This is just a warning for everyone. Do not make the same stupid mistake as I did.
I bought an 1500W heater from Home Depot and hooked it with Sonoff Basic. It worked well for several days and today I started to smell something like burned plastic. Immediately did I find that the Sonoff basic was smoking. Luckily I disconnected it before the situation got worse.
Sonoff basic is rated for 10A, so 1500W/110V(in US) ~= 13A. I was too optimistic about the safety margin in the design. It was purely my fault. My other sonoff products worked reliable for years.
Btw, does anyone know is there smart plug rated for higher amperage like 15A?
The community appreciates your warning but know that others have posted the same warning … and it would appear that those who needed to see it, didn’t.
The manufacturer of Sonoff devices doesn’t go the extra mile of having its products pass a recognized industry-standard third-party certification process (like UL, ETL, CSA, etc). To be fair, they’re not alone and it has become quite common to sell devices to consumers that don’t meet the basic safety standards of a traditional toaster or hair-dryer (i.e. overheat protection) and are not tested by any standards body to ensure they fail safely (as you have discovered empirically).
FWIW, some while back, the local Costco was liquidating its stock of CE Smarthome Energy Monitoring Plugs for about CAD$12 for a pack of two. They’re certified by ETL to meet specific UL and CSA standards (printed on the back of the device) and rated to handle “125VAC 60Hz 15A Max. 1875W”. I flashed a bunch of them with Tasmota. Amazon still sells them but at an absurdly high price.
Whatever you choose, I suggest you ensure it’s not merely “CE” rated (a recognized but self-certified certification process that has been dismissed as being as binding as a verbal contract).
The heater will be an inductive load, which would place even further demands on the switch. My reccomendation would be to use a sonoff in combination with a contactor to do the heavy duty switching. A quick look on amazon I found a 63A contactor for £17 (I can’t say anything about the quality, just to give you a starting point).
What @reef-actor said about the contactor is still valid, if you are concerned the inductive current load.
Related question:
Would this work at all to drive/switch 110VAC 13A, or is this a completely different type of switch to begin with, so not OK for the 1500W heater that the OP has? https://www.amazon.com/gp/product/B07587NZTC/
I got the idea browsing around YouTube… See the thing he assembled at around 5:43.
I’m guessing NOT OK for 1500W heaters, but seeking confirmation / comments…
The statement was valid regardless of whether the load is inductive or resistive. Effectively, you’re using the Sonoff Basic’s relay to control a beefier secondary relay; the load’s current flows through the secondary relay.
If you check the linked relay’s spec sheet, it indicates the device can handle a maximum of a 1 HP motor at 125VAC in Form A (relay contact is normally open) but reduced to 0.25 HP if used as Form B (relay contact is normally closed). So how the relay is used with an inductive load determines the relay’s maximum capacity.
