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19.5 The test of 19.4 is repeated on class 0I appliances and class I appliances' E' a% r b# \2 M' W7 x+ y
incorporating tubular sheathed or embedded heating elements. However, controls are not
" y6 d* o5 _3 d% [short-circuited but one end of the element is connected to the sheath of the heating element.
; P6 d! k! n) w9 h- ]This test is repeated with the polarity of the supply to the appliance reversed and with the + T! e$ V* z; v8 v
other end of the element connected to the sheath. + @* u; v/ X& x: Z6 {* X6 k: E. k
The test is not carried out on appliances intended to be permanently connected to fixed wiring
1 t7 O T K& |0 J8 \and on appliances where an all-pole disconnection occurs during the test of 19.4.
5 G5 ^& v) o9 i9 {& ?Appliances with a neutral are tested with the neutral connected to the sheath. - E3 L" o( c; d" }0 h2 r% S
NOTE For embedded heating elements, the metal enclosure is considered to be the sheath.1 s: e2 }( `5 {& z1 U u% J/ G
什么意思三相三线的取暖器需要测试吗
8 s& N5 B$ A, v% a$ w+ t9 d# S5 v怎么测试
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