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WEMO Maker Inventor
Posts: 1,739
Registered: ‎06-14-2014

Re: WeMo Light Switch with two wires?

There may be some confusion over your description.  Connecting the WeMo's neutral line to ground is certainly against code but is a relatively low current.  Your message reads a bit like a suggestion to connect the entire neutral circuit to ground which would indeed be quite dangerous.  There's a long explanation for why but the simple version is that if it was safe there wouldn't be code requirements for 3 conductors where 2 would do just as well. 

Mike
Reliable and secure (Belkin cloud-free) home automation and remote access:
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Posts: 353
Registered: ‎05-04-2015

Re: WeMo Light Switch with two wires?

[ Edited ]

Hi all

 

If the ground is used as a return path rather than a proper neutral wire then should the ground become disconnected from the neutral for some reason at the distribution board then every appliance around the house that has a ground connection will become live. That's why such a procedure is dangerous and why it is against the regulations.

 

Also, using the ground connection in this way will cause an imbalance in the current flowing in the hot and neutral. Therefore if a residual current trip (GFCI) is installed at the distribution board, it will trip as soon as a significant current flows in the ground wire. If a WeMo switch wired in this way does not cause a trip then it's only because it consumes a small current. It is not an indication that all is well.


Regards

Pete

Posts: 311
Registered: ‎03-08-2017

Re: WeMo Light Switch with two wires?

Bingo. No, the WeMo won't kill you when you get crafty with electricity. When you try to change a bulb on the chandelier it's controlling, though, that might well do the trick.
Posts: 353
Registered: ‎05-04-2015

Re: WeMo Light Switch with two wires?

That's right airmandan, and thanks for the Kudo.

 

Whilst on the subject, many have asked why Belkin does not produce a light switch that only requires two wires and no neutral as other manufacturers have "managed to do it". Well, such a switch would need to allow a small current to pass through the light bulb all the time even when it is off in order to keep the switch powered-up. This is no problem with incandescent bulbs but energy saving fluorescents and LEDs tend to give a flash of light every few seconds when a small current is passed through them which is not enough to light them fully. Nobody wants that.

 

There is another more serious issue though. It means that the lightbulb socket cannot be fully isolated from the mains by turning off the light switch. The small current that needs to flow to keep the electronic wall-switch powered-up is enough to deliver a shock from the lightbulb socket even with the switch "off". Not good. Especially if one gets an electric shock coupled with the added enjoyment of falling off a ladder!

 

Whilst unconfirmed by them, I suspect that Belkin does not wish to subject its customers to such dangers and quite rightly so. Hence the need for a proper neutral connection for the WeMo light switch thereby making it absolutely safe.

Regards

Pete


** Always kudo people who help you and mark their reply as the solution if they resolve your problem! **

Posts: 1
Registered: ‎01-08-2019

Re: WeMo Light Switch with two wires?

Hello, 

 

The picture of the wiring you have shown in not compatible with wemo switches. You need a Hot, Neutral and Load Wire to be compaitble with most smart switches. In older houses sometimes there are not enought wires in the junction box to provide the connections the Wemo needs. This post will cover your options and how you can fix it: https://www.onehoursmarthome.com/blog/wemo-light-switch-installation-no-neutral