Overpower consumption protection too sensitive?

Axelv

Hi!

I've recently connected a Shelly 1PM to my hot tub to be able to control it. It's connected on one phase, 230V, and according to the manual it is 16A. It has a 16A fuse in the central fuse box.

Now, when idle, meaning heating and low circulation but not fully turned on, the hot tub draws 2.8 kW according to the Shelly. When the jets are turned on, the Shelly shows 4.2kW for a second, then turns off by overpower consumption protection. 4.2kW translates to 18.3A.

My reasoning is that if the fuse never broke before, it is not really drawing more than 16A, but possibly momentary as the motors are starting. I know faintly about capacitive loads, which I guess one phase motors are, but not enough to understand if I'm making some wrong assumptions here. The Shelly is rated for 16A, but maybe should not be used with such a heavy load? I tried disabling the overpower protection, but it is still not accepting the high load.

So I guess my question is if I really should be using the 1PM for this use case, or if there is a better alternative? It is interesting to see the power draw, but more important to be able to turn on and off via timer and remotely.

66er

Your problem is the inrush current peaks.

You can use an inrush current limiter, but you have to look for one that is approved for these currents!

GravityRZ

And please note these inrush current limiters are basically a resistor with a high resistance when cold and a low resistance when hot.

these do get very hot and need their dedicated enclosure.

i have them for my infrared sauna to limit the starting current in the winter(light bulbs will get lower resistance the colder it gets)

DerAutomatiker

Or you use a Shelly EM with a contactor.

mezaw

I too have set up a Shelly 1PM today to control my hot tub.

It worked for an hour or so, then the shelly cut out with an over current protection notification. I disabled the overcurrent protection on the device in the shelly app.

I checked back an hour later and the tub is off and the shelly unresponsive.

I've turned the power off and on a few times but I can't get any response from the shelly, and thus now can't turn the tub back on.

The tub has a 3kw heater, and the pump appears to draw around 350w according to the shelly.

What's going on?

How do I get my shelly back on again?

I wonder if it's just not up to the job. It would be a shame as I'm using (well, intended to) a temp sensor on the 1PM to measure the tub temp.