Thin singles for steel conduit

[JohnW2]

Oh yes but in all honesty being thicker wouldn't have helped.

Quite. If a T+E cable (of any size) 'breaks', it surely must have been 'abused' in a fairly major way?

 

[phatboy]

I think I could build a swing out of 1mm T+E, and it would last well!

 

[JohnW2]

I think I could build a swing out of 1mm T+E, and it would last well!

So do I.

 

[SUNRAY]

Quite. If a T+E cable (of any size) 'breaks', it surely must have been 'abused' in a fairly major way?

On a fairly long catenery probably 30m within a row of lamp standards, it failed at one end. This was a temporary repair along a river side, I'll guess it lasted over 20 years before sufficient table ties failed allowing big loops to form and presumably pull the cable tight. I assume the biggest factor was the wind. Currently ducts being laid to pull new cable in.

 

[Risteard]

The one thing I do find interesting is that all European countries I‘m aware of have a minimum requirement of 1.5 mm2 for
mechanical strength in fixed installations (except control circuits). The UK and Ireland are the only exceptions as far as I know.

The south of Ireland does not permit 1mm^2 conductors in fixed wiring.

 

[SUNRAY]

The south of Ireland does not permit 1mm^2 conductors in fixed wiring.

How silly

 

[SUNRAY]

Quite. If a T+E cable (of any size) 'breaks', it surely must have been 'abused' in a fairly major way?

I know 2.5mm² T£E didn't work very well as a tow rope

 

[Harry Bloomfield]

The one thing I do find interesting is that all European countries I‘m aware of have a minimum requirement of 1.5 mm2 for
mechanical strength in fixed installations (except control circuits). The UK and Ireland are the only exceptions as far as I know.

1/044 was allowed back in the day, for lighting circuits - The equivalent of 1mm.

 

[plugwash]

I'm seeing varying figures for the tensile strength of copper, preusmablly depending on how exactly it's prepared, but they generally fall into the range of 200-400 megapascals. So a 1mm² conductor would have a stregnth of 200-400 newtons. and the cable as a whole a stregth of 0.6-1.2 kilonewtons. So one fat guy could almost certainly break it under body weight. Under a dynamic load even a thin person is likely to be able to break it.

In reality though, I suspect in most cases, you will rip a cable out of it's terminations, before you outright break it.

 

[JohnW2]

I'm seeing varying figures for the tensile strength of copper, preusmablly depending on how exactly it's prepared, but they generally fall into the range of 200-400 megapascals. So a 1mm² conductor would have a stregnth of 200-400 newtons. and the cable as a whole a stregth of 0.6-1.2 kilonewtons. So one fat guy could almost certainly break it under body weight. Under a dynamic load even a thin person is likely to be able to break it.

I can think of few, if any, sensible/credible real-world situations in which an in-situ fixed-wiring cable would be subjected to the sort of 'stretching forces you are talking about. If anything 'broke' the conductors, I would expect it to be repeated flexing, leading to a fracture, but that's not going to happen with 'fixed wiring'.

In reality though, I suspect in most cases, you will rip a cable out of it's terminations, before you outright break it.

Quite so.

 

[SUNRAY]

I'm seeing varying figures for the tensile strength of copper, preusmablly depending on how exactly it's prepared, but they generally fall into the range of 200-400 megapascals. So a 1mm² conductor would have a stregnth of 200-400 newtons. and the cable as a whole a stregth of 0.6-1.2 kilonewtons. So one fat guy could almost certainly break it under body weight. Under a dynamic load even a thin person is likely to be able to break it.

In reality though, I suspect in most cases, you will rip a cable out of it's terminations, before you outright break it.

I haven't looked anything up but historically I've used a lot of 1 & 1.5mm² solid as metal ties and temporary holdy uppy type things, I've certainly had a few snap, especially when working with big SWAs, I think 400 Newtons is not unrealistic, I don't think it would be capable of supporting a 50Kg bag of cement.

 

[SUNRAY]

I can think of few, if any, sensible/credible real-world situations in which an in-situ fixed-wiring cable would be subjected to the sort of 'stretching forces you are talking about.

Well something would be very wrong with the design if any fixed electrical cable were so subjected.

If anything 'broke' the conductors, I would expect it to be repeated flexing, leading to a fracture, but that's not going to happen with 'fixed wiring'.

Indeed and when used as an electrical cable I've only known those flexing or otherwise damaged to fail that way.