DSH 791 TRFs – Values to be reported
http://decisions.iecee.org/icons/ecblank.gif DSH 791
TRFs – Values to be reported
General
All IEC standards
Standard(s):
All IEC standards
Subclause(s):
General
No. Year
DSH
0791 2010
Category: VARIOUS Developed by: WG4
Subject:
TRFs – Values to be reported
Key words:
- TRFs
- Required minimum value
- OD-CB2020 Ed. 1.7 § 4.6.1
Approved at the 48th CTL
Plenary Meeting, in 2011
Question:
Based on OD-CB2020-Ed.1.7 Sub-clause 4.6.1., it is not allowed to use statements such as “OK”, “meets
the standard”, “more than”, “less than”, or similar instead of the measured value, unless otherwise
specified by CTL.
In certain cases the required minimum value is exceeded by a great margin.
Decision:
In case that the measured minimum or maximum value is exceeding or is below the limit value for
more than 30%, the value given in the TRF should be > or should
be < . The accuracy of the used instruments is in line with CTL
DSH 251B or better.
For example measurement of insulation resistance:
· required 5 M;
· measurement range of test equipment 0 … 10 M;
· the measurement instrument shows full-scale deflexion.
The value given in the TRF should be > 6.5 M.
For example measurement of creepage distance:
- The required creepage distance is 3.0 mm.;
- The real distance is exceeding 4 mm.;
The value given in the TRF should be > 4 mm.
For example measurement of leakage current:
- The current limit is 0.5 mA;
- The real current is below 0.35 mA;
The value given in the TRF should be < 0.35 mA.
The following two situations are allowed:
1 – The meter reading is less than the smallest measurable graduation on a meter scale. For
example, touch current measured was less that 0.1 mA.
2 – In checking creepage and clearance distances with a probe the same dimension as the
requirements. For example, creepage and clearance distances were greater than 0.8 mm.
Standard(s):
All IEC standards
Subclause(s):
General0 C2 ^7
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