Shelly 3EM Exploded after 15 hours of usage, Shelly Pro better ?

christoph321

Hi,

I got professionally installed a Shelly 3 EM by an Electician in hour house and it was working great for 15 hours. Suddenly in the Moment when we switched off a light there was a big bang , the shelly exploded and the whole house was out of power.

I searched the internet and found similar issues, this seems to happen quite often.

No Problem, I returned the shelly via amazon and I will never buy this Shelly 3EM Model again.

My Problem is: I need such a device to measure power usage. Will the Shelly PRO 3EM be more resistand and stable than the 3EM ? Is it a goog advice to buy the pro model ?

See attached Foto for the damage

thgoebel

Welcome to the forum!

Thanks for your description of the Shelly failure! Was it a neon tube which was switched off?

With some likelihood on of three diodes which rectify the three phase voltage at terminals VA, VB and VC got defective. This causes a three phase short with a lot of short circuit current…

Shelly pro 3EM avoids this failure mechanism: Supply for the device is fed by one terminal only (C); the other two terminals (A and B) are for measuring purposes only. This seems to be a big step for reliability!

christoph321

Thanks thgoebel,

yes, it was indeed a Neon Light that was switched off. Thanks for your quick help. So I will buy a Shelly pro 3 EM and also change the Neon Lights because they are outdated anyway.

thgoebel

Brillant idea to drop the neon light! An earlier change could have saved a Shelly’s 3EM life…