Tír Na HiFi

If you ever have issues with bad mains coming into your house you might take the view that there is some validity to decent mains cables. I've certainly heard a difference with mains cables but it's up to individuals to decide if they hear it and if they think its an improvement.

I have to add that years ago when renovating this old house I asked the electrician to put in a separate spur and good earth in the alcove where the hifi would go, also MK sockets with no switches.

A lot of Hifi is eliminating/filtering stuff rather than adding to it.

Mains are all about RF noise rejection, as far as i understood. Few people even said they make most difference, more than IC or speaker cables (for example, Darren, engineer from PS Audio, talks about benefits of power cables in almost every episode in his podcast https://www.thehifipodcast.net/episodes , interesting discussions in general, not just cables).
Just look where those cables are - usually behind the rack, close to adapters, other cables, modems, routers, so many different RF noise emitting devices that they pick up all kind of garbage. Guess that's why they say you first put a good power cable and power conditioners to DAC or other front end electronics, and power amp is the last.
I made my own DIY power cables, but only later found out that a good quality socket connectors are very important, so have to replace my cheap ones with some furutech fancy stuff (70-100€ are just plugs!). The cable is OFC tick twisted wire wrapped into copper shield (each wire), so should be good for RF rejection.

Personally I believe "good" cables will make a small improvement in a proper hifi system that has been already set up in the listening room. But I never wanted to spend much money on them. So I started to assemble them myself following simple projects available on the web (mainly tnt-audio in my case). And since then I have never desired to buy expensive commercial cables. Almost all the cables in my systems are full diy, or lengths of commercial ones terminated by me. In this way I save money that will be invested in expensive hifi amplifiers, speakers,... But that's another story.

Best

Feck the interconnect cables you need to contact ESB directly about the type of cabling they supply to your house.