6 M7 c! a" p P' g. x' dQuestion: W0 Q; N+ y6 c( i6 U2 qSome whirlpool baths incorporate a telephone set. Therefore they incorporate a connection to the telephone network, in which it is used voltages exceeding 50 V between the signal lines. Any way, the voltage measured from any line to earth is less than 12 volts. Taking into account that sub-clause 22.35 requires that "parts such as switches and controls accessible to the user in the bath shall only be supplied at safety extra low voltage not exceeding 12 V": 5 p% C8 u( N5 p& @* y1 d- should the signal lines be insulated considering the voltage referenced to ground, in which case the requirement for insulation will not be stringent? $ x4 @6 h3 N' v! p. t# P# `or " c' W$ J: c+ j- should the voltage between the lines be considered instead, in which case the insulation requirements will be more stringent?) v3 f' y0 D9 F% z+ T- ^* A2 |$ `9 ]
Decision: ' N' I9 S+ K- |7 |2 z2 uIf the knobs are directly connected to the telephone circuit, in such a way that the telephone line voltage supply the knobs, this construction is not accepted. & C% G8 x$ [9 D, U+ c! m5 r 4 E9 S% V& V* t* ?[attach]75761[/attach]8 s& u, X* H/ c3 }$ x% a) m: v
DSH 576