Degree
o Pollution
Groove width X
Minimum values
1 0.0 mm
3 1.
The methods measuring creepage distances and clearances are indicated
in the following examples 11.
Rule: Creepage and clearance distance are measured directly across
the groove shown
Clearance distance:--------— Creepage distance:
. 4.201: Example 1:
< mm
1 1--------------------------- T
Condition: Path under consideration includes parallel- converging
sided groove any depth with width less than mm.20.6.
Fig. These cases not differentiate between
gaps and grooves between types insulation.4 Measuring the clearance and creepage distances
(based IEC 60664-1)
The groove width specified the examples applies
to all examples function the pollution degree follows:
4 Insert 169
Table 4.5 mm
If the associated clearance less than mm, the minimum groove width
may reduced one-third this clearance.
Thefollowing assumptions are made:
- any recess assumed bridged with insulating peg having a
length equal the specified width and being placed the most
unfavourable position (see example 3);
- where the distance across groove equal larger than the
specified width the creepage distance measured along the contours
of the groove (see example 2);
- creepage distances and clearances measured between parts which can
assume different positions relation each other, are measured when
these parts are their most unfavourable position.2.4.5 mm
4 2.25 mm
2 1
