Need guidance powering LED strips and using a dimmer

[ditzy]

Hello. I want to use LED strips to light a room. I picked out a power supply that can handle the full strip, but this time I want to try out a dimmer. This is some territory I'm not certain of and could use some help, even if it's just guidance at reading materials to help me learn what I need to know.

I'm somewhat new to EE. Haven't done many projects, but I have been using some LED strips for a lot of months now to light part of a room. I'm using 14/2 romex to deliver power from a wall socket through a switch to another wall socket near the light, which is powered by a 12V 6A adapter. It's been working pretty nicely and I'd now like to expand. I'm hoping for a bit of guidance, validation, and/or tempering.

My current plan is to use this 5630 SMD LED strip with this 12V 10A 120W power supply and I was thinking about putting this 12v 8A PWM dimmer on the LED strip. I'm actually re-thinking the 5630 LEDs right now, as I just felt the 5050 LED strip I'm currently using and it's a bit warm, and the 5630 should consume much more power. So that's one concern. But I have 2 other concerns that prompted me to come here.

The first is if that dimmer would work with that power supply. I don't know enough about power supplies, let alone switch mode power supplies, so I don't know if a PWM dimmer might freak it out, or have some kind of interference with the switching of the power supply and have undesirable results. Part of why I am concerned about this is that I've seen specific dimmable power supplies for LED strips, and don't really know what's different about them.

My second concern is about routing power to the various strips if I don't have them right next to each other. I'm not entirely clear on what gauge wire to use if I'm going to route it around a room. I could always just go extreme and use 14 AWG for the whole thing, maybe even full romex. But I don't know if that's overkill. Overkill is safe, but knowing what reasonable safe choices look like would be nice. For most of the last few months I've been using 22 AWG stranded wire to power my current strip and that's been working (the 22 AWG stuff is between the 12V adapter and the strip only, the connections between the adapter and the wall are 14/2 romex). But I'm only using 2 meters of the strip, which should be within the 22 AWG's capabilities I think? I just switched a few days ago to these 2.1mm DC pigtails to power 8ft of my current strip and my multi-meter said it was drawing 1.3A @ 12V. Due to my newness to a lot of this, that worries me a bit, but reviews of those pigtails claimed people were using them at up to 2A. I'd like to stay away from that much current until I have more confidence they can handle it, but even 1.3A is a bit scary.

Can anyone give me any guidance or reassurance about these things? Or let me know if I should stop some of this stuff immediately because I'm doing something dangerously wrong?

Any help is greatly appreciated. Thank you!

 

[MikeHalloran]

Just make sure you have the proper fuses in appropriate places.

TANGENTIALLY,
I bought four 2x2 drop-in 120VAC LED troffers from HD, right before HD stopped selling them.
Each has two Cree LED arrays within.
I wired them radially from the switch with 14/2+gnd, long armored pigtails, so I could move them around in the suspended ceiling without rewiring.
Sure enough, I got to rearrange them once.

SWMBO's second request was for a dimmer, because they are BRIGHT.
They are way way brighter than the 7 x 40 watt fixtures they replaced.
Regular dimmers, all of them, fancy or simple, just went from OFF to FLASHING.
They just don't work with a line dimmer, even if it's marked as appropriate for LED lamps.
Turns out the fixtures have an extra pair of terminals, for gray and purple wires, that are intended to get a 0..10VDC brightness signal in a commercial installation. I have not found the appropriate dimmers in actual inventory and for sale, anywhere. Plenty are listed, at extortionate prices, but nobody has them in stock, except for some multi-component remote controls that are obscenely priced.
So we have learned to live with lots of light in the kitchen.
There are worse things.



Mike Halloran
Pembroke Pines, FL, USA

 

[LionelHutz]

Well, first off romex is for permanently installed wiring. Saying you're taking it from a wall socket sounds like you're running it around the room with a plug on the end, and if so then you should be using some kind of lamp cord or SOOW wire instead.

As for the low voltage wiring - just go by current and distance. You can find MANY sources of wire resistance per length online and anyone who followed the guidelines for posting here must know how to apply Ohms law to calculate the voltage drop.



Mike - superbrightleds has 0-10V dimmers on their site reasonably priced. Says nothing about out of stock.