We have acquired four Intervision-xp-964ec analog cameras for a company. They were without power supply units, just devices.
The cases of cameras says: 12V (max 420mA).
We tested them with a laboratory power supply unit, they are fine.
Now we would like to connect them at different places, maybe even outdoors. The most obvious way is to purchase four 12V 1A power supply units and connect them to 220V power network, but an electrician stated that having 220V cables running outside is not the safest, and he would like to avoid it.
It was suggested that I should order a single power supply unit, which has to be installed indoors and then all four cameras should be connected to it by long wires (up to 150m maximum, I think.)
From school, I remember that if you connect devices in parallel then they shall have the same voltage, but the current (measured in amperes) will be divided. I suggested that in this case it may be fine to order a 12V 4A power supply, but the electrician warned that there may be some losses in the cables during transport.
Which power supply should I order to effectively distribute power to four devices each of which may consume 12V 420 mA and they may be located at maximal distance of 150m away from the general power supply unit?
The distance may be different, a camera may be placed right in couple meters away from the power supply, or it may be located at 100m-150m away from it.