Control 230V pump with UNO

Hello i want control 230V pump with my arduino but i dont know how exacly do this. I think about relay or transistor. Someone can guide me into topic?

Anyone that equates using a transistor to switch 230V AC, shouldn't be allowed near that kind of voltages to do anything except connect a plug in a wall socket or reset the circuit breaker.

The ideal thing to do is to use a relay, but not just any relay... you need to know the load of the motor in the pump. And in case it is something close to industrial grade, you need to think about an emergency stop switch for it.

You might be talking about an aquarium pump... and that, although dangerous, isn't as dangerous as a well pump, but since we don't know it's hard to advise in a safe way on what to get and how to use it.

If you can provide more info, I'm sure plenty of people can help you... but remember that IT IS DANGEROUS!!!!

Yes, be VERY careful with the 230V volt part of this. Put the relay near the pump, and run only a signal circuit to Arduino. An opto-isolated relay or "Solid State Relay" would be best.

This is overkill with number of relays, but they are optically isolated: (DISCLAIMER: From my shop, but there are other suppliers too):

A 230V pump would put quite a load on your system at start up so a 30 amp relay minimum would be required but you would really have to calculate amperage maximum otherwise you can end up frying your system and potentially start a fire.

Opto-isolated relays would be best otherwise you could end up doing the floppy on the floor like the cod fish we catch over here in east coast Canada when they are out of the water.


I am a fan of “Home Easy” wireless sockets (and a range of other products). They are easily interfaced with an Arduino using a <£5 RF module and offer complete protection in terms of the Arduino user not messing with mains voltage. A wireless socket costs about £10.

They are rated for 3kw or 13A at 230v - which also happens to be the max rating for the 3 pin plug used here. We have no clue about the size of the pump - why are people making the mistake of equating voltage with power? There's a 230v pump in the pond up at my parents house. It's something like 60w. This wouldn't be a problem in the slightest. Bear in mind that the OP was considering a transistor for control AC - hence my conservative suggestion to use a product that maximises their safety.

When did the OP state that it's a big pump? My washing machine, dishwasher, pressure washer etc etc etc all have 230v pumps and plug into a mains socket. The OP has obviously been scared off anyway.....

There's info on answers... including 230v answer from the PowerTail Switch people... to this at...

Motors and devices drawing heavy current need a well built relay and should be installed professionally.

This should do it. About $80.00 US. Safe and reliable.


The relay pictured below (or seen in the link in the last message posted) is in a panel that can be locked.

The energizing coil is activated using 110V and is capable of switching up to 220v and 60 amps of current. What this means of course is that you can use the "switchtail" between the wall outlet (110v) and the 110v cord leading into the panel. This allows you to safely turn the coil on and off using your arduino uno or whatever.


I would like to revive this thread since I have the same requirement. Fortunately I have detailed info on the motor I need to control. (attached)

The original control box has a crappy 24v timer ($80 X2 this past summer alone) that blows every time the power goes out. I would like to create my own Arduino UNO solution but have been having trouble finding info…

Thanks for any you can provide!


Do you know what the rated load current of your "crappy timers" was? please attach or link to a datasheet if possible.

It would be quite easy technically to do what you are looking at, however there may be all sorts of legal/insurance ramifications and BIG safety issues, depending on your electrical skill level, local laws and regulations or Insurance requirements.

You will need the UNO, a RTC (Real Time Clock) and a suitably rated SSR or Contactor, the SSR is preferred as they have the opto isolation required and can be directly driven by the UNO. If you only need the pump to switch on every few hours, as opposed to at set times, then you won't need the RTC.

230 volt equipment merits respect but there is no need to run screaming from the vicinity; at least it doesn't jump at you like high voltage does. So I stress the "respect"

There should be no problem controlling it from the Arduino. Just use a bit of engineering when designing the interfacing equipment. I would use an HP (horsepower) rated contactor rated for the motor horsepower and voltage on the load contacts. It will be big enough to require an interposing relay driven by, say a FET or MOSFET switch from the Arduino. So we have the interposing relay, coil voltage to suit the MOSFET, say 12 or 24 vdc and contacts rated to suit the contactor closing coil, probably 220 vac then the contactor. Above all use snubbers on the coils both to prevent arcing on the contacts and to reduce electrical noise. I've seen no mention of a snubber in this forum but it is only a series resistor/capacitor connected across the coil, resistor say 100 ohm 10W and capacitor .1 mfd and 600v. I know this watts and volts sounds like overkill but when I made a living designing industrial controls all kinds of strange problems disappeared when we started using snubbers on every coil in sight.