UNE 21808:1982

APARAMENTA INDUSTRIAL DE BAJA TENSION. DETECTORES DE PROXIMIDAD INDUCTIVOS. FORMA A, DE CORRIENTE CONTINUA, 3 O 4 TERMINALES

LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR FOR INDUSTRIAL USE. INDUCTIVE PROXIMITY SWITCH. FORM A, FOR DIRECT CURRENT, 3 OR 4 TERMINALS.