I'm trying to install some smart light switches into my house. I've had a little trouble doing it.

The first one was in the kitchen. Every time I tried, it tripped the breaker in the main panel. I went away for half hour to think about it and tried the breaker again and everything was fine - it worked. Strange, like it sorted itself out.

So I went to try the lounge next and all it did was trip the breaker every time, even after leaving it for a bit like the kitchen.

So I left the lounge and went to try our bedroom again. It just tripped the breaker, so for some reason I went and unwired the lounge and tried our bedroom again and it worked fine. I wired the lounge back together with the old switch.

I've tried every room and none of them except the kitchen and our bedroom will accept the smart switches. What an I doing wrong?

I've posted a picture of our main panel. Does everything look ok in it? Are all those earths suppose to be just bundled together? I've also posted a picture of the inside of the light switch and the back of the new smart

I've added another picture to the post (the last picture) can anyone tell me what the blue and yellow wires are please. obviously the red is the live and the green and black is the ground. but what are the yellow and the blue wires. thanksBreaker Panel]1

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  • 1
    1 - What brand/model smart switches? 2 - Post a picture of the inside of the switch boxes, as the problems are likely there and not in the main panel. 3 - Those are breakers, not fuses (which is good - if they were fuses you normally have to replace them rather than just flip a switch to reset), so that is a panel (presumably your main panel), not a fuse box. 4 - While breaker problems can cause issues with new switches, far more likely is that the problem is how you are connecting the switches. 5 - Yes, the grounds all get bundled together - that is normal. Commented Mar 19, 2019 at 17:57
  • Also, what country are you in? Suspect UK or someplace else other than US/Canada based on colors of the wires. That can affect the answers as color coding of hot vs. neutral can be key to getting things connected correctly. Commented Mar 19, 2019 at 17:59
  • hi thanks so much for your answer. this has been really annoying me seen as I've managed to get two of the smart switches working in different rooms but not the rest. sorry yes I'm in the UK and I've edited the post to add pictures of the light switche and the smart switch. and there Chinese ones so no brand name.
    – Lewis
    Commented Mar 19, 2019 at 19:40
  • Can you post a picture showing how you've wired the smart switch?
    – Mark
    Commented Mar 19, 2019 at 19:53
  • 2
    I only see 2 wires and a ground, how did you power the smart switch it looks like it needs a neutral, what it looks like you have a switch loop a hot and a switched hot.
    – Ed Beal
    Commented Mar 19, 2019 at 20:08

1 Answer 1


You don't have neutral in that box!

Yellow/green is the one wire whose color code is is standardized worldwide: yellow/green, green or bare.c It always means safety earthing.

Anywhere you might have used those for neutral, you must correct that. Whoever taught you that is wrong, and full of shortcuts which are unsafe.

Misusing ground for neutral is what's causing the breaker trip. Even the ones that "seem to work" are still a problem and will still tend to cause trips.

The black wire is also not neutral. Since there are only 2 wires besides earth, the two wires can only be supply always-hot, and switched-hot to the lamp.

In this box, there is no neutral because it is a switch loop. However it also looks like in surface conduit, so it may be feasible to open up the conduit and change the cable to 3-core+earth, which can include neutral.

Regardless, those switches are wrong here

Since you don't have neutral, you need smart switches which support lack of neutral. I recommend going down to the local Wickes and seeing what they have.

The switch in your picture will not do. It is a cheap Chinese no-brand thing that you mail-ordered or bought from a dodgy shop who smuggled them in. Note the complete lack of certifications by any reputable testing lab such as TUV or CSA. See the CE and RoHS marks? That is not any promise by the importer that they self-certify, and are taking legal responsibility for, the item being compliant with EU regs. And guess what. You're the importer.

This thing will cheerfully kill you or burn your house down. I wouldn't want to be answering inquiry why I fit this particular thing instead of a listed unit.

It's not an anti-mail-order conspiracy. The conspiracy is Alibaba's, because their stuff is such complete junk and they don't even try to meet safety standards. The Alibaba junkstream feeds AliExpress, eBay and Amazon Marketplace (anything that doesn't say "ships from and sold by amazon.com"). Feel free to buy from, say, Real Amazon.

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