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1 b, T7 M2 v9 S3 DQuestion:6 J- u! w2 p" k- j `
Sub-clause 22.106 of standard IEC 603325-2-21:2002 states that, a closed water heater shall incorporate a thermal cut-out providing all-pole disconnection which operates independently from the thermostat.
6 k: h4 p8 p* e0 f$ \: i& {Can the thermal cut-out and thermostat control the same contactor, when a contactor is used or are two contactors needed, one controlled by the thermal cut-out and one controlled by the thermostat?' ^6 y6 c) V( ]7 N D$ W2 Q
Decision:) Q8 d! P+ g) S3 ]
Two contactors or relays must be used because the contactor or relay may not operate if one set of independent contacts welds closed. See also 19.14 in IEC 60335-1 Ed 4.2..6 c( O7 o2 W# a
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