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参考一下UL2021:
R( t H4 W a9 h15.2 Protection of wiring" u# T3 l0 | c$ O, N. k
15.2.1 The wiring and connections between parts of a heater shall be protected or enclosed, except that r9 }. A( i$ s# J+ N
a length of flexible cord may be employed for external connections, or for internal connections that may
# A- v* i# a; S2 ^' a- Wbe exposed during servicing, if flexibility of the wiring is essential.
9 f* k: L6 e. h: |( Y15.2.2 The internal wiring of a heater in the vicinity of a lampholder that accepts either an infrared lamp' v9 S% \6 [3 x" G' K
or an ordinary lamp:
/ J$ Y% I" I( r( }: J- Ca) Shall be a jacketed type at least equivalent to Type SP-2 flexible cord. Asbestos-insulated
2 k5 E+ K" o/ l2 ^wiring and appliance wiring material is not acceptable unless provided with sleeving or tubing.
/ z9 q3 D1 C3 W6 f: Bb) Shall be routed along the metal surface of the heater enclosure and shall be so secured as
; F( H* u3 l Dto minimize the likelihood of its being hooked or grasped.
/ K$ H' g) v: o+ k$ E15.2.3 A conductor utilizing beads for insulation shall not be used outside an enclosure.
7 H$ O1 U+ l2 G; Q15.2.4 Internal wiring that is exposed through an opening in the enclosure of a heater is considered to be" L5 e l' g2 ]6 }/ E% E
protected as required in 15.2.1 – 15.2.3 if, when judged as though it were film-coated wire, the wiring
3 B* _# P' k1 G( C" E; p3 Gwould be acceptable according to 7.17– 7.20. Internal wiring within an enclosure is acceptable if, even
/ F6 r+ U4 J: a. Zthough it can be touched with the probe, it is so protected or guarded that it cannot be grasped or hooked" @& U& g1 I6 X6 A- ~
in such a manner that it could be subjected to stress. |
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