UPS wiring issue

OK so I am using double wiring for my UPS which was working fine. Then I needed to connect another energy saver to the UPS so called the electrician. He just connected the bulb with one of the wires and it was working then but did not work later. I realized if I changed/switched the shoe position it would work so some times there is current in one wire and some times in the other wire and to make it work I have to change the position of the electric shoe. My question is

1. Why does the hot/ neutral wire change? Is the UPS making this happen?

2. Is there a way to fix the hot wire so it is always the same ? or

3. Do I have to use double wiring for any new connection?

4. Is there an easy way to fix this or I have to call the electrician again?

i think ur electrician has messed up with ur wiring cux if u r using double wiring at ur premises then polarity of neutral n phase dont matter now ....... u dont hv look for the polarity case in double wiring at all .........