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参考一下UL2021:
; V* P8 A/ L- K( ]) e15.2 Protection of wiring- ^+ M S. ^$ d9 n" C% n3 X
15.2.1 The wiring and connections between parts of a heater shall be protected or enclosed, except that& M5 o* ^% f6 n4 G
a length of flexible cord may be employed for external connections, or for internal connections that may/ v+ Y1 r1 @ [1 ]8 S
be exposed during servicing, if flexibility of the wiring is essential.1 ]3 f8 l4 C; R& N. {$ ~ E
15.2.2 The internal wiring of a heater in the vicinity of a lampholder that accepts either an infrared lamp& Y7 p5 w0 n& c6 w4 P
or an ordinary lamp:
9 `" H6 ]% \1 B3 S, qa) Shall be a jacketed type at least equivalent to Type SP-2 flexible cord. Asbestos-insulated
1 U8 S4 y6 J5 x hwiring and appliance wiring material is not acceptable unless provided with sleeving or tubing.2 ^. D. Q h" H; z/ |7 W
b) Shall be routed along the metal surface of the heater enclosure and shall be so secured as% ^) J" E! |( o* [! o# F; t4 m n7 G
to minimize the likelihood of its being hooked or grasped.
3 ?: f, ]0 _5 F8 I15.2.3 A conductor utilizing beads for insulation shall not be used outside an enclosure.8 }, Z2 k7 V% T: z% }# s% b
15.2.4 Internal wiring that is exposed through an opening in the enclosure of a heater is considered to be
% [7 X# ~9 `. P5 s* c; sprotected as required in 15.2.1 – 15.2.3 if, when judged as though it were film-coated wire, the wiring4 n, Y- L0 Z: `) J$ l
would be acceptable according to 7.17– 7.20. Internal wiring within an enclosure is acceptable if, even
' ^5 v- c- w- y- _ gthough it can be touched with the probe, it is so protected or guarded that it cannot be grasped or hooked
4 [8 q0 E# y/ Z+ bin such a manner that it could be subjected to stress. |
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