I'm trying to help someone out on Quora. They need to switch a fan running off a 120V/25A service, and wish to use a smart switch.

Now such switches don't exist, but those that do could easily switch a relay that does the heavy lifting. I just do not know how one would do this and still be safe and to electrical code.

Would anyone have a thought where I could point him?

 

Anything over 50v has to be in a recognized enclosure with correct circuit protection, fusing etc and all metallic surfaces be earth grounded.
The nature of any low voltage supply also has to be known.
Max.

 

Is everything else in place, a 25A circuit with a breaker? Not that I have a solution, but if that’s not in place then there are bigger problems.

 

Anything over 50v has to be in a recognized enclosure with correct circuit protection, fusing etc and all metallic surfaces be earth grounded.
The nature of any low voltage supply also has to be known.
Max.

That is a given. From what I know one may not simply piece together components, even those listed, without the overall component also being certified.

Meaning I can get a metal box to hold a relay, wire and ground it, use BX cables and such, and still have a non code compliant unit. That is why I did not recommend this approach to him, though I may do such in my own home (but have not).

I'm not quite sure if the terms here it has been a few years since I was investigating such equipment building (low voltage solar power for an isolated light house).

A listed enclosed relay would be a great find.

 

The closest commercial product I can think of is used in home theater, where a 12v signal can be used to turn on various components. Even that’s not common and I can’t imagine a 25A rating.

Every smart switch I’ve seen tops out at 15A.

 

Any off the shelf home automation system that can turn on and off an appliance could be modded to turn on and off a relay instead, and done up to code with no problem.

The trick really is the interface between the smart switch 120 volt output and the relay enclosure, nothing Mickey mouse here.

If you don’t know how to comply with the codes in your area, then this is not a project for you.

 

How about a 5-12Vdc output wall-wort plugged into a smart-switch, with the wall-wort powering an SSR.
That way the only external high voltage is the fan connection going to the output of the SSR.

 

Any off the shelf home automation system that can turn on and off an appliance could be modded to turn on and off a relay instead, and done up to code with no problem.

Unfortunately, once you modify a listed item it is no longer usable in any system that must pass NEC code.

How about a 5-12Vdc output wall-wort plugged into a smart-switch, with the wall-wort powering an SSR.

Fine, except how does one mount a SSR to code within a structure? The guy I'm helping here is running a roof vent fan or such. Not a box on a table connected with a power core (which does not have to follow NEC code) but hard wired into his building, which needs meet NEC code.

 

Wouldn't an SSR in a NEMA enclosure suffice?

 

In HVAC you have a 24V thermostat handling large loads, a very similar problem.

A random example is https://www.ebay.com/itm/Cadet-10-K...ric-Heating-Relay-with-Integral-/223186574525

A more careful search of HVAC gear could turn up something more suitable, but it's where I would look.

 

Wouldn't an SSR in a NEMA enclosure suffice?

That is a fine design to start with. But it needs certification to be listed to meet codes.

In HVAC you have a 24V thermostat handling large loads, a very similar problem.

That is one area I have been searching. Usually I find this stuff, but this is a bit elusive.

 

What exactly is a smart switch. Does it have an ip address? There are wireless motor control contactors for 25 amps at 120 V. Code rated.

 

What exactly is a smart switch. Does it have an ip address?

Yes, but only on the LAN where it resides. The means to access them from the WAN vary. Some devices require a local hub or a website to handle the security aspects of connecting remotely. It's an IoT switch.

 

ok...thanks.

 

I have controlled my smart devices from the next county.

Yes, it does depend on the code behind them. In this case, the app on my phone knows the IP in my house and sends the commands as needed.

What exactly is a smart switch. Does it have an ip address? There are wireless motor control contactors for 25 amps at 120 V. Code rated.

Would you have a source or part number? I spent some time looking for one but lack the magic key words.

 

https://www.amazon.com/Remote-120VAC-Motor-Reversing-Control/dp/B001PNIKJO

It came up in a "wireless 120V AC motor controllers" or something close, on startpage search engine.