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NCaliZen t1_j2nscst wrote

The issue with LED fixtures is that they can have a significant amount of inrush - current that comes through the device when it is initially turned on. That inrush can destroy your control device.

(Note: This isn’t the first time something like this happened in the industry. When the industry moved from magnetic ballasts to electronic ballasts for fluorescent lamps, the new ballasts had a significantly higher inrush. A side effect was some manufacturer’s wall switch devices couldn’t handle the inrush and would be destroyed. The National Electrical Manufacturer’s Association (NEMA) worked on a standard to define an acceptable amount of inrush, but by the time the NEMA 410 inrush standard was developed, electronic ballast manufacturers had mostly redesigned their product to reduce inrush. History just repeated itself with the introduction of LED lighting.)

If you had a dimmer that didn’t call out a LED rating, the safest thing to do would be to divide it’s rating by 10, so a 600W dimmer shouldn’t control more than 60W of LEDs.

However, since the dimmer you have calls out a 150W LED rating, you should be fine loading it with - in your given example - 84W.

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argon561 t1_j2nzb61 wrote

It's correct that the inrush current is the MAIN problem with LED lighting.. Though it should be noted that most dimmers now actually circumvents this problem by trickle charging the LED-driver capacitors, and by doing this, can absolutely handle the continuous wattage specification.

It's quite easy to check if you have such a dimmer (or LED-driver for that matter).

Turn the lights off. Let them stay off a couple of seconds.

Turn them on. If they don't respond IMMEDEATELY when the button on the dimmer is clicked (like they do when shut off), the dimmer is "trickle charging" the capacitors with it's own circuitry. When the inrush current goes below a threshold that is acceptable, the lights will turn on and "full power" is fed to the lights.

This can also be noticed if a LED "gradually gets bright", and not "direct full brightness" when it's switched on.

If it's a very old control device / dimmer, it might not have this feature, and on those, you'd be best of by dividing it's rating by at least 10.

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