ACS712-30A meltdown, careful!

[italianuser]

I've been using ACS712 modules for a bit of time now, very nice boards, good for both AC and DC current measurements. There's three versions of the chip: 5A, 10A and 30A. I bought a bunch of 30A modules to use them with microcontrollers. One of my first long posts here in the forum was a smoothing algorithm for DC current reading with an ACS712, in order to get a higher accuracy (article here).

Here's two boxes I made, same board, different case (black case is at the mains, white box in my studio):



This is the realtime map with current measurements (1.13A for my studio, 1.78A house total usage):




Now, what happened is this... I use a 30A module to measure my house's current usage. I have an average current usage of about 1A @220V and maximum loads of 10-15A, with rare peaks of 15-18A (and main energy meter trips after about 20 seconds).

Ehm... the connector for the power line on the ACS712-30A module is rated 10A... So it will melt and possibly catch on fire when under >15A for too long.



Solution? Remove the connector and solder wires directly to board.



Full article on my blog: http://electronic.acca3.it/2021/12/29/acs712-module-problems-30a-version/

Enjoy!

 

[Korishan]

Ohhh, so the connector isn't rated for high enough amps, even if the chip can handle the current.

Don't they make those modules without that kind of connector but instead standard screw down connectors with a big philips screw?

Personally, I'd use a split core transformer to measure AC current. That way you don't have to pass current through anything else. Just measure the voltage that comes off of it.

Altho, if these are used for "test boxes", that's different. But in actual production environment, nope, SCT all the way

 

[italianuser]

Yes, that green connector... Haven't really seen other kind of connectors other than this one, didn't search much though.

Uhm, from January I'll be using ACS712 to measure other points in the house (oven, washing machine, dish washer and 2nd floor distribution box). What's good, well, for me, about this chip is that I can measure both AC or DC and I already have the code to interface both DC and AC readings.

 

[Korishan]

This is the difference that should be on those units:

The 30A unit is suppose to have a different kind of connector for the sensor leads.

Here's another style to look for:



You could possibly pull that connector off completely and make a modification kinda like what this looks like:

You might need to have a lock washer and nut on the bottom side, though.