Can I use electrical tape instead of insulation tubes to insulate a wire? (like in the photo)
Yes. Heat shrink is more durable and will last longer, but a well done tape job is fine.
Treat yourself, buy different sizes of heat shrink.
I'm saying "No"!
This PVC tape commonly sold as "electrical tape" has relatively poor adhesion which fails over time.
And I would certainly not tape it like that image.
If you must, fold the twist down against the cable, wrap it with at least four layers of the tape, then use a Zip tie to hold the wrap tight in the long term. I actually keep Zip ties that have been cur off things and have just an inch or so of length left just for such "small "jobs.
Try a linesman's splice ( Western Union splice - Wikipedia ) before the soldering. It's stronger with a better connection, and you don't have a barb sticking out to tape/heat shrink around.
If you do use electrical tape, try cutting it with a knife or scissors instead of just pulling it until it breaks. When you pull it the tape stretches and if just wrapped around the splice again it will start to shrink back to its original length.
Which is arguably good if you use the stretched part as the first to wrap.
I would take exception to how the wires were soldered.
They should be on the same axis.
For thick multi-strand wire like that try this...
Strip the wires 5-10mm or so, and push the strands into each other lengthwise.
Make sure nothing sticks out, and then solder the connection.
Then finish off with tape, or heat-shrink (better).
Leo..
Indeed, its rarely used by qualified electricians (other than to colour-code wiring). Strictly for bodging stuff in a hurry, low voltage, or for labelling purposes. I would treat it a temporary solution (it leaves a horrible sticky residue). Its stretchiness is useful for conforming to odd shapes if you stretch it tight - you can achieve some level of weatherproofing as a result of this property. However it tends to pull back over time to relieve the stretch.
Insulation inside equipment often uses kapton film or tape which is stable over time, and tolerates heat very well. You can recognize kapton as its a dark orange colour and transparent. Alas its not stretchy and doesn't work well for bodging wire connections.
A great way to join wires is using heat-shrink tubing and hot-melt glue - the soldered joint is annointed in hot melt glue, heat shrink tubing placed over and heated - the tube shrinks, traps the glue, which melts and starts to extrude out of the ends. This can be pretty water-proof, yet retains some flexibility acting as strain-relief.
Tape glue tends to degrade with time, talking years. Heat shrink lasts much longer
Indeed, its rarely used by qualified electricians (other than to colour-code wiring). Strictly for bodging stuff in a hurry, low voltage, or for labelling purposes. I would treat it a temporary solution (it leaves a horrible sticky residue). Its stretchiness is useful for conforming to odd shapes if you stretch it tight - you can achieve some level of weatherproofing as a result of this property. However it tends to pull back over time to relieve the stretch.
Today this is probably true. However when I was in college working part time for a master electrician crimps and electrical tape were the norm. Horrible sticky residue + having to cut the wire at the crimp when changing anything was not optimum.
Insulation inside equipment often uses kapton film or tape which is stable over time, and tolerates heat very well. You can recognize kapton as its a dark orange colour and transparent. Alas its not stretchy and doesn't work well for bodging wire connections.
Kapton's greatest characteristic is that is does not cold flow (like teflon). I've only seen it used in military applications on certain cables. Here is has some drawbacks as well as it cannot be extruded so it must be wrapped around the wire(s).
A great way to join wires is using heat-shrink tubing and hot-melt glue - the soldered joint is annointed in hot melt glue, heat shrink tubing placed over and heated - the tube shrinks, traps the glue, which melts and starts to extrude out of the ends. This can be pretty water-proof, yet retains some flexibility acting as strain-relief.
Again this is true but it is not allowed, or more specifically "heat-shrink tubing isn't specifically designed or approved for this use, per NEC 110.3(B)". So it isn't acceptable in a mains junction box.
In the UK you need to use terminals to join wires, twisting wires together is not gonna do
In the USA the most common connections for mains wire to wire connections are "wire nuts"
Telecommunications services use heatshrink which is lined with hot melt glue, not generally for single wires, but for whole cable joins, but it would be available in all sizes.
Heating both shrinks the tube and melts the glue, creating the necessary waterproof seal of the join.
I've purchased some heatshrink lined with hot melt from Digikey, its not uncommon.
However recently I had tried shooting hotmelt into the heatshrink when it was already on the wire. It worked much better than I would have expected. In this case the heatshrink was used on a thermocouple end so squirting it in the end was easy and I was able to force it to the other end of the HS piece.
However it is limited in max temperature.
You can also try squirting silicone glue in the tube prior to shrinking.
This makes a very good moisture resistant connection.
I agree but it seems no matter how I do it .... it gets messy
Horribly
You need to be careful which silicone formulation though - some are acid curing and should never be used for electronics as the acid dissolves the wiring over time. Acid curing silicone smells strongly of vinegar when curing as the acid generated is acetic acid.