Q&A: Inducing an Electric Current on the Sabbath
Inducing an Electric Current on the Sabbath
Question
Have a good week, Rabbi,
I have a trash can at home that opens electrically by passing a hand over it. This mechanism can be turned off before the Sabbath, and then the lid can be lifted manually. The problem is that when you lift it manually, it causes an induced current in the motor responsible for opening the lid, and that causes a very faint flicker in the LED lights on the trash-can lid. Is it permitted to open the trash can manually on the Sabbath in such a situation?
Best regards,
Answer
I think so. Although at first glance this seems to be an inevitable result that one does not care about, involving a prohibition that in the view of many is rabbinic (and in my view perhaps Torah-level. But a weak flicker that is of no use at all is not a Torah prohibition, because there is no issue here of building). But in my opinion even that is not present here. This is just unintentional involvement with no purposeful act. You are opening a trash can, and the fact that something else happens in parallel is a separate matter. Like walking past lights that turn on by sensors.
Discussion on Answer
That is more problematic. The light is actual light, so it is an inevitable result involving a Torah-level prohibition.
It even serves you a bit during the day too, so perhaps it is beneficial to you.
And this is also a case of turning on something that is not merely incidental involvement but an unintended act. It is built into the refrigerator, and functionally its opening turns on a bulb.
According to this, if I forgot to switch off the refrigerator light so that it turns on every time I open the door, am I allowed to open the refrigerator because I don’t really need the light? (Let’s say there is daylight.)