Protective housing for an electrical installation and electrical installation including such a housing

An electrically insulating protection box for an electric installation comprising at least one electric busbar, the protection box including at least two casings wherein each casing includes inside surfaces intended to surround at least a part of the busbar at a junction zone, at least 50% of the area of said inside surfaces being a contact surface in direct contact with an electrically conducting element of the junction zone, said protection box being manufactured with an additive manufacturing process, wherein the junction zone includes a fastener element for securing said busbar to an electrically conducting element in the junction zone, and wherein the contact surface includes a hollowed portion that delimits a housing for accommodating a head of the fastener element, and wherein the fastener element comprises a screw.