I am trying to power 15 meters of 5V LEDs. I got a hold of this power supply which gives 5V and 20A DC. It should do the job, I'm just not sure how to hook it up. The connections are L, N, ground symbol, com, com, +V, +V. I included a picture. How do I go from my outlet to the power supply and then to the LED strip?
It also says to select 110V or 220V on the switch, I believe 110 should be fine even though the house rms voltage is 120, not a problem right?
L, N and ground are Line (hot) Neutral and ground for a standard 3 wire plug (note that in house wiring, black is the hot wire, white is the neutral and green or bare is ground. The com and com should be the same (both negative DC) and the two +5 should be the same for the +5 power. As far as 110 vs 120, for this exercise, they are the same. The "com" goes to the negative side of the LED strip and the +5 goes to the positive side. You indicated they were "5V leds" - is that how they are spec'd? Normally LED's require a current limit resistor, but if these say they are 5v then they may already have the current limit built in.
They are spec'd at 5V and 6.4W per meter. It's an individually addressable strip that the arduino will control. I assume they will just draw as much current as they need at 5 volts.
I should be all set, think you pretty much answered all my questions. One last thing though, to get L N and G, can I just strip off an old laptop charger before the transformer and just hook that up? Also what happens if I'm missing ground (2 prongs only)?
That is a metal encased power supply which is not double insulated and therefore may only be used with the earth or ground connection made. To operate without an earth connection seriously exposes the user to potentially fatal voltages if and when the unit develops a fault
Yeah, what he said 
Ok I will be sure to connect ground. Thanks everyone
I should have said that "black is hot, white neutral and green or bare is ground" in house wiring in the US. Other parts of the world seem to have a different standard (although I dang near got myself fried some years ago hooking up a tape drive to a system at work. Hooked the data cable up to the system and the tape drive, then made sure power was off on the tape drive and plugged in the standard new line cord that came with it. FLASH!! System crashed, circuit breaker tripped (and it blew the CPU card on our server). Seems the brand new line cord (with all the correct UL, CSA etc. approval stamps on it) had the male hot prong on the plug wired to the female ground pin on the other end of the molded cord. Got Boeing Safety involved in that one (scared me just a bit - I was alone in the computer room at 3am doing month end backups!!) Fortunately, I had hooked the data cable up so when I plugged the power cord in, the grounds in the data cable shorted the power to ground and blowing breakers and the cpu card in the server and not me!! :o