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参考一下UL2021:
5 Y! c, I, {2 W( ~; t15.2 Protection of wiring
- ~: ^: h1 S. C) z15.2.1 The wiring and connections between parts of a heater shall be protected or enclosed, except that' `1 i/ j9 Q/ J8 S* X# s
a length of flexible cord may be employed for external connections, or for internal connections that may
& t8 G1 C6 E# u5 E& k+ A ?be exposed during servicing, if flexibility of the wiring is essential.
) y& Q3 W& [" ?6 V" C15.2.2 The internal wiring of a heater in the vicinity of a lampholder that accepts either an infrared lamp
5 ?7 R) A* ^% K7 r/ por an ordinary lamp:
) o1 G" W* y, W% x! w& ^6 Ga) Shall be a jacketed type at least equivalent to Type SP-2 flexible cord. Asbestos-insulated
" s% _' Y L( R3 twiring and appliance wiring material is not acceptable unless provided with sleeving or tubing.
) J/ E5 h; A' Y- Y- l: ib) Shall be routed along the metal surface of the heater enclosure and shall be so secured as/ U' N6 }8 b! m9 V9 B% i
to minimize the likelihood of its being hooked or grasped.
: M- k8 g+ i- S2 @15.2.3 A conductor utilizing beads for insulation shall not be used outside an enclosure.8 F# i$ m% _2 Q+ ] s1 c
15.2.4 Internal wiring that is exposed through an opening in the enclosure of a heater is considered to be
5 a, `$ x+ @; q2 g8 y6 lprotected as required in 15.2.1 – 15.2.3 if, when judged as though it were film-coated wire, the wiring
* O: z3 J, Y& j4 {1 {6 iwould be acceptable according to 7.17– 7.20. Internal wiring within an enclosure is acceptable if, even
( |8 I& @5 {% mthough it can be touched with the probe, it is so protected or guarded that it cannot be grasped or hooked
" w: z3 w- u9 z f/ C$ j) A# d: pin such a manner that it could be subjected to stress. |
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