Editing 2880: Sheet Bend

{{comic
| number    = 2880
| date      = January 12, 2024
| title     = Sheet Bend
| image     = sheet_bend_2x.png
| imagesize = 317x244px
| noexpand  = true
| titletext = A left-handed sheet bend creates a much weaker connection, especially under moderate loads.
}}

==Explanation==
{{incomplete|Created by a SHEET BOND - Seems like there are way too much about the security problems with this connector and less about explaining the comic. People hopefully realize that they should not use a cursed connector suggested in xkcd so maybe remove some of the warnings!. Do NOT delete this tag too soon.}}
This is the seventh installment in the series of [[:Category:Cursed Connectors|Cursed Connectors]] and presents Cursed Connectors #46: The Sheet Bend. At the time of release this was the lowest number used for a cursed connector, with #286: [[2507: USV-C]] being the one with the highest number after those seven comics.

This comic shows two double-core cables being joined in a knot to make an electrical connection. The knot used to tie the two halves of the cable is a {{w|sheet bend}}, which is often used to join two ropes of different thicknesses, and explains the name for this type of cursed connector.

Instead of the join being made a conventional way (either by plug/socket connection, both wires being joined in a junction block or even the matching core-wire ends being twisted or soldered together and the joins covered with insulating tape), the diagram shows that each core is arranged to be connected to a conductive outer sheath, then the wires themselves are tied together such that the just the respective outer sheaths touch and the connection is made between them. A wire with two sequential points of connectivity for different signals is vaguely similar to how a coaxial plug (e.g. a so-called {{w|Phone connector (audio)|'phono'}} plug) has two or more bands of connectivity which make contact with a compatible socket, although that plug-end is rigid, and certainly not flexible enough to be tied into a sheet bend. Nor could one plug end be easily placed up against another such plug end to extend the connection into another length of cable. 

Although a fanciful extreme, the ad-hoc bonding of electrical wiring is a scenario commonly encountered by hobby engineers from the last millenium (the target demographic of the comic), who may have experience in electrical soldering and strong knowledge of how devices interconnect, but would be a red-flag in mainstream systems or professional repair. It is not even an easy solution for handling a broken wire, as extensive prior modification of the ends is necessary. That said, a hand-repaired wire can easily break again, and so hobby repairists can come up with solutions such as the tying the cables together to reduce the strain upon the reconnected elements. The proposed solution seems to suggest a ''planned'' connection method that is meant to satisfy both electrical and mechanical connectivity through knot-work, and can appear quite satisfying with regard to how the knot holds the tension of the cable in a way that actually would strengthen the electrical connection (presumably twisting the contact patches tighter) rather than breaking it.

Historically, tying wire together has been used to connect wires, with one example being the {{w|Western Union splice}}, used to connect telegraph lines. In contrast to the pictured image, this splice was used on a single-strand conductor. The return part of the circuit would consist of a parallel wire, probably with its own splice(s) in it as required.

People who use “repair” jobs like this usually retain awareness and experience to continue learning and repairing as further issues develop.

This is not the way electrical connections are usually made. As those familiar with larger currents are aware, you might get an electric shock or start a fire from touching the conducting surfaces of such wires, unless additional insulation is placed around the knot. If the cable does not carry dangerous currents, it may instead carry low voltage signals (e.g. network traffic), and be susceptible to interference by unwanted electrical currents leaking ''into'' the connection. At best, these can degrade the integrity of the information the cable carries; at worst, the equipment which uses the wire could be damaged by an out of range spike in current.

Most connectors, even those like the relatively exposed {{w|punch-down block}} or {{w|screw terminal block}} types, would use some structural housing (and even {{w|AC power plugs and sockets#Protection from accidental contact|other methods}}) to ensure that the 'live' ends of a socket/plug/hybrid terminator are not touched to other live wires, grounded casings or objects/people, generally according to the relative dangers from, or to, the equipment to which the cable is connected.

The knot is designed to ensure that the connectors that are intended to connect remain in contact, and prevent those from alternate strands from touching, but this guarantee is not that robust. If the knot is not constructed or handled correctly, it could lose connectivity or, worse, short out the circuit, but also the cable could slip loose (perhaps by insufficient tensioning of the knot, from the start) and the exposed conducting sheaths make other improper/dangerous connections across or beyond the knot itself. In both cases, the connection of the 'connector' would be at least become unreliable, even if it only disconnected the intended contact-points due to slippage – whether or not it became mechanically untied.

The title text says that a left handed sheet bend would provide a weaker connection. An actual left handed sheet bend provides less strength to the knot. This makes the title text a pun on the double meaning of "moderate load" (as in a moderate amount of physical tension applied through the cables ''or'' a moderate amount of electrical current passing through them). The difference between a left handed and right handed sheet knot is that the two free ends of the knotted 'cords' are in the same orientation for a right-handed sheet knot (here,  both on the lower side of the image), but on opposite sides for a left-handed sheet knot. When there is more tension drawing two conductive surfaces together, there is less resistance between them, strengthening the electrical connection as well.

