Abstract: Device for verifying the tightness of a network of cables with metal sheathing or metal part. This device comprises a central measurement unit (UC) connected to rack units (UBo1, UB2) controlling the assemblies of cables of the network (C1, C2) to which they are connected via terminal boards. The assemblies are disconnected from ground at the head of the network of the assembly of cables (C1, C2) and the insulation resistance with respect to ground of this assembly of cables is measured. The resistance is compared with an adjustable standard resistance. The electrochemical couple generated by a lack of tightness, which is associated with an alarm is also measured. The rack unit (UBo1) at the head of the network is associated with at least one rack unit (UBe1) located at the end of the cable or assembly of cables (C1) in which signals are detected and analyzed.