I made a 13.8V 10A linear power supply from a transformer took from a computer UPS whose battery was dead. Now the issue is when I touch the output of the regulator leads, or the power supply casing I felt a slight tingling sensation. I measured the voltages using a multimeter with one lead referenced to earth and got these readings,
negative rail and earth = 34 VAC
positive rail and earth = 34VAC
Casing and earth = 15VAC
some parts of the transformer and earth =15VAC.
This stray voltage was interfering with my other circuits I'm testing. Fortunately I was able to solve the problem by earthing the case and the output rails directly, but I still read a 1 to 2 Volts on my DMM. How is this effect happening? How do I get rid of this completely? Also I can read a 700mV on a 1N4148 RF detector probe in the close proximity to my PSU when ever I touch it or attach a 10cm wire to it. Is it just static from all the switching devices in my house or does it have to do anything with the PSU.
Here is the schematic,