BCU 480 · Edition 06.07
49
Project planning information
7
Cable selection
7 .2 .1
Use mains cable suitable for the type of operation and com-
plying with local regulations. Signal and control line: max. 2.5
mm
2
. Cable for burner earth/PE wire: 4 mm
2
. Do not route
BCU cables in the same cable duct as frequency converter
cables or cables emitting strong fields.
The connection cables are fed into the BCU housing via cable
glands. The cable glands are equipped with multiple seal in-
serts for cable diameters of up to 7 mm. For two cable glands,
there is one seal insert each for cable diameters between 7
and 12 mm.
Ignition cable
7 .2 .2
Use unscreened high-voltage cable (see “Accessories”). Cable
length: max. 5 m, recommended < 1 m. Screw the ignition
cable securely into the ignition transformer and run to the
burner by the shortest possible route.
The longer the ignition cable, the lower the ignition capacity.
Only use radio interference suppressed electrode adapters
(with 1 kΩ resistor) for ignition electrodes, see “Accessories”.
Do not lay UV/ionisation cable and ignition cables together
and lay them as far apart as possible.
Ionisation cable
7 .2 .3
Use unscreened high-voltage cable (see “Accessories”). Ca-
ble length: max. 50 m. Avoid external electrical interference.
Install as far as possible from mains and ignition cables and
interference from electro-magnetic sources. If possible, do
not lay in a metal conduit. Several ionisation cables can be
routed together.
UV cable
7 .2 .4
Cable length: max. 50 m. Avoid external electrical interference.
Install as far as possible from mains and ignition cables and
interference from electro-magnetic sources. If possible, do
not lay in a metal conduit. Several UV cables can be routed
together.
Ignition electrode
7 .1
Electrode gap
7 .1 .1
Gap between electrode and burner earth: 2 mm ± 0.5 mm.
Star electrodes
7 .1 .2
We recommend using 7.5 kV ignition transformers on burners
with star electrodes.
