Protective device for low-voltage lines

A protective device for low-voltage lines of a cable which is fitted to a cable connection head including two contact junctions for connecting in parallel two conductive wires of each cable line to two conductive wires of a switching exchange, each of said contact junctions comprising two spring contacts each having a first end elastically applied against the first end of other and a second end connected to a line wire or an exchange wire, respectively, said protective device comprising:

• overvoltage protective means for each pair of a line wire and an exchange wire connected through a contact junction, each overvoltage protective means having a first terminal and a second terminal;
• and
• a two-sided printed-circuit board for supporting said protective means;
• said printed-circuit board comprising:
• a pair of first conductive strips opposite each other on the two sides of said board for connecting said first terminal of said overvoltage protective means for a line and exchange wire pair to said first ends of said two spring contacts of a junction of said head, after a portion of said board supporting said two first conductive strips is inserted between said two spring contacts of said junction and without unwiring said line and exchange wires of said pair with respect to said second ends of said two spring contacts of said junction;
• and
• a conductive layer extending the entire length of the body of said protective device for connecting said second terminals of all of said protective means to ground referenced voltage through connecting means which are secured to said printed-circuit board and to said cable head.

A protective device for low-voltage lines of a cable which is fitted to a cable connection head including two rigid stationary connections for connecting in parallel two conductive wires of each cable line to two conductive wires of a switching exchange, said protecting device comprising:

• overvoltage protective means for each pair of a line wire and an exchange wire, each overvoltage protective means having a first terminal and a second terminal;
• conductive spring contacts secured to body of said protective device and applied against said rigid stationary connections of said head when said protective device is fitted to said head, each conductive spring contact connecting said first terminal of one protective means to a rigid stationary connection of said head;
• and
• conducting means secured to said protective device body and extending along the entire length of said protective device body for connecting said second terminals of said overvoltage protective means to ground referenced voltage through connecting means which are secured to said protective device and to a ground element of said cable head.