Grounding conductor element for switchboard terminal blocks comprising a conductor body and a spring, the conductor body comprising: - a conductor lamina extending in a longitudinal direction (X-X) and designed to electrically connect together two wires in the longitudinal direction; - a substantially vertical shaped body extending in the longitudinal direction (X-X) having a top edge connected in a transverse direction (Y-Y) to a longitudinal edge of the lamina with which it forms one piece, said body having a bottom body section with: • a longitudinally direction (X-X) extending bottom free edge which comprises a first edge section (123a1) for resting in the vertical direction (Z-Z) on a first flange of the two folded flanges (B1,B2) of a DIN-standard rail B; • a first end which is proximal to said first edge section (123a1) and the bottom edge of which has a tooth for engaging with the first one of the two folded flanges (B1, B2) of the DIN-standard rail; • a second end opposite to the first end and designed to form a means for engaging and retaining the spring; wherein the bottom resting edge has a second edge section (123a2), proximal to said second end; characterized in that the second edge section (123a2) of the bottom edge is aligned in a vertical direction (Z-Z) with the first edge section, for conductively resting in the vertical direction (Z-Z) on the second flange of the two folded flanges (B1,B2) of the rail; in that said spring is a resilient flat-lamina spring which has a head and two flat-pin legs which are separated by an interspace and have respective free ends, wherein said second end for engaging with and retaining the flat-lamina spring has a first edge inclined at a suitable angle (α) with respect to a top, horizontal, longitudinal edge parallel to the said bottom edge and the first edge has a pin extending outwards in the longitudinal direction (X-X) for engagement with a respective seat in the head of the flat-lamina spring, so that the resilient flat-lamina spring 130 is arranged with the same inclination determined by the angle (α) of the first edge to cause the free ends of the legs to make contact with and push from the outside inwards, during use, on the second folded flange of the rail, and wherein the free ends of the flat-lamina spring legs are resiliently deformable for engaging with said second folded flange and to allow operation thereof for disengagement from said rail. - a conductor lamina extending in a longitudinal direction (X-X) and designed to electrically connect together two wires in the longitudinal direction; - a substantially vertical shaped body extending in the longitudinal direction (X-X) having a top edge connected in a transverse direction (Y-Y) to a longitudinal edge of the lamina with which it forms one piece, said body having a bottom body section with: • a longitudinally direction (X-X) extending bottom free edge which comprises a first edge section (123a1) for resting in the vertical direction (Z-Z) on a first flange of the two folded flanges (B1,B2) of a DIN-standard rail B; • a first end which is proximal to said first edge section (123a1) and the bottom edge of which has a tooth for engaging with the first one of the two folded flanges (B1, B2) of the DIN-standard rail; • a second end opposite to the first end and designed to form a means for engaging and retaining the spring; • a longitudinally direction (X-X) extending bottom free edge which comprises a first edge section (123a1) for resting in the vertical direction (Z-Z) on a first flange of the two folded flanges (B1,B2) of a DIN-standard rail B; • a first end which is proximal to said first edge section (123a1) and the bottom edge of which has a tooth for engaging with the first one of the two folded flanges (B1, B2) of the DIN-standard rail; • a second end opposite to the first end and designed to form a means for engaging and retaining the spring;