PSU:What you need to know about single rail and multiple-rail PSU safety

We take safety very seriously when it comes to our products. This article will detail what you need to know about staying safe when dealing with single rail or multiple-rail power supply units.

• What do "single rail" and "multiple-rail" mean?
• What are the differences between the PSU types?
• Is there such a thing as too much amperage?

What do "single rail" and "multiple-rail" mean?

When a PSU is described as "single rail," all of the PSU's power is available from a single source.

When a PSU is described as "multiple-rail," the PSU divides the total available amperage across two or more "rails."

What are the differences between the PSU types?

Single rail PSUs can be more convenient if you have a high performance PC, as you do not need to worry about balancing the power load across multiple rails. All you need to do is check if your PSU meets your system's total power requirements.

In terms of safety, there is no effective difference between the two types of PSUs. While some claim that higher amperage delivered across a single rail introduces risks not found in multiple-rail PSUs with lower amperage, this is not true, as we will explain below.

Is there such a thing as too much amperage?

Some people wonder if having a single rail that delivers more amperage is less safe than having multiple rails that each deliver a smaller amount of amperage. The answer is no, because single-rail PSUs have the same protective circuitry that multiple-rail PSUs do.

When looking at the total amperage, remember that a when a PSU is installed into a PC, the current is spread across multiple cables. You have cables going to your motherboard, your peripherals, your GPU, and more. Because a multiple-rail PSU is not able to draw as much power across a single rail, the multiple-rail design may be safer for your connected components.

This means you will never have a situation where the total amperage is being drawn across a single power cable. Additionally, PSU power cables provided by any reputable PSU manufacturer do not have the impedance that would cause the cable to overload.

In short, when it comes to choosing between a single rail or multiple-rail PSU, safety is not a significant differentiator.