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19.5 The test of 19.4 is repeated on class 0I appliances and class I appliances* E1 I% Q4 q3 L2 d* q2 l
incorporating tubular sheathed or embedded heating elements. However, controls are not
0 T( w9 E9 e2 Y' Xshort-circuited but one end of the element is connected to the sheath of the heating element.
Y! l3 e3 P9 t ^( ]. O* h0 iThis test is repeated with the polarity of the supply to the appliance reversed and with the % F/ E8 }/ C/ K& J# z8 S$ N" X3 ]8 [; `
other end of the element connected to the sheath. : z4 d$ c" x* x3 Z0 O
The test is not carried out on appliances intended to be permanently connected to fixed wiring 8 ?9 P! x! a2 j& Y* |" P
and on appliances where an all-pole disconnection occurs during the test of 19.4. : V! g; G/ I- f. t
Appliances with a neutral are tested with the neutral connected to the sheath. / g9 [$ M+ X' J7 f# i
NOTE For embedded heating elements, the metal enclosure is considered to be the sheath., d0 H O' s% B& K# v1 R0 R3 Q
什么意思三相三线的取暖器需要测试吗' t& f1 b- G" |3 W
怎么测试
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