Knots was also the subject of the relative recent [[2738: Omniknot]].

==Transcript==
:[Above the drawing there is a header. Below the header there is a double-core wire going in from the left and stopping just past the middle of the picture. It shows how the inside of the wire looks and how the silver and golden wires inside are connected to two rectangular pieces of silver and golden material respectively. The golden piece is to the left and the silver piece to the right, closest to the end of the wire. Beneath this wire is shown two double-core wires forming a knot of the sheet bend type. Here it becomes clear that the silver and golden pieces are on the outside of the wires (but connected to the wires running inside the wires). In the knotted part of the wires gold touches gold and silver touches silver, without them touching the other color. Beneath this knot there is a label for the connector.]
:Cursed Connectors #46:
:The Sheet Bend

{{comic discussion}}

[[Category:Cursed Connectors]]
[[Category:Comics with color]]
@@ Line 10: / Line 10: @@
 ==Explanation==
-This is the seventh installment in the series of [[:Category:Cursed Connectors|Cursed Connectors]] and presents Cursed Connectors #46: The Sheet Bend. At the time of release this was the lowest number used for a cursed connector, replacing [[2495: Universal Seat Belt|#65: Universal Seat Belt]] (with [[2507: USV-C|#280: USV-C]] being the one with the highest number).
+{{incomplete|Created by a SHEET BOND - Seems like there are way too much about the security problems with this connector and less about explaining the comic. People hopefully realize that they should not use a cursed connector suggested in xkcd so maybe remove some of the warnings!. Do NOT delete this tag too soon.}}
+This is the seventh installment in the series of [[:Category:Cursed Connectors|Cursed Connectors]] and presents Cursed Connectors #46: The Sheet Bend. At the time of release this was the lowest number used for a cursed connector, with #286: [[2507: USV-C]] being the one with the highest number after those seven comics.
-This comic shows two double-core cables being joined in a knot to make an electrical connection. The knot used to tie the two halves of the cable is a {{w|sheet bend}}, which is often used to join two ropes of different thicknesses, and explains the name for this type of cursed connector, which seems to be made by ensuring each cable end is terminated with identical electrical connections to the outer sleeving in a manner similar to various 'ring' connections in {{w|Phone connector (audio)|'phone' connectors}}, but as significantly longer and more separated sleeves.
+This comic shows two double-core cables being joined in a knot to make an electrical connection. The knot used to tie the two halves of the cable is a {{w|sheet bend}}, which is often used to join two ropes of different thicknesses, and explains the name for this type of cursed connector.
-In contrast to more normal methods, [[Randall]] has proposed yet another of his 'cursed' connectors. This one requires ''no'' additional plugs, sockets, enclosures or even tools to use. Any two cables with such ends can be brought together and simply knotted together. This particular knot, and the specific spacing of its two external conductors, appears to be chosen in order to rather elegantly create consistent connections between the respective contacts, with a minimum of fuss.
+Instead of the join being made a conventional way (either by plug/socket connection, both wires being joined in a junction block or even the matching core-wire ends being twisted or soldered together and the joins covered with insulating tape), the diagram shows that each core is arranged to be connected to a conductive outer sheath, then the wires themselves are tied together such that the just the respective outer sheaths touch and the connection is made between them. A wire with two sequential points of connectivity for different signals is vaguely similar to how a coaxial plug (e.g. a so-called {{w|Phone connector (audio)|'phono'}} plug) has two or more bands of connectivity which make contact with a compatible socket, although that plug-end is rigid, and certainly not flexible enough to be tied into a sheet bend. Nor could one plug end be easily placed up against another such plug end to extend the connection into another length of cable.
-However, there are potentially many unaddressed but conspicuous problems with this connection method, thus rendering it a 'cursed' connector. Among the issues are:
+Although a fanciful extreme, the ad-hoc bonding of electrical wiring is a scenario commonly encountered by hobby engineers from the last millenium (the target demographic of the comic), who may have experience in electrical soldering and strong knowledge of how devices interconnect, but would be a red-flag in mainstream systems or professional repair. It is not even an easy solution for handling a broken wire, as extensive prior modification of the ends is necessary. That said, a hand-repaired wire can easily break again, and so hobby repairists can come up with solutions such as the tying the cables together to reduce the strain upon the reconnected elements. The proposed solution seems to suggest a ''planned'' connection method that is meant to satisfy both electrical and mechanical connectivity through knot-work, and can appear quite satisfying with regard to how the knot holds the tension of the cable in a way that actually would strengthen the electrical connection (presumably twisting the contact patches tighter) rather than breaking it.
-* The need to have suitable ends to any cables, which would involve issues in the manufacture (and the materials used) as cable's cores must be separately tapped and reliably connected to an external length of conductive sleeving.
-* The consistent ability of a cabler to tie the correct knot, which is a skill that will need practice. Done wrongly the electrical connections may not be made correctly, or at all (including as discussed in the title text).
-* Even if initially tied correctly, knots can slip or distort when subsequently pulled more taut.
