An integral, unitary pre-expanded cover assembly unit for covering an electrical connection between first and second electrical cables (40, 50) each having a primary conductor, the pre-expanded cover assembly unit comprising: a cover assembly in a folded position or state including: an elastomeric outer sleeve defining a cable passage to receive the electrical connection and the primary conductors of the first and second cables (40, 50), the outer sleeve comprising an intermediate section and first and second outer sections (110A, 110B), wherein the first outer section is folded at a first annular fold and is on the intermediate section, and wherein the second outer section is folded at a second annular fold and is on the first outer section; a first retention layer between the intermediate section and the first outer section of the outer sleeve; a first friction reducing layer between the first retention layer and the first outer section of the outer sleeve; a second retention layer between the first outer section and the second outer section of the outer sleeve; and a second friction reducing layer between the second retention layer and the second outer section of the outer sleeve; and a removable holdout mounted within the outer sleeve, wherein the holdout is operative to temporarily maintain the outer sleeve in an expanded state; wherein: the cover assembly is movable from the folded position or state to an unfolded position or state by sliding the second outer section of the outer sleeve in a first axial direction away from the intermediate section of the outer sleeve and by sliding the first outer section of the outer sleeve in a second, opposite axial direction away from the intermediate section of the outer sleeve. a cover assembly in a folded position or state including: an elastomeric outer sleeve defining a cable passage to receive the electrical connection and the primary conductors of the first and second cables (40, 50), the outer sleeve comprising an intermediate section and first and second outer sections (110A, 110B), wherein the first outer section is folded at a first annular fold and is on the intermediate section, and wherein the second outer section is folded at a second annular fold and is on the first outer section; a first retention layer between the intermediate section and the first outer section of the outer sleeve; a first friction reducing layer between the first retention layer and the first outer section of the outer sleeve; a second retention layer between the first outer section and the second outer section of the outer sleeve; and a second friction reducing layer between the second retention layer and the second outer section of the outer sleeve; and an elastomeric outer sleeve defining a cable passage to receive the electrical connection and the primary conductors of the first and second cables (40, 50), the outer sleeve comprising an intermediate section and first and second outer sections (110A, 110B), wherein the first outer section is folded at a first annular fold and is on the intermediate section, and wherein the second outer section is folded at a second annular fold and is on the first outer section; a first retention layer between the intermediate section and the first outer section of the outer sleeve; a first friction reducing layer between the first retention layer and the first outer section of the outer sleeve; a second retention layer between the first outer section and the second outer section of the outer sleeve; and a second friction reducing layer between the second retention layer and the second outer section of the outer sleeve; and a removable holdout mounted within the outer sleeve, wherein the holdout is operative to temporarily maintain the outer sleeve in an expanded state; wherein: the cover assembly is movable from the folded position or state to an unfolded position or state by sliding the second outer section of the outer sleeve in a first axial direction away from the intermediate section of the outer sleeve and by sliding the first outer section of the outer sleeve in a second, opposite axial direction away from the intermediate section of the outer sleeve.