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X1 @( a1 Y9 `8 m ?Question: y' z2 K: N4 d; @% |3 E
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.& s. D; S( w; b8 w5 z* u# g3 Z; z4 r
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?5 ]9 [' u, ?) J8 G+ `# }' x* J
Decision: ]; c$ U D6 H: m. P' `
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..4 E% ~/ }( p, X3 t6 |
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