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) W& B# a& G( ?( H% q; ?1) In case of components mounted on a printed wiring board (PWB) and placed across safety
- x4 u+ }/ Z: K6 |& b+ K$ n/ c% Rinsulation (e.g. reinforced insulation), how to deal with different requirement both for printed wiring/ P; @; g1 x. O" R: p. p% x7 P
material and different group of materials?% o2 V m" |0 v7 P* ?! b; O5 e
2) In case of components mounted on a printed wiring board (PWB) and placed across safety
: \0 o' {" \# Einsulation (e.g. reinforced insulation), how to deal in case of different material group for PWB and
& p) z* g, C# C$ Ncomponents placed on it (e.g. PWB of material group I and relay base of material group IIIa)?
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Decision( A8 s" W& c5 F
1) Column relevant to printed wiring material in micro-environment of pollution degree 1 and 2 can, }7 ~$ e2 C0 i4 W; N. X
only be used when there are no components placed on the PWB, across the investigated insulation.. C% |* E/ H- G j- v
In this case, the column showing the worst case has to be used., E' i) l% S" B0 s5 i$ K
2) In case of different material group both for PWB and components, column showing the worst case
# A& _% c; O2 f( n+ H; ~has to be used.
! X+ O7 l3 s' y; A, q& c( x \Remark: For the scope of these decisions, a component is considered to be in contact with the PWB
Q/ A6 F2 f( W" {/ Q/ w8 L4 eif the surface of the component is located at a distance less than the “X” value indicated in table of+ u; S6 z- O- A8 ^% }' m w
annex B. See enclosed drawings- M- h5 g* l5 v9 w3 d3 m
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发表于 2017-1-6 15:54
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