NO guarantee as to the accuracy of these values
is given.
And they should be checked against some other source.
Where ever possible the transformer should be mounted near
the light fitting, BUT not within 9 inches to protect the transformer
from heat damage
and to reduce the cable size required from the transformer
to the light fitting.
When wiring 12v fittings either single or
together, it must be remembered that lower voltage means
higher current, ( e.g. 1 x 50W 12v lamp alone requires
4.2 AMPS ).
Therefore, the conductor size of the cable
between the transformer and the fitting is larger than that
used in 240v lighting circuits.
Due to the possibility of voltage drop, the
correct choice of cable is vital. Undervolting by more than
0.6v reduces the efficiency, affects the colour of
the light and may affect the lamp life.
The calculator above will help you make
the correct choice of cable.
DO NOT lay under or encase the cable
or transformer with roof insulation
Supplying more than one lamp from a single transformer
can result in significant volt drop between lamps if wired
in parallel, causing non uni-form illumination across the
run of lamps. To overcome this we recommend using the IB
FS020 fused splitter or a multi-outlet transformer.
Each lamp supply is protected by an anti-surge
fuse which prevents the transformer output from being dragged
down in the event of a short circuit in any one of the fittings
Note: The actual cable size and runs
required to connect several lamps to the same transformer
output must be equal to or greater than total load
of the run
Allowances MUST be made for operating
temperatures outside the above,
for correction factors refer to the full IEE 16th edition
regulations for tables.
