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19.5 The test of 19.4 is repeated on class 0I appliances and class I appliances8 _9 V' J& n6 r. b
incorporating tubular sheathed or embedded heating elements. However, controls are not
2 S( T2 C( b* C* L; S/ Nshort-circuited but one end of the element is connected to the sheath of the heating element., X* ?' t3 P% w5 }. B
This test is repeated with the polarity of the supply to the appliance reversed and with the
3 @$ g9 {7 \; w8 B6 u# u6 {other end of the element connected to the sheath.
% v# b9 C2 {9 O bThe test is not carried out on appliances intended to be permanently connected to fixed wiring
5 o; o. Z* w5 p p }and on appliances where an all-pole disconnection occurs during the test of 19.4.
. o' `1 d7 m( z1 z- _+ W" mAppliances with a neutral are tested with the neutral connected to the sheath. 2 H- v$ N; S4 T1 X. k6 `& _
NOTE For embedded heating elements, the metal enclosure is considered to be the sheath.
; {7 ^* Y! K7 B" X9 @* c什么意思三相三线的取暖器需要测试吗
^, ~9 {9 {4 h7 M5 G怎么测试
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