Using Smart AC Switch to Control DC Circuit—Is It Safe for My DC Setup?

Hi,
Could anybody help me with my design? I am trying to control a switch for a DC circuit.  I am using two type of switches for the control switch. Actually I add smart AC switch to my current working set up. I wonder by using AC switch can damage my DC circuit and DC switch. Please see attachment for details.
  Many thanks in advance for  your help.
       John

John-many questions. Here are some:1. What is the DC voltage?2. What is its source?3. How does the DC connect to the circuit?4. What is your AC voltage?5. What is its source?6. what is a "smart AC switch"?7. Are your switches mechanical, electro-mechanical or solid state?8. Will the AC and DC ever be simultaneously present?

John,You need to make sure that the AC is isolated from the DC signal that will turn the AC switch on and off. I'm hoping that is what your "smart AC switch" does. You do NOT want any direct connection between DC and AC. You may be able to use the same signal to control the DC and AC switches as long as you have isolation between AC and DC.
I strongly encourage that ALL AC connections are well insulated so that you (or someone else) does not accidentally come in contact with the AC since it's hazardous. You can get a nasty shock or worse.

Hi John,
What is your application? Would a relay work for your application for switching the AC? It would provide the necessary isolation (protection) between your DC circuit and the AC circuit and it would allow you to switch the AC using a digital circuit.I see in your diagram you are shorting the positive and negative terminals of your DC circuit, I'm not sure what you're trying to do here. Normally you would place that switch in series with the positive, so that you're just switching the positive on and off (thus completing the circuit) instead of shorting positive and negative.
-Mike

Hi All,Many thanks for answer my questions. I am sorry that my initial description is not clear enough.I am trying to explain again:1) Initial DC circuit (5V) , has  2 connector (+ and -) as you can see as the picture.  That works as a jumper between the two ( you can think of as a computer main-board  jumper). To make the circuit do something, I need to connect this two connectors by a simple wire or jumper, which I call a switch. The DC circuit is also powered by a standard AC power, then convert to DC as in PC computer.
2) I have successfully connected and controlled  by a DC switch, the DC switch circuit operating at  DC 5V source. The power supply for the DC circuit is a standard AC power (220 V).  I can turn on and off the switch. This means when I turn on the DC switch, my DC circuit work as I expected.
3)  Now I would like to add another  AC smart switch (parallel to the DC switch). This switch works as follows: when it is turned on, the wire of the left side is connected to the wire on the right side.  The smart switch means  just  Wifi enable switch, which I can control remotely.  The switch seems to me mechanical of some sort, as I hear a sound when I turn it on.As you can see from the picture, I did not fully connect the two output wires of the AC switch to the DC circuit. I only hijack of  one wire of it to connect + and -. 
I think that (maybe I am wrong) because I did not connect two output wires of the AC switch to the DC circuit, I suppose not AC coming to my DC circuit as not closed circuit. However I am not sure about this. For example: this link https://electrical-engineering-portal.com/using-ac-and-dc-together-in-electrical-system.
Obviously for this to work I need to connect both DC switch and AC switch to  the two connector (+ and -) otherwise how is that possible?   Many thanks for your help,           John
PS: the application is household heating. If you are interested I can explain more.


 

This must be going to proceed it with the following part where having a mix ac and dc switched along with the following part so netgear r6700 review will provide the part easily.

It is the same if the voltage sources are AC, or a mix of AC and DC. Voltage sources at different levels are something you dont want to wire up together. Now, it is possible to *couple* an ac signal into a dc circuit. But you have to design a circuit to deal with all the issues of impedance and frequency and so on. ttrockstars