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19.5 The test of 19.4 is repeated on class 0I appliances and class I appliances
% c* m0 ?" i' P5 Q3 A& e: n+ Iincorporating tubular sheathed or embedded heating elements. However, controls are not
" f/ M: D" r0 r- t: I8 _& s8 Pshort-circuited but one end of the element is connected to the sheath of the heating element.
& w/ T0 Z o2 w$ I- t: EThis test is repeated with the polarity of the supply to the appliance reversed and with the . I: Y, g, g7 q; Y- V) z$ f
other end of the element connected to the sheath.
! {$ p; l. M. j$ N2 mThe test is not carried out on appliances intended to be permanently connected to fixed wiring $ |' b! p1 m6 y, v* E( n
and on appliances where an all-pole disconnection occurs during the test of 19.4. 0 V5 y a6 Y$ Y
Appliances with a neutral are tested with the neutral connected to the sheath. * [7 f& v t$ o* q
NOTE For embedded heating elements, the metal enclosure is considered to be the sheath.7 Z7 z8 ]4 `! `
什么意思三相三线的取暖器需要测试吗
& s, v0 ?9 L3 N# o) w& C' U4 Z怎么测试
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