
BCU 480 · Edition 03.16l
57
Project planning information
6 Project planning information
6 .1 Cable selection
Use mains cable suitable for the type of operation and
complying with local regulations. Signal and control
line: max. 2.5 mm
2
. Cable for burner ground/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 mul-
tiple seal inserts 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.
6 .1 .1 Ionization cable
Use unscreened high-voltage cable, see page 71
(Accessories).
Recommended cable length: max. 50 m.
Lay cable individually and, if possible, not in a metal
conduit.
Install well away from mains cables and interference
from electro-magnetic sources.
Do not lay together with ignition cable.
6 .1 .2 Ignition cable
Use unscreened high-voltage cable, see page 71
(Accessories).
Cable length for integrated ignition. max. 5 m (16.4 ft).
Avoid external electrical interference. The longer the ig-
nition cable, the lower the ignition capacity.
Lay cable individually and, if possible, not in a metal
conduit.
Do not lay UV/ionization cable and ignition cable to-
gether and lay them as far apart as possible.
Screw the ignition cable securely into the ignition trans-
former and feed it out of the unit on the shortest pos-
sible route (no loops) – use the left-hand M20 plastic
cable gland.
Only use radio interference suppressed electrode plugs
(with 1 k
Ω
resistor) for ignition electrodes, see page
6 .1 .3 UV cable
Recommended cable length: max. 50 m.
Install well away from mains cables and interference
from electro-magnetic sources.
Do not lay together with ignition cable.
6 .2 Ignition electrode
6 .2 .1 Electrode gap
Gap between electrode and burner ground:
2 mm ± 0.5 mm.
6 .2 .2 Star electrodes
We recommend using 7.5 kV ignition transformers on
burners with star electrodes.