-* Even if the user is a competent and consistent knot-tier, this is inherently more effort, and therefore less convenient, than the more usual practice of simply pushing two connectors together.
-* The external conducting patches of the cable are an uncommon feature of electrical junctions, with issues in both high-power and low-power situations.
-** If the cables are supposed to carry high voltages, any bare conductors ought to be safely isolated from easy contact with equipment/people. In particular, plugs and sockets that carry anything approaching mains-voltages have active and passive elements integrated which protect the person connecting or disconnecting the equipment. There is no physical precaution visible to protect the person tying or untying the cable from potential shock. Instead, they must rely upon the ''other'' end of the potentially 'live' cable being disconnected. And, when left unattended, there would continue to be a high risk of injury (including death), fire or more basic damage due to the lack of any proper physical isolation.
-** Low-voltage cables that pass signals between equipment (e.g. networking data or audio signals) are susceptible to external contact disrupting the flow. Random static charges, built up and transfered into the connector, instead make other equipment or people the potential threat to the cabled-up equipment, causing disruption to the normal purpose of the cable, where a more standard plug-and-socket/hard-wired connection would not.
-* The bending, twisting and rubbing of the cables each time the cables are connected and disconnected will very likely cause wear and damage over time.
-* The knot provides a possible snag point by which the cable could be caught; anything which catches or tugs on the knot could cause disconnection.
-The title text says that a left-handed sheet bend would provide a weaker connection. The difference between a left-handed and right-handed sheet knot is that the two free ends of the knotted 'cords' are in the same orientation for a right-handed sheet knot (here, both on the lower side of the image), but on opposite sides for a left-handed sheet knot. A left-handed sheet bend provides less strength to the knot, due to the possibility of distorting (e.g. {{w|Knot#Capsizing|''capsizing''}}) and/or allowing one or both cables to pull through the knot.
+Historically, tying wire together has been used to connect wires, with one example being the {{w|Western Union splice}}, used to connect telegraph lines. In contrast to the pictured image, this splice was used on a single-strand conductor. The return part of the circuit would consist of a parallel wire, probably with its own splice(s) in it as required.
-This makes the title text a pun on the double meaning of "moderate load", which could be a moderate amount of physical tension applied through the cables ''or'' a moderate amount of electrical current passing through them. Together, it would be expected that tension drawing two conductive surfaces together would create less resistance between them, strengthening the electrical connection as well, but only if the knot holds as expected.
+People who use “repair” jobs like this usually retain awareness and experience to continue learning and repairing as further issues develop.
-A knot was also the subject of the relatively recent [[2738: Omniknot]].
+This is not the way electrical connections are usually made. As those familiar with larger currents are aware, you might get an electric shock or start a fire from touching the conducting surfaces of such wires, unless additional insulation is placed around the knot. If the cable does not carry dangerous currents, it may instead carry low voltage signals (e.g. network traffic), and be susceptible to interference by unwanted electrical currents leaking ''into'' the connection. At best, these can degrade the integrity of the information the cable carries; at worst, the equipment which uses the wire could be damaged by an out of range spike in current.
+Most connectors, even those like the relatively exposed {{w|punch-down block}} or {{w|screw terminal block}} types, would use some structural housing (and even {{w|AC power plugs and sockets#Protection from accidental contact|other methods}}) to ensure that the 'live' ends of a socket/plug/hybrid terminator are not touched to other live wires, grounded casings or objects/people, generally according to the relative dangers from, or to, the equipment to which the cable is connected.
+The knot is designed to ensure that the connectors that are intended to connect remain in contact, and prevent those from alternate strands from touching, but this guarantee is not that robust. If the knot is not constructed or handled correctly, it could lose connectivity or, worse, short out the circuit, but also the cable could slip loose (perhaps by insufficient tensioning of the knot, from the start) and the exposed conducting sheaths make other improper/dangerous connections across or beyond the knot itself. In both cases, the connection of the 'connector' would be at least become unreliable, even if it only disconnected the intended contact-points due to slippage – whether or not it became mechanically untied.
+The title text says that a left handed sheet bend would provide a weaker connection. An actual left handed sheet bend provides less strength to the knot. This makes the title text a pun on the double meaning of "moderate load" (as in a moderate amount of physical tension applied through the cables ''or'' a moderate amount of electrical current passing through them). The difference between a left handed and right handed sheet knot is that the two free ends of the knotted 'cords' are in the same orientation for a right-handed sheet knot (here,  both on the lower side of the image), but on opposite sides for a left-handed sheet knot. When there is more tension drawing two conductive surfaces together, there is less resistance between them, strengthening the electrical connection as well.
+Knots was also the subject of the relative recent [[2738: Omniknot]].
 ==Transcript==