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参考一下UL2021:
2 x% n9 o' K0 Z7 C3 G/ X15.2 Protection of wiring9 z+ o* p( S( a
15.2.1 The wiring and connections between parts of a heater shall be protected or enclosed, except that" E& ?) S, s7 U1 t+ f
a length of flexible cord may be employed for external connections, or for internal connections that may6 p ?7 `7 C2 W' V' s6 H$ ~5 x* L
be exposed during servicing, if flexibility of the wiring is essential.
" E% ?) V* }: [2 X; d7 k( |15.2.2 The internal wiring of a heater in the vicinity of a lampholder that accepts either an infrared lamp4 f8 z$ J$ Y4 M( W. M* H( V+ u7 A# Y
or an ordinary lamp:5 H% O7 E2 s; u6 ]1 ~2 q
a) Shall be a jacketed type at least equivalent to Type SP-2 flexible cord. Asbestos-insulated. Q" \" }2 f* m4 l& R% |8 P/ k* Y/ [
wiring and appliance wiring material is not acceptable unless provided with sleeving or tubing.* O! x* `7 w; Z8 E
b) Shall be routed along the metal surface of the heater enclosure and shall be so secured as
" H$ f8 M' I/ i% x3 c3 Gto minimize the likelihood of its being hooked or grasped.
+ r3 z% ]; I8 y" I9 W Z15.2.3 A conductor utilizing beads for insulation shall not be used outside an enclosure." d8 X1 u6 g4 {; ?
15.2.4 Internal wiring that is exposed through an opening in the enclosure of a heater is considered to be
d4 V- z0 M: S( Yprotected as required in 15.2.1 – 15.2.3 if, when judged as though it were film-coated wire, the wiring: J9 y. C7 ?, B1 A; K
would be acceptable according to 7.17– 7.20. Internal wiring within an enclosure is acceptable if, even7 A8 w9 e, e+ U0 o7 d
though it can be touched with the probe, it is so protected or guarded that it cannot be grasped or hooked
* `- c0 F* G0 J6 k9 Q ~2 cin such a manner that it could be subjected to stress. |
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