Question Current leak in smps outer body

[Jin dew]

I have a biostar gt5 racing motherboard powered by 600w masterwatt lite smps. Today 2 phase were down , when power comes back , UPS started beeping crazy trying to turn on. I turn it off and restarted , ups didn't start. I took everything apart plugged smps directly to wall socket and it started showing current in psu outer body . I tested other psu and the later one too showing current in outer body. I plugged it in another socket and still showing current in psu body. The problem is when connected the psu with mobo and other parts, everything is showing current flow. Are my PSUs faulty or anything wrong with earthing that cause current flow in psu outer body? There was never a current leak problem before .

 

[Lutfij]

The MasterWatt PSU isn't exactly something I'd keep inside of a computer. From the looks of your (thread)posting your PSU might be affected due to some faulty wiring in your house or worse that the power from the main electrical poles is tainted.

By your definition of showing current on PSU outer body, are you referring to the unit being grounded when you touch the PSU with bare feet(making contact with the floor)?

 

[geofelt]

What do you mean by "two phase were down" ?
If a psu or a UPS is not properly grounded you can have all sorts of problems.

 

[TJ Hooker]

it started showing current in psu outer body

How have you determined this? I.e. what did you use to measure the ground current and how did you measure it?

 

[Jin dew]

How have you determined this? I.e. what did you use to measure the ground current and how did you measure it?

I didn't measure , i just used tester which is showing current in outer body of smps when connected to wall socket. By phase down I mean power cut. There is proper earthing in my house.

 

[TJ Hooker]

What sort of tester? How is it measuring current "in the outer body"? Does it just show you current flowing on the ground prong (3rd prong) of the power outlet?

 

[Jin dew]

What sort of tester? How is it measuring current "in the outer body"? Does it just show you current flowing on the ground prong (3rd prong) of the power outlet?

I used screwdriver tester and no, there is no current flowing through ground prong of wall outlet.

 

[AllanGH]

You tested between the mains ground terminal and the outer case of the power supply and detected current flow/

Is that a correct re-statement of what you said?

Or....did you test between a PSU output and the case of the PSU? If so, then nothing is wrong.

 

[Jin dew]

The first one is correct restatement , i think power cut happened because of something tripped , which messed up the ground wire of wall outlet because when i plugged it in another room's socket everything was fine , no current leak on psu case or mobo.

 

[AllanGH]

Definitely an issue with Earthing / bonding, at the outlet, or in the branch circuit, then, since the RCD didn't trip.

This is a time to call a qualified electrician to re-certify the circuit.

 

[knreddy.ntpc]

My experience with power adapter SMPS primary AC 240v , Secondary 24v , 4 Amp , DC . If Human body is touched to tip , the leakage is reducing to 12V. Hence I have used 10 nF across -ve to earth , it reduced the undesired ac voltage on secondary side (over required DC voltage) from 49.5v to 34.3 V. Further if 20pF (10pF x 2 parallel) is used, ac leakage reduced to 29.1V. Hence if we connect 22nF or 100 nF it may be reduced to negligible. However relevant isolations , proper installation , protections / insulations to be taken care for the above job.