Why is neutral wiring in a home automation system necessary/best to install?

[u587162]

Why is it best to use/install neutral wiring for swatches in a home automation design? How big should the back boxes be to accommodate z-wave relay switches behind the switch?

 

[theprinceofdarkness]

Look at the user manual linked to from this site :- http://www.monoprice.com/product?p_id=11990 Basically the box its self need a mains supply ( L&N).
Frank

 

[dpm_dpmartin]

As said, if you want control of lighting from the switch, dimming or just on / off, you need to provide power to the Z-wave device itself, so it can switch power to the lighting. My house wiring wasn't suitable, so I'm limited to lamps and things like blinds, plus various sensors.

 

[u587162]

As said, if you want control of lighting from the switch, dimming or just on / off, you need to provide power to the Z-wave device itself, so it can switch power to the lighting. My house wiring wasn't suitable, so I'm limited to lamps and things like blinds, plus various sensors.

I get that the z wave device needs power (what device doesn't) but it's the requirement for neutral cabling I'm not getting. You can still control a z wave device without neutral.

 

[bernardgreen]

You can still control a z wave device without neutral.

Control without Neutral YES, provide POWER without Neutral NO

 

[u587162]

Sorry pls explain in layman terms - how can you provide control to something without power?

I think I can have a wireless z wave relay switch fitted behind a socket which provides power to a blind. I will be able to control it via my iPhone.

 

[bernardgreen]

You send the control signal by wireless, no wires. But to receive and respond to the control signal the receiver has to have power, either from a battery or from the mains supply. If it is from the mains supply then it has to have the Live and the Neutral. Some devices get their Neutral via the lamp they are controlling when that lamp is OFF but this requires a small amount of current to be flowing through the lamp when it is OFF. For incandescent lamps this small current has no effect. But for energy saving and some LED lamps this very low current does have a noticable effect. Some CFLs will flash when OFF and some LED lamps will either flash or glow dimly when OFF. And when the lamps is ON it is not fully on as a small volatage has to be taken by the receiver as power to receive and respond to further control signals.