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I have a rope of 10 m which supports 3 kN (300 kg) strength. I will abseil with it as a single rope.

I want to know what is the recommended knot to use when attaching the top with my anchor's carabiner?

The specific rope in question is an uncertified 10mm kern-mantel accessory cord from a company called XINDA.

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    I wonder if you know enough about abseiling to use that knot you are asking about. Better get instructions of someone out in the field, learn ropes (knots and tools) from them before setting out alone. – Willeke May 28 '18 at 16:00
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    Honestly, if you have to ask safety critical questions like this online (especially with an obviously unsuitable rope), you shouldn't be doing the things you're asking about. – Qudit May 28 '18 at 19:37
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    They are even honest enough to not fake certification, which still means don't trust it for anything safety relevant. – imsodin May 29 '18 at 9:02
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    A fall of a very short distance on a small amount of rope would EASILY exceed 3kn. This "rope" is incredibly dangerous to abseil on. – user2766 May 29 '18 at 13:32
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    @ShemSeger Sure, but that's simply not relevant. I have also done plenty stuff that I would do again under the particular situation I was in, but that was was dangerous and not recommendable. – imsodin May 29 '18 at 21:06
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Safety disclaimer first

I have a rope of 10 m which supports 3 kN (300 kg) strength. I will abseil with it as a single rope.

Edit addressing the new info about the rope:
Please don't use this rope for abseiling. It is not certified and it is marketed with a random selection of catch-words, no actual information about it properties except the diameter and supposed strength (which is useless in the absence of a specified procedure of how they arrived at that number).

Old disclaimer without specifics as the rope (still true, but more general):
I assume it is a static ("low-stretch") rope. With 3kN it is hardly a climbing rope (EN1891) - I am only aware of cords rated at such a low strength. If it is rated after intended load as often done in "industry" compared to peak/breaking load in climbing that aspect would be fine. If it is rated by max/peak/breaking load, then 300kN is not enough. The knot will further decrease this, meaning you won't have enough safety margin. In any case the question still remains: Is such a rope suited for the abseil you are setting up (rock contact)?

Actual answer to which knot to use

That being said the goto knot around here is a figure of eight. One reason is the same as for it's use to connect your harness to the rope: It is simple and easy to control. It also means, you don't need to introduce a new knot to a beginner. And it is reasonably simple to undo.
There's also the aspect of decreased strength of the rope when knotting it. That's not an issue with "normal" climbing ropes. Even the worst knot in that aspect won't bring the strength so far down, that it gets problematic. In general the smaller the radii in a knot, the more strength reduction (so bowline is better than eight better than overhand, all on bight). This is a gross over-simplification, knots are extremely complex and this won't hold true in all cases, it's just a rule of thumb. And again, simplicity to tie, inspect and untie are more important (that's why bowline isn't used for this around here - nothing wrong with using that though).

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    It sounds like this is either thin climbing cord or a hardware store rope. Either way, in addition to strength issues, the rope's diameter may not be within the required range for the rappel device, so it may not brake properly. – Qudit May 28 '18 at 19:26
  • "bowline is better than eight better than overhand" Actually, according to Freedom of the Hills (9th edition, p155), a figure eight on a bight reduces strength by 23-34% while a bowline reduces it by 26-45% so the figure eight is stronger on average. – Qudit May 28 '18 at 19:35
  • @Qudit Is the bowline also on a bight/double? I definitely meant all of the three in the same "configuration", otherwise one is comparing apples to oranges. Well actually, a single bowline could be used here, but that knot is outlawed for climbing around here, so I don't even consider it ever. – imsodin May 28 '18 at 20:32
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    Let us continue this discussion in chat. – Qudit May 28 '18 at 21:33
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    @user1780468 I wouldn't use that rope. It might be fine to use, but it is not certified. So unless you know exactly what this rope is, don't use it. And your questions make it clear, that you do not have that in-depth knowledge - no offense intended, neither do I, this is your and any other user's life that is at stake here. – imsodin May 29 '18 at 8:54

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