Ballast for electric jumping

I found many 240V ballast for the Osram 18W downlight (more than 30) and I hooked 3 of the ballast in parallel using a 12VDC power supply, and sometimes I could see sparks jumping(mostly when I touch the terminals and let go it would create a spark). My question is whether which is better, hooking the ballast in series or in parallel to achieve a more powerful spark.


And also what would happen, if I connect the ballast to the mains 240VAC? Would it create a bigger, longer spark?

The electronic ballasts not isolated from mains, no possible the serial connection!

Series