Entertainment Center: TVs, Stereos, VCRs and DVDs - Unacceptable leakage current from TV
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06-09-01, 04:01 AM
I have a one year old Panasonic 29" TV, TX-29AK1, which may be a UK-only model. It has no earth connection on the power cord. We get a significant electric shock from all exposed metal parts and all connectors - which hurts but does no serious personal damage.
I have measured this voltage relative to earth - when the set is on standby it's an AC voltage at mains frequency close to the mains supply voltage(220V in the UK) with short-circuit current of 300uA. I haven't measured the voltage that this will give rise to across a human being, but it should be about 50VAC, which is definitely unpleasant, which is why I can't get anyone to connect themselves long enough to measure the voltage.
When the TV is turned off there is no leakage, and when it is fully on the leakage is 150VAC.
My dealer insists that he can't find the fault, and Panasonic UK tell me that the dealer will know how to test for mains leakage, but they won't give me figures for the acceptable leakage limit (voltage and current). They also suggest earthing the TV, which would be masking the symptoms rather than fixing the fault.
If I can demonstrate that the current is outside the limit I might be able to convince the dealer of the fault. This may not be easy as I keep having to repeat that it is not "static", and may not even get as far as an AC ammeter. Aargh!
Does anyone know where I can find leakage regulations for TVs or for general domestic electrical appliances?
I have measured this voltage relative to earth - when the set is on standby it's an AC voltage at mains frequency close to the mains supply voltage(220V in the UK) with short-circuit current of 300uA. I haven't measured the voltage that this will give rise to across a human being, but it should be about 50VAC, which is definitely unpleasant, which is why I can't get anyone to connect themselves long enough to measure the voltage.
When the TV is turned off there is no leakage, and when it is fully on the leakage is 150VAC.
My dealer insists that he can't find the fault, and Panasonic UK tell me that the dealer will know how to test for mains leakage, but they won't give me figures for the acceptable leakage limit (voltage and current). They also suggest earthing the TV, which would be masking the symptoms rather than fixing the fault.
If I can demonstrate that the current is outside the limit I might be able to convince the dealer of the fault. This may not be easy as I keep having to repeat that it is not "static", and may not even get as far as an AC ammeter. Aargh!
Does anyone know where I can find leakage regulations for TVs or for general domestic electrical appliances?
Smokey
06-10-01, 11:37 AM
Good Afternoon, clickie:
Boy! Have I seen this one before! The problem is not with the set. The problem is in your electrical panel. I would make a guess that the neutral on your house is not earth grounded. On a 220 volt system, you have two hot wires and a neutral. If the neutral is not grounded, you have the "floating" electrical impact of having about 50 volts AC on any and all ground surfaces in the set.
Do not ground the set! If you do, the entire house will use that ground and then you have all sorts of grief.
Check the electrical panel for this one.
Smokey in the Colonies ;)
Boy! Have I seen this one before! The problem is not with the set. The problem is in your electrical panel. I would make a guess that the neutral on your house is not earth grounded. On a 220 volt system, you have two hot wires and a neutral. If the neutral is not grounded, you have the "floating" electrical impact of having about 50 volts AC on any and all ground surfaces in the set.
Do not ground the set! If you do, the entire house will use that ground and then you have all sorts of grief.
Check the electrical panel for this one.
Smokey in the Colonies ;)