16 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 17
> 4 to 6mA could produce lethal electrical shock. Ground Fault Circuit Interrupter (GFCI)
is used for safety against electrical shock due to leakage. GFCI measures the difference
between the current sent to the load and returned from the load and will trip and
disconnect the power circuit if the difference is > 4 to 6mA. GFCIs are normally installed
in AC Branch Circuits feeding power outlets in wet areas like marine craft, RVs, spas,
hot-tubs, kitchens, washrooms, etc.
As explained earlier, RF noise ltration circuits in SMPS generate intentional Earth
Leakage Current. SMPS are used extensively as DC power sources in modern day
electrical / electronic devices e.g. Audio / Video / Computing devices, power supplies,
battery chargers etc. A single GFCI outlet / GFCI breaker may be serving multiple SMPS
loads and therefore, will be sensing the sum of all the Earth Leakage Currents and, if the
sum is > 4 to 6mA after connecting this unit, the GFCI will trip. In such a case, disconnect
other SMPS based device(s) being served by this GFCI one by one till the net leakage
current is reduced to < 4mA and the GFCI does not trip. Other solution is to power this
unit from a GFCI outlet / GFCI breaker that does not have any SMPS load or power from
an outlet that is not protected by GFCI.
SECTION 6 | Limiting Electro-Magnetic
Interference (EMI)
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