the rebars in any way due to the above concerns.
I also would like to know more about Ufer grounding and specifically how the above concerns are addressed.
RE: Bare Copper Through Concrete
RE: Bare Copper Through Concrete
But bare copper coming out of concrete, even outdoors, is a very common practice, at least in the US. Maybe not the best practice, but common.
rraganuth - the Ufer ground is actually required by the NEC. If you have concerns about the copper to rebar connection, you might want to consult with local corrosion engineers. The copper will have more problems in the soil than in the concrete in most locations.