Go Down

Topic: 230v relay with arduino (Read 1 time) previous topic - next topic


May 17, 2019, 07:21 pm Last Edit: May 17, 2019, 07:22 pm by Pipo123
The brown and yellowgreen wire are untouched and i split the blue wire, put one end in the com port of the relay and the other one in the NO port. At the end the wires are just hanging freely as well. There is no consumer at the end

What would happen if i touched these 10V? Would there be a current that could give me a serious shock?


May 17, 2019, 07:32 pm Last Edit: May 17, 2019, 07:32 pm by PerryBebbington
What would happen if i touched these 10V? Would there be a current that could give me a serious shock?
Probably nothing.

Do I take it from that that it is connected to the mains?

A multimeter has a very high input impedance. The blue wire from the relay to the end of the cable runs alongside the live brown wire and is capacitively coupled to it. A tiny bit of the mains will leak into the blue wire and a tiny bit of that will make it across the insulation on the board and in the relay, it doesn't surprise me that you MM can pick it up.

When I said 'probably nothing', that assumes nothing is actually faulty, that there is no connection to live that you are not aware of. One of the rules I have when working with live mains is to always assume that I missed something, that I made some mistake I am not aware of, that there is something I didn't see or think of that might be dangerous. I also put my left hand behind my back so I cannot accidentally make a circuit from one arm to the other across my chest and so my heart. It helps to be right handed and have your heart on the left of your chest too.


It is conected to the 230v ac. Yes (don t know what the mains are. Did you mean that by mains?)

Yes that s a good thing as well to operate with one hand only i agree :)


May 18, 2019, 10:41 pm Last Edit: May 18, 2019, 10:42 pm by Watcher
The general setup as shown in the pictures suggests that you dont have the skills to be messing with mains voltages.
There are  numerous safety and electrical wiring rule violations.

I would strongly suggest to try achieve your goal with lower voltages , perhaps 24v ac.

All solenoids, water valves etc are also available for 24v.


Hi All,
That looks like a quality and standard design digital meter.
It probably has an input resistance of 10 megohms. What is
being measured is a leakage current and not an actual voltage.
(I was surprised when I first came across it.) A leakage of
only 1 microamp will read 10 volts on a meter like that.

Go Up