I will be honest some of your questions are a little scary to me. Is this something your wiring yourself? Or is wiring already there if so take a picture of plug and we can say more.
What a PDU does is allow you to run one cable with a lot of amp's to power multiple miner's. This varies on your voltage and number of amps on which PDU is right for you if any, there are a lot of different options. But basically your PDU plug's into your power outlet and basically split's it where you can power multiple miner's from it (assuming power is there). *Edit Better description then mine I think is here -
https://en.wikipedia.org/wiki/Power_distribution_unit+1
PDU's essentially act as portable sub-panels by providing circuit protection to individual PSU's/miners, eliminating the amount of electrical circuits you need in total, and giving you flexibility in powering miners. Also, if you are hiring an electrician (which I strongly suggest you do) you save considerably on labour and likely materials by running fewer, high amperage circuits to your mining area.