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12.7 Thermal test in regard to fault conditions in lamp controlgear or electronic
: U' p: c1 W* S, P* |8 X3 Y2 r. i+ bdevices in plastic luminaires
; g# P2 E- r5 O' k! ^/ fThe test applies only to luminaires with a thermoplastic housing not fitted with an extra8 s( u9 g, R. ^' H z% j
mechanical temperature-independent device as per 4.15.2.1 U4 f# F3 A" V1 z+ H
/ P7 d; p" n8 {+ V$ h12.7.1 Test for luminaires without temperature sensing controls$ j' O' y. ^+ l- u7 p% E" @* \
The luminaire shall be tested under the conditions specified in items a), c), e), f), h) and l) of
4 k' }/ ?' S6 ]5 r0 q, V$ l9 f12.4.1. In addition, the following also applies.; _- Z) b8 }: C) I8 U% I
20 % of the lamp circuits in the luminaire, and not less than one lamp circuit, shall be" T; S! C: `5 Q
subjected to abnormal conditions (see item a) of 12.5.1).& A& l# |2 T! f! ^6 `4 f
The circuits which have the most thermal influence on the fixation point and exposed parts
1 R: u0 N; s' Q; k; @8 ashall be chosen and other lamp circuits shall be operated at rated voltage under normal0 M1 g, Q5 Z* L V: H$ e/ m( K
conditions.
' w' g% r( X3 b% I: {! e6 oThe circuits subjected to abnormal conditions shall be operated at 1,1 times (the rated voltage
& K5 H; B& J* w3 M% cor the maximum of the rated voltage range). When conditions are stable, the highest winding8 j6 k0 z7 F& {4 a6 V5 L
temperature and highest temperature of fixing points and most thermally influenced exposed! m9 m, R$ I5 s5 {
parts shall be measured. It is not necessary to measure the temperature of small wound1 f! E7 b% B; H8 U
devices that are incorporated within electronic circuits.
0 K- o# t5 r( X+ f/ s0 G5 }Compliance
3 U/ D7 c+ J. J3 iThe values of the ambient temperature and the temperature measured at 1,1 times (the rated6 a) [) X" D J. }! C, i+ ~
voltage or the maximum of the voltage range) are used for the linear regression formula in& _2 A4 d% E. [; P. E
calculating the temperature of fixing points and other exposed parts in relation to a
% h) J0 G! w( p4 y" ~0 L! [# hballast/transformer winding temperature of 350 °C. The calculated value shall not exceed the1 x, ?( X/ R; I, I1 `4 a
temperature of the deflection under load of the material in accordance with method A as
7 K9 J7 C2 m9 N% |7 e1 Jdefined in ISO 75 (1987), Plastics and ebonite – Determination of temperature of deflection
0 `. @: A H) M$ p% l0 `% z" _under load.: E6 w' p2 z' S7 f- b& v
12.7.2 Test for luminaires with temperature sensing controls internal/external to the
3 D) r* e; n- K! q1 Z+ j5 C% }ballast or transformer: l' m' W0 A* u; a) k
The luminaires shall be set up for this test as described in the first three paragraphs of 12.7.1." N8 G- B( M& Q% D! B
) l- I# T* T0 C' `% @6 u) v
The circuits subjected to abnormal conditions shall be operated with a slowly and steadily+ ]3 G; b# S* W) ~+ H8 ~5 y2 _
increasing current through the windings until the temperature sensing control operates.
/ @* h; f7 [9 J5 S) q; v1 uTime intervals and increments in current shall be such that thermal equilibrium between
3 X; ~) I6 M H$ N, k2 z0 Rwinding temperatures and temperature of fixing points and most thermally influenced exposed
3 s( M b. N8 M( U, @ F Uparts is achieved as far as is practicable. During the test, the highest temperature of the spots
/ p7 H+ `) H* P% L' Etested shall be continuously measured.1 ?) i! V% O/ ~1 V6 G; L
For luminaires fitted out with manual-reset thermal cut-outs, the test shall be repeated six
9 [7 d, C% {% \0 b& h. k! Ltimes allowing 30 min intervals between tests. At the end of each 30 min interval, the cut-out
# A3 V6 P7 Q6 i; g; Z6 B0 ishall be reset.8 y) r9 j, A: k m U1 V; G
For luminaires fitted out with auto-reset thermal cut-outs, the tests shall be continued until a% `" `6 x+ _% g2 R; H
stable temperature is achieved.( G, m* z; U5 }$ }# j
Compliance/ M) N8 E0 B7 f' p l
The highest temperature of the fixing points and most thermally influenced exposed parts,
+ ?- A; t% u/ }, Gshall not exceed the temperature of deflection under load of the material according to the% x& z# V' R, u) ~; Y
method A as defined in ISO 75, at any time during the tests for thermal links, manual-reset2 _4 \# K9 f1 L8 R n6 J
thermal cut-outs, and auto-reset thermal cut-outs.
7 d1 h) t, W3 t) B1 h/ [$ [2 zIn applying the requirements of 4.15 and 12.7 the following notes are to be referred to:% R8 I+ `% P! n
NOTE 1 - ‘Fixing points’ means both the fixing points of components and the fixing points of a luminaire to the8 B6 b. r$ a! N; r' O2 {7 ~4 A8 Q# b
mounting surface.7 R5 ~8 [% W# U1 b
4 s P* P! y# v8 z
NOTE 2 - ‘Exposed part’ means the outer surface of the luminaire enclosure.
( ?; V2 u( ?( H; ^- W2 h ANOTE 3 - Measurement of exposed parts is restricted to those parts providing the luminaire/component fixing or0 Z: }+ c0 ?9 z6 i0 N, C" {+ s) l
parts providing a protective barrier against accidental contact with live parts, as required by section 8 of this' n) M! P, R7 w4 n- [3 b. f L
standard.
/ H1 H8 H3 L3 ZNOTE 4 - The hottest part of the thermoplastic material section requiring test is measured. This may often be on# X1 r: O$ w; b* {2 @! W c
the internal surface of a luminaire enclosure not the outer surface.
. C7 W( E1 s: a8 B q5 R- R$ |8 vNOTE 5 - The material temperature limits defined by clause 12.7 are with respect to materials under both T- Z( L& B# [. N: C
mechanical load and no mechanical load.0 k3 f; f# Q/ C" m5 F t) O% |1 [
NOTE 6 - The application of clause 12.7 must be read together with the requirements of sub-clause 4.15. |
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