dominicfhk:
Hmm... well since this is a +/-30A sensor I do assume it is safe to run 30A through the chip... But for my application, the current actually won't go over 5A, so it is not really a concern to me. The thing I am worry about is the voltage cause it is going to be constantly around 100V.
If the current won't go above 5A then you should use a more sensitive sensor to reduce the noise. As others have said, you can get boards that provide better isolation than the one you have. I suggest you use this http://www.ebay.co.uk/itm/1x-ACS712-Module-Current-Sensor-5-Amp-Range-Halleffect-Current-Arduino-PIC-ATMEL-/221087104462?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item3379d17dce&_uhb=1 or something similar.
EDIT: changed URL to refer to one with a better PCB layout.