@IanMe 

 

It has to do with the HS200 not being able to handle more then 600W of incandescent bulbs so if that is divided by the voltage of the switch (120V) you get the amperage which is 5.

@Tony  Yeah, I know how amps and watts are related.

The question is why there is also a 15A rating. 

 

What kind of load can you put on it that's above 5A and below 15A?

If it's not resistive, it would be something like a 12 transformer or switching power supply lighting system, or a motor which might have a *reactive* component to it. Normally devices are rated LOWER for reactive loads than resistive loads.  e.g. a Lutron RA2 switch might be "rated for 6 A of general purpose lighting load and 2 A 0.5 HP of motor load."

 

@IanMe 

 

Different loads would generate a different inrush current. For the incandescent light, its inrush currents can be as high as 15~20 times the steady state currents
According to the calculation of inrush current and steady state current of different types of load, it is necessary to distinguish the rated use current of specific loads (such as incandescent load) and resistive load.

Generally speaking, for a kasa smart switch, the inrush current that can be handled by its rely can bear would be at most dozens of amperes.
So for the general use, the maximum load would be 15A and for a incandescent load, the maximum would be limited to 5A.

 

@JohnDen 

 

No, max is only 15 amps.

I came here to ask this exact same question. Typically, incandescent bulbs are the "base case" since they are purely a resistive load. I did not realize previously that they had a high inrush current, but that does make sense. I guess my question is the same as IanMe. What would be an example of something with a *lower* inrush current? LED's are certainly higher as a ratio to steady state load and I assume CFL's would be as well. See this as an example: https://www.youtube.com/watch?v=Ybdm3SDMORI I think TP-Link's rating of this device as 15a "general purpose" is pretty disingenuous if they are concerned about inrush current as I can't think of any load that could get you to 15a but without any significant inrush current. Incandescent bulbs are about the most basic kind of a load I can think of... Indeed, most other switches out there are rated for 600w incandescent (and much lower for LED/CFL). I suspect the reality is this TP link switch is roughly the same. Also, to JohnDen's question about use on a 20a circuit: If the load is hard-wired in and a known fixed amount I don't see the issue using this on a 20a circuit. Many light switches (dimmers specifically) are rated for much less than a full 15a or 20a and yet they are allowed on 15a circuits. I think where you get into trouble is when you have a switched receptacle where folks could plug whatever they wanted in. I would be curious what the NEC has to say about this and I really would like for TP Link to have more serious technical documentation on this kind of thing. Do note that the NEC does require you to follow manufacturers instructions and so if TP-Link documents that their switch is only good on 15a circuits then that is the answer.