Cable extension recommendation

[Greatestfoe]

Hi. I was looking to get some extensions for my 8 pin eps cable , 24pin Cable, and maybe for the 8 pin pci e cable (2 of them actually). I read something awhile back about someone using old cables on a new psu and it basically fried their system, the wire layout was different and a few reviews for extensions say stuff like that too. 
 

I was wondering if anyone could recommend some decent extensions, preferably sleeved or if having the wrong extension could fry my system. There's really no information about this (that I can find) and specs don't say anything either. I don't know if it matters but I'm using an evga 850 g3 supernova psu and a evga z370 ftw motherboard, I also contacted their support but they didn't really help besides pointing out that they sell some L shaped pcie cable extension thing. 
 

thanks for your time. 

[Ankerson]

It's best to buy a full cable kit, less points of failure and issues.

 

https://cablemod.com/products/?filter_series=e-series

 

Or from EVGA:

 

https://www.evga.com/products/productlist.aspx?type=10&family=Power+Supplies&chipset=Power+Supply+Cable+Set+(Individually+Sleeved)

[Mick Naughty]

I just got a set from amazon. Same stuff I seen on eBay. 
Worth the price as I’m not gonna make custom cables or de pin all of mine and sleeve them right now. So buying these is the only choice. 
I’m sure all the other ones offered would work all the same. 
 

https://www.amazon.com/gp/aw/d/B07VPB9LR3?psc=1&ref=ppx_pop_mob_b_asin_title

[Pixie La Luna]

I would go with a full set. The last thing you want to do is ruin a build cause of $30 or so. 
I got these ones off Amazon and they were nice to work with, and have been doing great so far (1 week lol).
https://www.amazon.com/gp/product/B07C735N9C/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

 

They're not as firm as I wanted, but they go around corners well without kinking, and come with clear and black cable combs (in the white set I got).
You can see them in the pic of my latest build. I did struggle a little with getting them stay "square" so to speak, but I'm very happy with them.

And here is the video of me installing them, I've started it at the 13:43 mark where I talk about them