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I have 4x 55W florescent tubes in my garage, two per fitting. Its dark in there, the garage door opener has a uselessly tiny light.

So the plan is to fit an omnidirectional ceiling motion sensor.

Here's what's in the paperwork:

From docs

Does this mean the sensor switches the Active line while the Neutral line is simply straight through? IE

enter image description here

Does that fill in the missing details correctly ?

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Yes the always hot and neutral are used by the sensor but your lights tie to the neutral then the red wire from the sensor goes to the hot wire for the lights.

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The instructions say "after switch", so that's that. The switch may have functions which require this. Also, you have to obey the labeling and instructions, because the UL listing (or comparable; CE isn't) is only good for labeled uses.

Some motion sensors need power 24x7 to function reliably. That is because they need to "remember" the quiescent state of the room, and the ambient light levels that occur in normal light cycles in this location. If you have a motion sensor that seems to bungle either of those things, try leaving its power on, an see if it adjusts after 48 hours.

  • For a refit sensor like this, that would require moving the power feed from the switch, then running a down-and-up cable back down the wall to the switch - seems a lot of work. Also the diagram above says "240V mains supply via switch" – Criggie May 2 at 20:38
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    @Criggie Good point. Since the labeling and instructions say "after switch" that's what you must do. (NEC 110.3b). Perhaps the unit's builders up-spent for NVRAM to store that data. Most don't. – Harper May 2 at 20:59
  • Most sensors I see in NZ are not that smart, and this is often the intended way to wire them. We place less importance on manufacturers' instructions than you. – Someone Somewhere May 4 at 11:25
  • @SomeoneSomewhere That's not a NZ trait, that's an "everyone who isn't a Code geek" trait :) – Harper May 4 at 13:33
  • I have several motion sensors that need the switch before the light as this or the breaker is the only way to reset them if they lock on from power bumps or surges etc, in fact a double bump of the switch locks them on so it depends on the model and the OP did not give that info. – Ed Beal May 4 at 14:45

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