So you just unboxed your
shiny, brand new, state-of-the-art Wi-Fi smart switch and you can't
wait to install it! You've turned off your main breaker, removed your
old, analog light switch and have pulled out the old switch revealing
the wires within the wall box. You can clearly see the hot (line) and
the load wire leading up to your ceiling fixture, but there is one
crucial component missing that your instruction manual for your smart
switch is asking for: a neutral wire.
If you have a similar setup to
what is described here in your older house which predates smart
switches, then what you have is likely a switch loop where the
electricians simply ran the hot wire to the switch box, completed the
circuit at the box, and did not run a neutral wire to the switch
itself leaving you with the neutral only up at the ceiling fixture.
Before you start tearing out all of your dry wall in frustration,
rest assured, you have come to the right place!
Here's the exact scientific
explanation as to why your smart switch needs a neutral and the 3
engineering approved ways to go smart with your lights:
1.
Physics of a smart switch(Why it needs a neutral)
The mechanical light switch of
old was really nothing more than a simple bridge; either connected,
to complete the electrical circuit, or separated to break it. Flip it
on and the bridge completes the circuit from the hot wire to the load
wire to the light bulb; flip it off, the bridge is broken and the
light bulb is off.
However your smart switch is
quite a bit more complex than a mere bridge. It is a small computer
which has within it, a microcontroller, a miniature relay, and a
wireless transceiver( Wi-Fi, Zigbee, Z-wave). This small computer has
to be powered 24/7 to maintain connection to the network and to
listen for your commands even when the light bulb is off. To maintain
power, your smart switch needs a circuit which it can power itself
from: from the hot wire to the neutral wire. If you do not have a
neutral wire, then the smart switch cannot power itself.
2.
Solution A-No neutral smart switch(Trickle Charge)
Engineers at the smart switch
companies quickly realized this was going to be a huge hurdle to
overcome with the adoption of smart switches in older houses, so they
found a rather clever solution; a No Neutral smart switch. The
designer circumvents the issue of not having a neutral by allowing a
tiny amount of electricity, carefully regulated, to trickle charge
through the load wire up to the light bulb and back down the neutral
in the ceiling.
Side
effect: Extremely sensitive, low-wattage LED lights may
flicker or dimly glow even though the smart switch has been turned
off because you are always sending a tiny bit of power to the light
bulb.
Fix:
Luckily, almost all reputable no neutral smart switches come with a
tiny capacitor you must wire up in the ceiling fixture in parallel to
the light bulb. This bypass capacitor draws the trickle charge so the
LED light will not flicker when switched off.
3.
Solution B- Smart protocol switches( Forget Wi-Fi)
It's important to note that
most no neutral switches do not make use of standard Wi-Fi; this is
because Wi-Fi uses a lot of power. Trying to power a Wi-Fi radio with
the trickle charge going through the light bulb will most likely
cause a huge amount of flickering and overheating! What you're going
to want to look for is a smart switch that uses a Zigbee, Z-Wave,
or Thread/Matter wireless protocol.
These wireless protocols are
designed to use very small amounts of power so that the trickle
charge is not significant to the operation of your lights and will
not damage them. You will however need a Smart Hub that connects to
your router to communicate with these protocol switches but Zigbee,
Z-Wave, and Thread/Matter controlled devices have far more stable and
safer control.
4.
Solution C-Smart Bulb and wireless remote workaround
For the safest and most simple
solution that will keep you from having to splice your load and hot
together or use bypass capacitors, try this simpler workaround:
1.Turn off the breaker.
2.
Inside the wall box, use a wire nut to
permanently connect the Live wire and the Load wire together. This
means the ceiling light socket now has permanent 24/7 power.
3. Screw a Smart LED light
bulb in to the socket in the ceiling fixture.
4. You can then simply place a
blank face plate over the old switch hole in the wall and stick your
battery powered remote switch or kinetic button to it.
What you've done here is
essentially replaced the mechanical switch with a smart bulb and a
remote. Your smart bulb will be powered on 24/7 and always
communicating with your smart home system and your smart remote
button will be sending the commands to your bulb when you push the
button.
You can still make your house
a smart house and still take advantage of all of the cool features
you were promised by a smart switch company even though you are
unable to run a neutral wire from the ceiling to the wall box without
having to tear down your drywall or call an electrician. By simply
using a trick or the alternative methods that will be presented, you
can make your house smart!
