I have a 500W 24V power supply for running 24V LED strips. The power supply says it's rated for ~21 amps (500W / 24V). Assume input is US 120V household power.
I want to control the 120V supply with a relay driven by 5V Arduino logic signal.
I'll be driving 4x 24V 96W LED strips.
From A = W / V:
A = (4 * 96W) / 24V = 16
Does this mean I need a relay rated for 16 Amps or 21 amps listed on the power supply specs?
Do I work back to Watts from the relay's specs?
Example relay is rated at 5A / 220V AC:
W = 5A * 220V = 1100
Though I've read choosing a 16A or above relay is a good idea since it shouldn't be the first thing that fails in a power surge.
More info: Here's the power supply I have: https://www.amazon.com/gp/product/B01IU8QBCO/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1
And will be purchasing one of these for 12V landscape lighting: https://www.amazon.com/gp/product/B06XR3ZLSG/ref=ox_sc_saved_title_8?smid=A3S4SVMWTDK1H2&psc=1
Looking at a relay like this to be on the safe side: https://www.amazon.com/AC100V-250V-2-Channel-High-low-Trigger-Arduino/dp/B077W1NVLM/ref=pd_ybh_a_15?_encoding=UTF8&psc=1&refRID=RAE8FR66XX0GN9YQANXR
EDIT: Suggested alternative: Though I'm confident wiring mains I like to avoid it. I'd suggest anyone not confident to go buy one of these (I'll be getting one for my project): https://www.adafruit.com/product/2935