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19.5 The test of 19.4 is repeated on class 0I appliances and class I appliances6 T" Z9 S5 P; q: z
incorporating tubular sheathed or embedded heating elements. However, controls are not
4 a' ^, t, d5 z8 C8 ]. {- {short-circuited but one end of the element is connected to the sheath of the heating element.
! [- {, f* Q# UThis test is repeated with the polarity of the supply to the appliance reversed and with the , `" \* V0 a$ S' m5 c5 \$ g
other end of the element connected to the sheath.
/ |" `3 B' N- w {2 DThe test is not carried out on appliances intended to be permanently connected to fixed wiring
3 }: i6 {5 y8 s7 {1 a. \3 Mand on appliances where an all-pole disconnection occurs during the test of 19.4.
0 c# Y% c2 k4 I5 Y5 B) L ?# d5 |2 d- o1 VAppliances with a neutral are tested with the neutral connected to the sheath. . x* N3 A% f3 o$ z
NOTE For embedded heating elements, the metal enclosure is considered to be the sheath.
0 k, h/ q# z! p& i/ o什么意思三相三线的取暖器需要测试吗
9 T& J; h3 E/ \! `/ |4 O( |2 G0 l怎么测试/ W" w; R( P0 [$ }" B
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