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参考一下UL2021:
6 c; t" l5 P% ]% H* }& ^7 b2 }15.2 Protection of wiring
$ Y: j9 ? T9 c; A15.2.1 The wiring and connections between parts of a heater shall be protected or enclosed, except that
$ J: p* s) p. P5 D+ J) r( [a length of flexible cord may be employed for external connections, or for internal connections that may
9 F/ W3 w$ a+ v9 r5 O S& U9 [be exposed during servicing, if flexibility of the wiring is essential.
7 Z: i5 p7 \$ [( F. j+ P% [15.2.2 The internal wiring of a heater in the vicinity of a lampholder that accepts either an infrared lamp3 X$ e o% A$ m% K7 L# ]
or an ordinary lamp:, m, \) \. f, y4 Q
a) Shall be a jacketed type at least equivalent to Type SP-2 flexible cord. Asbestos-insulated
+ }1 o' J/ y$ R2 r/ ^8 Z5 y) y9 Jwiring and appliance wiring material is not acceptable unless provided with sleeving or tubing.
6 |) N4 G; l- J pb) Shall be routed along the metal surface of the heater enclosure and shall be so secured as
" D+ N# z, |; Y! U' |* j3 y7 X/ Eto minimize the likelihood of its being hooked or grasped.. N$ t+ c$ X V1 _7 F/ x2 H
15.2.3 A conductor utilizing beads for insulation shall not be used outside an enclosure.
' R0 n; a0 F( W. w0 `15.2.4 Internal wiring that is exposed through an opening in the enclosure of a heater is considered to be- x% f1 G. `( y6 X+ }6 G, v( a
protected as required in 15.2.1 – 15.2.3 if, when judged as though it were film-coated wire, the wiring
* Q' q- F" V' |" nwould be acceptable according to 7.17– 7.20. Internal wiring within an enclosure is acceptable if, even
; L" c4 w1 _+ e$ i5 [2 n8 Sthough it can be touched with the probe, it is so protected or guarded that it cannot be grasped or hooked
) P! q0 \/ v5 l8 ain such a manner that it could be subjected to stress. |
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