Dodgy trade pictures for your amusement! - 1 Million Views!

[Darkwood]

Right ... Just been nudged to set this up by Paul.M and sounds a good idea following recent threads I've done in the Arms..

Rules....No Offensive material... edit if required before posting as this is the public arena.
Anything to do with the trade or in and around it ...H&S pic's welcome.



I've posted this a few times and this is at a mates house following a kitchen refirb several yrs ago. mg_smile:

 

[Raptor0014]

The angle of a bend is less important than the radius of that bend. The cables we bend are manufactured to a standard and there are minimum bend radii for cables manufactured to those standards.

As per previous post, bending the end of a solid conductor is simply to increase surface area within a terminal signifcantly larger than the conductor - it's basically a means of avoiding the a situation where conductors aren't properly terminated.

The other issue of solid links within a CU is entirely separate as we don't know what standards those links are manufactured to and can safely assume that all factory fitted components have been type tested.

I’m aware of the reason for the bending of conductor termination and radii of cable bends.

I just don’t understand the aversion of some to bending of cables as long as they aren’t going over the bend radius tolerances.

If they were bent like the termination bends I’d understand.

 

[nicebutdim]

I don't think anyone has objected to the bending of conductors within specified radii.

 

[Dustydazzler]

You have to be pretty ham fisted to bend a cable to the point of snapping it clean in two

 

[brianmoooore]

Copper is a strange material. In its annealed form (heated to a dull red and cooled slowly) it is extremely ductile, and can be bent pretty much how you like, but just the once. After that, it 'work hardens' with each successive bend making it harder and less ductile, until it becomes almost brittle, and breaks easily if bent. The only way to make it ductile again is to heat it to dull red and slowly cool, which can be somewhat difficult if it is covered in PVC insulation.
I play around with copper pipes as well as wires, and have made thousands of bends in 15mm and 22mm tube. The correct wat to do this is to start with Table X copper tube, which is annealed to the correct degree, then to bend it slightly more than you require, before straightening it back to the angle you wanted. This is to leave the tube in a less stressed state than it would be after the initial bend.

 

[Simon47]

Bending a multi-core cable is totally different to bending a single-core conductor. In a multi-core cable the outer conductors are stretched but the inner conductors are compressed.

OK, I'm starting with a significant "IF" here ...
If the cable is at least half decently made, then what should happen is the individual components will slide about within the cable. A core that is on the inside of the bend at one point, will be on the outside a short distance along it - hence by sliding along relative to the other components there should be minimal stress. Within the core, the same thing should happen with the individual strands.
You can see this in action quite well with coarsely stranded cables. Who hasn't nicely prepared an SWA cable, only to find the strands of the armour are all different lengths when you move it into position - and then you curse yourself for not keeping the right bends in place while you were cutting back the armour Similarly with the main tails when the nice neat ends are no longer nice and neat once you get that last bend into it.

The min bend radius will depend on several factors - including how well the components can slide about within the cable. In part, there will be a factor of ensuring that any bend will encompass the twist lengths - a tight bend radius with a long twist length won't guarantee that a component that's in compression inside the bend will also be in tension on the outside a little further round.

 

[Mike Johnson]

That is assuming that the molecular structure of copper is not linear, it seems that it is hence its good conductivity, therefore, the compression or tension will be constant along its length of the bend.

 

[telectrix]

just like any other material, copper can suffer from fatigue if bent too much, too often. just look at these girls' waists/hips:

 

[pc1966]

just like any other material, copper can suffer from fatigue if bent too much, too often. just look at these girls' waists/hips:

What great 60s outfits!

Groovy man!

 

[pirate]

Does the science about bending copper wire discussed above apply to the "uni-directional" speaker cables beloved by some hi-fi enthusiasts?

 

[DPG]

Does the science about bending copper wire discussed above apply to the "uni-directional" speaker cables beloved by some hi-fi enthusiasts?

Uni directional cables definitely sound better when the strands are twisted clockwise.

 

[Raptor0014]

Uni directional cables definitely sound better when the strands are twisted clockwise.

But if you put the speakers at the other end, then stand at the opposite side of the room to the speaker. Anti-clockwise twists and 67deg curve are best.

 

[pirate]

Thanks for that useful advice! I didn't want to buy that expensive speaker cable then mess it up on the installation. I usually twist the cable anti-clockwise, so the bludi sound would have been going the wrong way!

 

[DPG]

Thanks for that useful advice! I didn't want to buy that expensive speaker cable then mess it up on the installation. I usually twist the cable anti-clockwise, so the bludi sound would have been going the wrong way!

Yes, you don't want the sound going back into your amplifier. Schoolboy error.

 

[pc1966]

Yes, you don't want the sound going back into your amplifier. Schoolboy error.

They don't like it up 'em, captain Mainwaring!

 

[Raptor0014]

“ but when the cover is closed then there’s no access….”

Great use of conduit and gland too.