I recently purchased a 50 metre Ethernet cable to run from the modem downstairs to the bedroom upstairs (along the walls as I’m currently in a renting situation), but I can’t straighten the cord to be able to sit flat along the walls.
I’m currently using wall safe double sided type tape that normally works well, but no matter what I try, the cord just comes off the wall due to it being curled.
Any help would be greatly appreciated?
I have attached pictures below of what the cord looks like!
You're uncoiling the cord wrong, and twisting it as a result.
Treat it as a spool. Roll the coil to pull wire off it, don't just pull it off the side. Either roll the coil between the two points, or put a hub/stick through the center and pull the wire straight out in the same plane as the coil, not from the side, letting the coil rotate as you do so.
Spooling is how it was packed, spooling is how it wants to be unpacked. Otherwise you will be twisting it, with the results you've seen.
(Digression into flipcoiling, which would allow pulling it straight out, deferred as tangential. Cable is never sold as flip-coiled; spooling is far cheaper and easier to automate, and isn't a problem if you unpack it properly.)
Addendum: Having made the mistake, you need to either stack it back into a coil and unroll it properly, or twist it umpteen times in the correct direction to flatten it out, working the counter-twist down the cable while trying not to get the part you have un-twisted twisted again in the opposite direction. Easier to demonstrate than describe.
The answer by Keshlam is the correct answer if you didn't unroll it like this, but as you already have (and assuming you can't roll it back):
The goal of the firm grip is to create friction to warm up the cable. The tension of pulling combined with the heat will pull things straight. The goal of the towel folding is not to burn yourself.
Tip: This trick is common practice in (at least) theatres :) This works for most cables, so if you have a laptop adapter cable, or a power cable this works very well too.
You could use cable trunking that attaches to the wall with double-sided tape. These are long plastic conduits that you tape to the wall, put the cable inside, then close with a plastic cover. I used one for an extension cord and it looked nice. The only downside was when I went to remove it to renovate the room, the tape was so strong it pulled off the wall paint with it.
In addition to the towels/screwdriver techniques suggested, sticky screwy mounted cable ties are great for wrangling stubborn cables. The cable and the ties can be pulled tight enough that it stays straight.
Coax cable staples. You get them at big box hardware stores. They look like a little plastic "u" with a nail in one side. Just nail thru the carpet into the subfloor. When you move they'll pull right back up and your landlord will never know.
