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Figure F.1 – Measurement of ribs

Figure F.1 – Measurement of ribs

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61439-1 © IEC:2009



– 105 –



Example 1






IEC 1496/05



Condition:



This creepage distance path includes a

parallel- or converging-sided groove of any

depth with a width less than X mm.



Rule:



Creepage

distance

and

clearances

are

measured directly across the groove as shown.



Example 2

≥X mm



IEC 1497/05



Condition:



This creepage distance path includes a

parallel-sided groove of any depth and

equal to or more than X mm.



Rule:



Clearance is the “line-of-sight” distance.

Creepage distance path follows the contour of

the groove.



Example 3

=X mm



IEC 1498/05



Condition:



This creepage distance path includes a

V-shaped groove with a width greater than

X mm



Clearance



Rule:



Clearance is the “line-of-sight” distance.

Creepage distance path follows the contour of

the groove but “short-circuits” the bottom of the

groove by X mm link.



Creepage distance



61439-1 © IEC:2009



– 106 –



Example 4



IEC 1499/05



Condition:



This creepage distance path includes a rib.



Rule:



Clearance is the shortest air path over the top of

the rib. Creepage path follows the contour of the

rib.



Example 5







IEC 1500/05



Condition:



This creepage distance path includes an

uncemented joint with grooves less than

X mm wide on each side.



Rule:



Creepage distance and clearance paths are the

“line-of-sight” distance shown.



Example 6

≥X mm



≥X mm



IEC 1501/05



Condition:



This creepage distance path includes an

uncemented joint with grooves equal to or

more than X mm wide on each side.



Clearance



Rule:



Clearance is the “line-of-sight” distance.

Creepage distance path follows the contour of

the grooves.



Creepage distance



61439-1 © IEC:2009



– 107 –



Example 7




≥X mm



IEC 1502/05



Condition:



This creepage distance path includes an

uncemented joint with a groove on one side

less than X mm wide and the groove on the

other side equal to or more than X mm

wide.



Rule:



Clearances and creepage distance paths are as

shown.



Example 8



IEC 1503/05



Condition:



Creepage distance through uncemented

joint is less than creepage distance over

barrier.



Rule:



Clearance is the shortest direct air path over the

top of the barrier.



Example 9



≥X mm



≥X mm



IEC 1504/05



Condition:



Gap between head of screw and wall of

recess wide enough to be taken into

account.



Clearance



Rule:



Clearances and creepage distance paths are as

shown.



Creepage distance



61439-1 © IEC:2009



– 108 –



Example 10



=X mm



=X mm



IEC 1505/05



Condition:



Gap between head of screw and wall of

recess too narrow to be taken into account.



Rule:



Measurement of creepage distance is from

screw to wall when the distance is equal to

X mm.



Example 11



d

≥X



C´ Floating part



Clearance is the distance d + D



Clearance







D

≥X



IEC 1506/05



Creepage distance is also d + D



Creepage distance



61439-1 © IEC:2009



– 109 –



Annex G

(normative)

Correlation between the nominal voltage of the supply system

and the rated impulse withstand voltage of the equipment 2

This annex is intended to give the necessary information concerning the choice of equipment

for use in a circuit within an electrical system or part thereof.

Table G.1 provides examples of the correlation between nominal supply system voltages

and the corresponding rated impulse withstand voltage of the equipment.

The values of rated impulse withstand voltage given in Table G.1 are based on the

performance characteristics of surge arresters. They are based on characteristics in

accordance with IEC 60099-1.

It should be recognized that control of overvoltages with respect to the values in Table G.1

can also be achieved by conditions in the supply system such as the existence of a suitable

impedance or cable feed.

In such cases when the control of overvoltages is achieved by means other than surge

arresters, guidance for the correlation between the nominal supply system voltage and the

equipment rated impulse withstand voltage is given in IEC 60364-4-44.



———————

2



This annex is based on Annex H of IEC 60947-1.







66/115



120/208

127/220



220/380, 230/400

240/415, 260/440

277/480



347/600, 380/660

400/690, 415/720

480/830







100



150



300



600



1 000



AC r.m.s.



50



V



Maximum value of

rated operational

voltage to earth ,

a.c. r.m.s.

or d.c.



660

690, 720

830, 1 000



347, 380, 400

415, 440, 480

500, 577, 600



220, 230

240, 260

277



115, 120

127



66







AC r.m.s.



1 000



480



220



110, 120



60



12,5, 24, 25,

30, 42, 48







960-480



440-220



220-110,

240-120







AC r.m.s. or d.c. AC r.m.s. or d.c.



Nominal voltage of the supply system

( ≤ rated insulation voltage of the equipment)

V



12



8



6



4



2,5



8



6



4



2,5



1,5



0,8



6



4



2,5



1,5



0,8



0,5



Load

(appliance,

equipment)

level



Distribution

circuit level



Origin of

installation

(service

entrance)

level



1,5



II



III



IV



Overvoltage category



4



2,5



1,5



0,8



0,5



0,33



Specially

protected

level



I



Preferred values of rated impulse withstand voltage

(1,2/50 μ s) at 2 000 m

kV



Table G.1 – Correspondence between the nominal voltage of the supply system and the equipment rated impulse withstand

voltage, in the case of overvoltage protection by surge-arresters according to IEC 60099-1



– 110 –

61439-1 © IEC:2009



61439-1 © IEC:2009



– 111 –



Annex H

(informative)

Operating current and power loss of copper conductors

The following tables provide guidance values for conductor operating currents and power

losses under ideal conditions within an ASSEMBLY . The calculation methods used to establish

these values are given to enable values to be calculated for other conditions.

Table H.1 – Operating current and power loss of single-core copper cables

with a permissible conductor temperature of 70 °C

(ambient temperature inside the ASSEMBLY : 55 °C)

Spacing at least one

cable diameter



Conductor arrangement



Single-core cables,

Single-core cables in a

touching free in air or

cable trunking on a

on a perforated tray.

wall, run horizontally.

6 cables

6 of the cables

(2 three-phase circuits) (2 three-phase circuits)

continuously loaded

continuously loaded



Single-core cables,

spaced horizontally

in free air



Crosssectional

area of

conductor



Resistance

of conductor at

20°C,

R 20 a )



Max.

operating

current

I max b )



Powerlosses per

conductor

Pv



Max.

operating

current

I max c )



Powerlosses per

conductor

Pv



Max.

operating

current

I max d )



Powerlosses per

conductor

Pv



mm²



mΩ/m



A



W/m



A



W/m



A



W/m



1,5

2,5

4

6

10

16

25

35

50

70

95

120

150

185

240



12,1

7,41

4,61

3,08

1,83

1,15

0,727

0,524

0,387

0,268

0,193

0,153

0,124

0,0991

0,0754



9

13

18

23

32

44

59

74

90

116

142

165

191

220

260



1,3

1,5

1,7

2,0

2,3

2,7

3,0

3,4

3,7

4,3

4,7

5,0

5,4

5,7

6,1



15

21

28

36

50

67

89

110

134

171

208

242

278

318

375



3,2

3,7

4,2

4,7

5,4

6,2

6,9

7,7

8,3

9,4

10,0

10,7

11,5

12,0

12,7



8

10

14

18

24

33

43

54

65

83

101

117



I max = I 30 × k1 × k 2



0,8

0,9

1,0

1,1

1,3

1,5

1,6

1,8

2,0

2,2

2,4

2,5



2

Pv = I max

× R20 × [1+ α × (Tc − 20 °C)]



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Figure F.1 – Measurement of ribs

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