[RFI] Galaxy Grow Light Ballast Update

[Tom Thompson]

I did an LTSpice simulation of switching 120 volts through a 600 uH 
inductor into an 8 ohm load.  The inductor delays 30 amps  of current 
through the load by 600 microseconds and 15 amps by 200 microseconds.  
Even with the fast switching speed of a magnetic breaker, the delay is 
insignificant.  I think the best magnetic breaker switches in about 3 
milliseconds.

Also, the human body will never draw enough current to flip a normal 
breaker.  On the other hand if a person touches the hot wire of a GFCI 
protected circuit while in contact with a ground, the person will 
unbalance the current in the hot-neutral circuit and trip the GFCI if 
the current imbalance exceeds 10 to 20 milliamps.  This protects human life.

Tom   W0IVJ

On 2/1/2016 2:58 PM, Jim Brown wrote:
> On Mon,2/1/2016 1:19 PM, Tom Thompson wrote:
>> I respectfully disagree.  The choke in the green wire and the common 
>> mode choke both are 300uH.  A short circuit current between the hot 
>> and the green wire would pass through both chokes in series. At 60 Hz 
>> the total impedance is 0.2 ohms which is not going to affect the 
>> breaker or fuse blowing.
>
> But it's NOT 60 Hz, it's an impulse. And if the choke is effective at 
> killing RFI, it's got significant resistive impedance at the 
> frequencies of that impulse.
>
> The question is not WILL it blow the fuse/breaker, but will it blow 
> FAST ENOUGH to protect someone from electrical shock.
>
> 73, Jim
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