unhin-
dered heat radiation will
be ensured at:
Distance cable from wall,
oor ceiling cm
– For cables laying
side side:
Space least two
times the cable ø
– For cables laying one above the
other:
Vertical space the cable
atleast two times the cable ø
cable length least cm
– Consideration thermal
loss cable, the increased
air temperature suf cient
big and ventilated
rooms
– Protection against direct
heatradiation sunlight etc.e. With increased laying depth the load ratings will mathematically
reduced. Hereby the same temperature and the same thermal earth resistances are presumed.1065
Y
As laying depth, the mathematical distance the cable axis for tringular bunched laying the distance the bundle
axis the earth surface with choised.
Normal operation conditions
Laid Earth Laid Air Indications
1 Multicore cable
1 Single core cable
in direct current system
3 Single core cables
in 3-phase system,
side side, with a
space cable ø
3 Single core cables in
3-phase system
in bundle form1)
– Laid open air, i.
– Air temperature 30°C
Adequate big ventilated rooms,
due that the power loss of
the cable not noticeable
increased
Connecting and earthing of
metal sheaths screens on
both sides
1 Multicore cable
1 Single core cable
in direct current-
system
3 Single core cables
in 3-phase system,
side side, with a
space 7cm
3 Single core cables
in 3-phase system,
in bundle form1)
Bedding sand or
earth shove and if
necessary covering
with bricks, cement
plates with to
light curved thin
covering plastic
Ambient conditions
– Ground temperature at
installation depth: 20°C
– Soil-thermal resistivity
of moist area: 1,0 m/W
– Soil-thermal resistivity
of dry area: 2,5 m/W
Connecting and earthing
of metal sheaths screens
on both ends
1)
in “bunched” triangle touching
arrangement
Conversions factors see
the following tables
as collective laying conditions
see the following tables
● Conversion factors
for laying earth:
– covering hood with air
cavat 0,9
laid conduit 0,85
● Conversion factors
for laying air:
– alternating ambient
temperatures
– collecting laying
conditions
– for laying conduits
– see tables and
indications according
to DIN VDE 0298
LAYING CONDITIONS FOR POWER CABLES
.
Normal operation conditions and indications for deviating operation conditions
