Is it possible to use a wall AC 20A dedicated circuit for my desktop?
Is it possible to use a wall AC 20A dedicated circuit for my desktop?
I own a wall AC that isn’t needed anymore and is connected to a 20A circuit outlet, which has a 20A-125V receptacle. It seems this circuit is dedicated. I’m considering using it for my desktop or PC accessories like monitors and speakers. I’ve noticed the ceiling light flickers slightly when I start my PC. My desktop uses a Cosair RM750x PSU that draws 10A. My worry is that if the current exceeds 10A, the PSU could be damaged before the breaker trips. Another idea is to plug my peripherals into this 20A circuit using a power strip. I think the power strip isn’t rated for 20A because its contact openings aren’t t-shaped. Which option is safer or which one might cause problems?
It's a bit tricky to see, but I think the outlet is a typical 20A socket that can fit a standard 15A device. To confirm if it's a dedicated circuit, check your breaker box for a 20A breaker possibly marked for the room. This setup likely came from when you installed a window air conditioner.
You're correct about the installation. It seems the breaker box lacks specific labeling, but it likely has a dedicated circuit for a wall AC. Connecting your PSU or power strip to it would depend on the safety of that dedicated circuit. It's best to confirm with a professional before proceeding.
When I was setting up the main wiring for high-power radio systems in buildings, I selected the circuit breaker capacity to safeguard the wiring leading to the wall outlet, not the equipment itself, which received its own distinct protection (usually a lower-rated fuse). Generally, most 20A breakers won’t activate until a steady current of about twice or more reaches the circuit—meaning 40A for a 20A breaker. The same applies to fuses; they won’t trip until double the rated current flows through them. The 10A rating mentioned in the specifications for the RM750X refers to the maximum continuous current the power supply can draw from a standard 115V, 60Hz AC source to deliver its full 750W output. In reality, the RM750X would likely not reach 10A continuously unless the voltage fell below 85V AC while the computer consumed 750W. Applying simple calculations, 85V multiplied by 10A equals 850W. Subtracting the 750W maximum output leaves only 100W of inefficiency. This suggests the PSU would operate safely well under its minimum rated 100V. Under normal operation, the RM750X will draw far less than 10A continuously, since the power supply provides less than 750W. It only draws what it needs from the wall outlet at any given moment—perhaps 150W or 250W or even less. The flickering of ceiling lights when the PSU powers on is due to a brief surge: the RM750X (2021 model) temporarily draws 24.930A from a 115V AC source (or 51.640A from a 230V AC source) at startup. This spike charges the bulk capacitor in the PSU and causes a short-term voltage drop in the mains, which can affect nearby light bulbs. For more details on this issue, see the review for the RM750x 2021 model [here]( In my area, wall outlets are supplied from a "ring main" protected by a 30A breaker. The voltage in my country is approximately 230V AC (50Hz), not 115V 60Hz. I’m comfortable using a 20A feed for my computer, as my wall circuit breakers are rated at 30A, provided you add extra protection for the IEC mains cord—such as a fused adapter strip connected to the wall. In other countries, mains plugs in cords have built-in fuses ranging from 2A to 13A. You should choose a fuse in the plug that matches the cord’s rating and protect the cable between the wall and your equipment. Most ATX power supplies include an internal fuse designed to blow during severe overloads. If you’re unsure, it’s wise to consult a qualified electrician. Avoid handling AC mains—safety is crucial.