scope:

This specification covers fused and fuseless protectors consisting of insulating base, arresters (air gap or gas filled), fuses and covers (when applicable), terminals for connection to line, instrument, ground and mounting facilities.

The protectors covered by this specification shall be of the following styles (see 3.1 and 6.2.2):

^1/ - Without cover, with arresters, type A1 or A4, and fuses, class F1.

P2^1/ - With metal or plastic cover, arresters, type A1 or A4, and fuses, class F2.

P3 - With plastic cover, arresters, type A2 or A3, fuseless.

P4 - With plastic cover, arresters, type A2 or A3, and fuses, class F2.

The arresters covered by this specification shall be of the following types (see 3.1 and 6.2.2):

A1^1/ - Carbon block (not fail safe) containing a discharge block and an insulating block containing a discharge electrode.

A2 - Carbon disc, fail safe (FS), providing permanent grounding of sustained high over- currents by utilizing a fusible disc or spacer.

A3 - Gas tube, fail safe (FS), providing permanent grounding of sustained high over- currents by utilizing a fusible disc, spacer, link or other suitable means.

A4^1/ - Gas tube (not fail safe) used primarily in protectors which include fuses.

A5 - Gas tube, 3 electrode, fail safe feature incorporated.

The fuses covered by this specification shall be of the following classes (see 3.1 and 6.2.2):

F11/ - Fibre or ceramic body with threaded terminals.

F2 - Ceramic body with dowel terminals.

intended Use:

Protectors covered by this specification are intended for use primarily in ground communication circuits for limiting lightning surges and other excessive currents.