CUSTOMER REQUEST:

Any type of electrical system will require one or more conductor joints. Creating a proper electrical connection is essential for the correct operation of the entire system. So, what rules should be followed to achieve the best result?

OUR SOLUTION:

Electrical connections represent the “hot spot” (a point where electrical resistance increases, causing a localized temperature rise) of a system. If the joint is not made correctly, serious damage can occur, such as material melting and the potential risk of short circuits.

Certain aspects must be taken into consideration, specifically:

• Contact materials: the most common are copper and aluminum. However, direct contact between the two accelerates oxidation due to galvanic reaction. To avoid this, dedicated accessories are used, such as Cu/Al bimetallic washers, or materials with surface treatments (tin plating, silver plating or nickel plating).

• Contact surface: It must be cleaned and polished, removing residues such as oil or grease. Even skin contact can create impurities, so it is best to handle conductors with gloves.

• Contact surface overlap: according to good construction practice, the overlap must be at least 5 times the thickness.

• Hole and screw size/number: when these are not already defined by the system (e.g., connecting a conductor to switch terminals), holes must be of adequate number and size to ensure effective contact pressure. The screw preload must be distributed evenly across the surface, while avoiding excessive material removal from the conductors.

• Screw preload: the correct value corresponds to the tightening torque to be applied to the bolted connection. This torque value is specified in the product’s installation instructions (if not, it is strongly recommended to contact the supplier).A torque wrench must be used.
  Note that too low a torque can lead to imperfect contact and increased resistance, while too high a torque may deform the components. It is also advisable to mark screws and nuts once the correct torque is reached, to facilitate the final inspection.

• Visual inspection: always perform a final check, ensuring there are no anomalies (such as imperfect contact surfaces) and verifying the correct alignment of the markings made during screw and nut tightening.