The contact resistance is the main variable that defines the energy efficiency of an electrical connection, its stable performance and long term service. It is worth noting that according to the measurements performed in this work, the contact resistance in substation connectors can be several times that of the connector's resistance. To reduce connection losses and thus increase connector's efficiency, it is important to minimize contact resistance, to ensure an efficient connection. The aim of this work is to find out, by means of experimental measurements, the relationship between the different components of contact resistance in substation connectors and the main related variables such as material properties, applied bolts torque, true contact area, or surface's conditions among others. Furthermore, this study proposes a novel surface treatment for substation connectors, which allows reducing the contact resistance. Experimental measurements demonstrate the effectiveness of the novel chemical treatment in improving energy efficiency in substation connectors.