Do I need an isolation transformer?

Question

I am building a 5V circuit where the maximum current draw I expect will be 5-5.5A, so have purchased a 5V 6A power supply IRM-30-5ST.

In order to connect this power supply to the mains, I have purchased a mains plug to IEC female power plug along with an IEC male socket with a 250V 10A fuse. I then plan to connect the L and N terminals of the IEC socket to the L and N input terminals on the power supply with 18AWG wires.

Now I have two questions:

1. Does my power supply have an internal isolation transformer? I have tried searching to see if all Class II power supplies include an isolation transformer, but can't seem to find an answer to this question. There is this post here which seems to imply they do. I have also looked at the datasheet and more information parts from the power supply link above but can't seem to tell if it provides isolation or not for the output.

2. Even if my power supply does isolate the circuit connected to the output, that still means that the 18AWG wires between the IEC socket and my power supply have high voltage, so touching one of these wires or terminals would be very dangerous. If I put my final complete circuitry inside an enclosure and connect the enclosure to the E terminal on my IEC socket, would this make it safe?

My assumption is it would, because the enclosure prevents touching the 18AWG wires between the IEC socket and the power supply, and if one of these wires frays or becomes loose and touches the enclosure, the connection between the enclosure and earth should prevent a shock. Is my assumption wrong?

Outside of the enclosure though, would an isolation transformer connected to mains and then my IEC plug connected to that protect me from shocks if I touch the 18AWG wires? Would I need this isolation transformer if my 18AWG wires are hidden inside an enclosure where the enclosure is connected to earth?

If I do/should be using an isolation transformer (at least when it's outside of an enclosure aka while I'm building it,) would I be better off getting a power supply like this over the power supply I currently have as that power supply looks like it is inherently safer as there is no exposed high voltage wires (main reason I got the power supply I have is because it was the only 5V power supply my local store had.)

Answer 1

The entire question is under the scope of IEC 62368-1.

To the 1st question:

It's indicated in the datasheet that the device is an IEC Class II device which means a device having a "double" insulation. Double insulation requires that the device should withstand at least 3 kVac across its input and output, and the datasheet indicates that the withstand voltage is 4 kVac.

To the 2nd question:

By placing the power supply and the circuitry supplied from it into a metal enclosure and ground the enclosure by bonding the PE cable, you make the entire system Class I, which means a basic insulation as well as safety ground.

In either case, you don't need an extra isolation transformer provided that the end-user will never have a chance to access the live voltage "inside" or "around" the product during normal use.