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Sonoff th16 overload

Hi guys I was debating on doing this or not I recently bought a Sonoff th16 just because it has that extra 6 amp and I was planing on using it to automate my water pump it’s the main water pump that sends the water to my home But the thing is that it has a particular line to supply 250 v I looked up the specs of the pump and it says it draws 11.8 amps so going straight to the point my cuestión is , do you guys think the Sonoff th16 would be able to handle this job some people I have asked told me that it would be better if I use to control another heavy duty that can handle the current of the water pump , however I would like to hear from you guys do you think is good idea to connect it directly to the 250 v thanks hope you can help :)) !

Best Answer

I would highly recommend using an external contactor.  A motor like like has an extremely high inrush current when it is first started (could be several times the full load current for a split second).  Also it is an inductive load which can produce a high ringback voltage when it is disconnected.  My experience with using small relays with heavy AC motor loads is burned and welded contacts.  HVAC contactors are cheap, available in a variety of coil voltages, and  designed to start/stop motors.  The TH will be much happier pulling that little contactor coil than it will be slamming an AC motor.


I have posted several diagrams for connecting contactor relays on this forum.  Do a search and you will find.


Answer

I would highly recommend using an external contactor.  A motor like like has an extremely high inrush current when it is first started (could be several times the full load current for a split second).  Also it is an inductive load which can produce a high ringback voltage when it is disconnected.  My experience with using small relays with heavy AC motor loads is burned and welded contacts.  HVAC contactors are cheap, available in a variety of coil voltages, and  designed to start/stop motors.  The TH will be much happier pulling that little contactor coil than it will be slamming an AC motor.


I have posted several diagrams for connecting contactor relays on this forum.  Do a search and you will find.


1 person likes this

Thomas,


I would never switch more than say 100W through this relay, they are a great device, but their build quality is perhaps open to debate.  Any loads above 100 W always switch through a contactor designed for the  11.8 A or 2700 W load.

Thank you so much you really helped me can you email me the diagrams at diegoduarte915@gmail.com It would be highly appreciated:)))
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