13Amp smart plug > tripping fuse

lowrisk

I have a few samsung SmartThings plug (13a), I don’t have issue with them except for one which often trip the fuse when I turn the plug on.

this plug don’t even have a big load, I mean when I turn it on usually the load is under 30w…. (and no more than 200w when I turn on my computer on).

when I add more load to the plug it doesn’t trip the fuse but just when I turn in the plug sometime ….

it’s seems that the fuse itself is for the office but also for the shed outside, where a another 13a smart plug is connected to a EV granny charger (the load is 2200w, and I’m pretty sure that the granny charger is 10a anyway).

I just don’t understand why turning on the plug will trip the fuse since it’s only add a few watts, and when I turn the fuse back one, everything work, even if I turn in my computer (<300w)

the socket on my office (where the plug is connected) seems to be coming from a extension lead from the utility, will I better plug my smart plug just after the extension lead instead of in my office ? (I assume it’s make thing worse since the load would be higher since it will connect to more stuff)

also how many amp In a fuse/circuit breaker in Ireland ?

10-10-20

With a load of 10A, I personally would not have a smart plug operating on that device. These plugs aren't designed for continuous high-current switching and you'll possibly find that the contacts within the internal relay will become damaged over time if it's switching 10A unsynchronised to the mains frequency (ideally switching heavy loads should use a thing called "zero-point crossing" to prevent arcs).

Additionally you are adding yet another electrical connection onto the cable - something's going to give and you need to reduce the overheating risk rather than increasing it.

When you say that you're tripping the fuse, what type and rating is this fuse which trips and does it happen if the EV granny-lead is disconnected too? It could be an inrush current problem... you might be teetering on the edge of a trip anyway, but inrush current into your PC & monitor may just be an amp too far.

kirk.

Ya as above , I would just use them for light loads you can safely switch remotely , definitely not car charging.

Computer equipment ? Not sure of the use for smart plugs there either

lowrisk

https://www.boards.ie/discussion/comment/118572071#Comment_118572071

Thank you for your reply and sorry for the delay, it's weird because I had the same issue this morning when the EV wasn't plugged... nothing was on really (the EV have a 13amp extension lead with an RCD but I suppose that has nothing to do with that).

I know the 13amps smart plug behind the granny charger is dodgy, I use it for tracking the electricity usage for the last few months, I'll can remove it I suppose.

I removed the smart plug from my Office side (the one which give me the problem) and I'll check if the problem is the same or not.

For the fuse, I don't really understand, to be honest, I'm in Ireland for over 10 years but I'm still used to the old French fuses but here's a picture.

Stupid question but since most UK 3-PIN plugs have fuses integrated into the socket, would the issue be from the socket itself? (Well I'll guess I find out after a few days with that smart plug)?

Andrea B.

https://www.boards.ie/discussion/comment/118582595#Comment_118582595

Hi, in case you are displaying a general image of your board, could you post a specific one to show the module that is tripping. In case RCD or RCBO?

If a 20A MCB, it as simple as the fact that this specific smartplug is faulty?

lowrisk

https://www.boards.ie/discussion/comment/118585159#Comment_118585159

It's one of the module from the right of the pictures (X Pole PLSA-B20"), hard to tell which one since they don't have any label.

so it's a 20a ? so everything down the line only have 20a? anyway in my situation I'm pretty sure the issue is from my "smartplug" not the one on the EV but the one behind my computer, I removed yesterday and since no issue at all.

Thanks for your help

10-10-20

https://www.boards.ie/discussion/comment/118582595#Comment_118582595

To get techy on this... all fuses/breakers have different tripping characteristics. MCB's have two types of responses - an overload and short-circuit. Depending on the current being taken an overload can take seconds to hours to trip a breaker, while a direct short-circuit should be near-instantaneous. You'll find these nice graphs describing this in each of the MCB's specifications.

Fuses are more simplistic devices but again react relatively similarly to the situation.

But also remember that plug-fuse is only there to protect the cable - the cable to your device is often rated for ~5A or 10A, but the electrical circuit from the consumer board is rated for 20A but is capable of transferring a lot more current when it's in an overload state. That's why we fuse the plug - to protect the cable. And of-course that small plug fuse won't react if the fault is upstream (nearer to the consumer-board).

Anyhow, all of this is pointing to a fault on the smart plug. I'd continue to isolate it and perhaps think of a different way of monitoring the EV charge rather than using an in-line smart-plug (such as using a CT-clamp https://shop.shelly.cloud/shelly-em-50a-clamp-wifi-smart-home-automation-1#139). Finally you should consider moving to an EV charge-point to ensure that the electrical load is taken off the plug circuit.

Andrea B.

https://www.boards.ie/discussion/comment/118585664#Comment_118585664

Nice kit!

Do they have a cloud fee?

10-10-20

Ha! Funny you should ask - but mine are all isolated on a private network and connected to Home Assistant - so no cloud here. This is showing my meter box, but I'll have one on my EV charger too soon.

From reading about it anyway, it looks like it's free and enables remote management through the app.

https://shelly.cloud/support/cloud-connected/

lowrisk

https://www.boards.ie/discussion/comment/118585664#Comment_118585664

thanks a lot that's I learned a lot.

I'm only renting so I can't go with a EV station for now but I will definitely setup one or two when we move (we have two EVs).

it's funny how the EV is getting random current, but anyway limited to 2200w max it's hell... (especially for a 78Kwh battery....)

the Shelly is a great idea thanks a lot, I was looking for Aeotech for a while, I don't know why I didn't think about Shelly. I do have a old smappee box which do about the same but I never connected her since I never managed to find the right connection on my fuse box but I suppose I could connect it to the module!

anyway I probably gonna order some Shelly, I'm using Home Assistant too, it's a good thing that the this CT-clamp is using WiFi because I already have 3335 Zigbee entities I don't think I could add one more haha

10-10-20

Glad to assist. Shelly are great - I'm not a fan of Aeotech's HEM though - it's all too much traffic over the z-wave network and it also seems unstable to me.

On the point of the randomness of the charge - part or all of that is down to the variation of the voltage supply as the voltage will rise and fall depending on the local demands. Mine is like this:

So if your car pulls 10A continuously, to convert this wattage you need to multiply it by the voltage at that instant.

10A * 234v = 2340W

10A * 242v = 2420W

So you see some variance over time.