CSA Engineer I work with is asking for 1000 Vrms dielectric strenght
bet network TNV to SELV circuit. The CR/CL is 2.2 mm.
Moreover, they are asking for reinforce insulation. So, who is right?
Base on table 18 of UL and CSA's binational 950 std, if the test
voltage at the network is 105 V max, peak would be 148 V, plus 48 VDC,
U will be greater than 184 V. Therefore, dielectric strength in this
case should be 1500 Vac for basic or supplementary insulation, or 3000
Vac for reinforce.
In addition, in figure 5a and table 0.1a, it indicates that TNV to
SELV require only basic insulation.
Moreover, in table 5 and 6, assuming that the working voltage falls in
the 210 Vpk range, the B/S clearance is only 1.3 mm for pollution
degree 3 and not 2.2 or 2.5 mm. If it is reinforce, it should be 2.6
mm.
Anybody care to discuss?
Thank You
[email protected]
______________________________ Reply Separator _________________________________
Subject: re: Printed Circuit Board Layout
Author: [email protected] at Supernet
List-Post: [email protected]
Date: 30/09/96 18:13
IEC950 / EN60950 and I assume UL1950 requires a suplementary barrier
between SELV and network tip/ring TNV circuits. ie. 2.5mm Cr/Cl and 1500v
rms electrical strength.
Best regards
Barry Singleton
Approvals Specialist
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Original Text
From: [email protected] (Doug McKean), on 27/09/96 11:01:
Hello Treggers,
Our PCB house has given me a conundrum for T1 Ring/Tip/Ground clearances.
They declare FCC 68 and UL-1950 3rd edition conflict with clearance
recommendations.
I'm not sure to what they refer - test voltages versus recommended
clearances(?).
I have always recommended min. of 0.02" between R-T and min. of 0.03"
between R-G and T-G as I think may have been posted here before.
Before I walk into a rat's nest,
does someone know what they are talking about specific with each standard?
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Doug McKean
[email protected]
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The comments and opinions stated herein are mine alone,
and do not reflect those of my employer.
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