Sylvia is right, at first glance. But all is not
necessarily revealed by reading Table 5B and assuming ยง5.3.4
applies.
The referenced column in Table 5B, Part 1, is for
secondaries within ELV/SELV voltage limits to chassis and
between independent secondary circuits of 'similar' circuit
types.
BUT ... one must be careful and read all of the applicable
kibbles and bits.
For instance, in reviewing Table 2G, Figure 2F with Table
5B:
1) an ELV Circuit and an unearthed SELV Circuit are within
the same voltage limits where the referenced column of Table
5B seems to apply
2) assume the ELV Circuit has Basic Insulation to a Primary
Circuit
3) also assume the SELV Circuit is unearthed
4) Figure 2F indicates ELV to unearthed SELV requires
Supplementary Insulation (S1), but there's no Supplementary
EST value in Table 5B
5) Table 2G, for S1, refers to Condition 2 of that table
6) Table 2G, Condition 2 states that the worst-case voltage
involved for the Basic Insulation is used to determine the
insulation requirements, in this example, between the ELV
Circuit and the Primary Circuit
7) the ELV Circuit to unearthed to the SELV Circuit
requires an EST based on Supplementary Insulation in one of
the five columns (two through six) of table 5B
If this example is faulty, someone let me know.
Regards,
Peter L. Tarver, PE
[email protected]
> From: Sylvia Toma
> Sent: Friday, December 05, 2003 11:00 AM
>
> There is no test for Basic, Supplemental, or
> Reinforced insulation since
> for those three categories; you need to meet the
> spacing requirements.
>
> For Functional insulation, you can conduct hipot
> test in lieu of spacing per sub-clause 5.3.4.
>
>
> From: Jim Eichner
> Sent: Friday, December 05, 2003 10:15 AM
>
> I have a question about 60950-1 based on what I
> suspect might be an error.
>
> In Table 5B listing voltages for hipot tests, the
> second last column from
> the right shows a 500V test for Functional
> insulation but no test for Basic,
> Supplemental, or Reinforced insulation. Is this
> an error or am I missing
> something? It seems to me that this should be reversed.
>
> Thanks,
>
> Jim
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