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24 Electrical Spacings7 Z) L* y F0 Q
24.1 The spacing between uninsulated live parts of opposite polarity, and between uninsulated live parts
; {9 M1 a: |' Fand metal that is capable of being grounded shall not be less than 1/4 inch (6.4 mm) through air or 3/88 J/ A4 e' f0 L0 m. g) I
inch (9.5 mm) over surface. The outer wrap of an open core and coil ballast is determined to be an9 |- A9 @3 g g. g
uninsulated live part with respect to this requirement.
& @$ X2 m3 y, x7 w* m4 ~Exception No. 1: The spacing requirements do not apply between uninsulated live parts of a wiring device,
1 ?# T0 ]4 Z! f4 b X0 ]3 Dsuch as a lampholder or switch, and dead metal that is part of the wiring device and including mounting, n/ h/ y; g$ g+ f5 @3 g# d0 e: g
screws, rivets, yoke, clamp, or similar components; or for a portable luminaire provided with a grounding
) l9 P- L' b4 I5 d2 f* rmeans between such live parts and that part of the dead metal surface of the portable luminaire on which
% J) Q; I- x3 p, I5 Dthe device is mounted in its intended manner. See Figure 24.1.
. V6 U3 `+ h) h \Exception No. 2: When an isolated dead metal part is interposed between or is in close proximity to:
9 a8 O9 |6 Q: X2 w1 a8 f- D( ^a) Live parts of opposite polarity;/ O/ a; x7 y2 w$ i$ Y0 ?* a
b) A live part and an exposed dead metal part; or1 O4 x. O; R8 {/ [2 A
c) A live part and a dead metal part that is able to be grounded, the spacing shall not be less
' O+ a6 @: y1 R$ J) d( \than 3/64 inch (1.2 mm) between the isolated dead metal part and any one of the other parts0 Q0 X5 X, t3 H w" g
previously mentioned, provided the total spacing between the isolated dead metal part and the, O" s$ u# a; z0 }
two other parts is not less than 1/4 inch (6.4 mm) through air or 3/8 inch (9.5 mm) over surface.
" ^; f8 P5 s4 P2 d) B$ a9 KException No. 3: The spacing between uninsulated live parts of a Class 2 circuit and between such parts* { A9 J) n* W! r$ q" M$ Z
and dead metal that is grounded in service is not specified.
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+ [. ]9 a! X1 @0 }6 u3 g各位大侠,UL153这章的dead metal part,是不是可以直接理解为非金属部件?2 f% b4 |& Q& a
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