You will be looking at around 500W output with 6x 1050 Ti + the system. The amount of power drawn from the wall would be higher, but power supplies are rated at the amount of watts they can effectively output and are also rated on the efficiency they are capable of converting higher voltage power form the wall into lower voltage power for your system.
I would recommend at least a high-quality 650W gold-rated power supply. For better efficiency you could go with a higher wattage PSU and/or platinum-rated PSU.
Power supplies perform at maximum efficiency at around 50% utilization. So, using a power supply with double the amount of power needed is the best one to use. Most people on the other hand don't want to pay the extra price for a higher wattage power supply. But, that's up to you.