Inside Radius

[STI]

Sorry for probably a very basic question but i have read that when you are bending a cable care needs to be taken to ensure that the inside radius is ok.

Can someone please explain where the inside radius is measured from. Ive looked on various sites and searched this one but it seems to be as easy to find as a certain G spot.

Thanks

 

[LoveRocket]

Do you mean "minimum bend radius"?

Is so, if you were to bend a wire in to a circle of the specified radius, this is a tight as you can safely bend the wire.

 

[STI]

I do and thanks. Now to find a compass

 

[holmslaw]

..

 

[STI]

Holmslaw thanks. By ripple does this also mean if the grey sheath starts to go lighter its also too tight.

I ask the original question because of the lighting wiring problem i had in an earlier post. The 1.5mm cable has been clipped to a joist up the side across the top back down the other side so two bends are close to being a right angle. Which i thought may contravene the minimum bend radius and help explain why the conductors are so brittle. It certainly explained why i couldnt get any excess wire to rewire the bl**dy things. That said i couldnt see any signs of damage to the cable externaly except a slight lightening of the cable at the bend.

 

[ban-all-sheds]

http://www.tlc-direct.co.uk/Book/4.4.2.htm

 

[holmslaw]

..

 

[STI]

Whats the context for mentioning brittle cables

I was having problems with a light fitting, in short it had become disconnected and when i tried to bring some cable down to reconnect it, i couldnt. Then when i tried to reattach it to the terminal the conductor kept just snapping. ( not overtightening it literally snapped just by moving it slightly)I found out that there had been a water leak onto the ceiling area this cable came through thought this may have caused it, then read about the minimum radius and thought perhaps that had done it. I just had never come across such brittle cable before where ther was no obvious sign of damage or overheating etc.

 

[STI]

http://www.tlc-direct.co.uk/Book/4.4.2.htm

Thanks BAS this is a place i did look after doing the search but although it describes what it is, it doesnt realy describe what it is you are looking at/measuring to make sure it meets the minimum. Unfortunately before i read the item you point at i found some metal work site that described the measurement point as the line between the point where the curve starts and ends but the diagram that came with it showed this as a straight line, the diameter if you will of the circle. A bit confusing So i thought i would come to the experts to get a clear answer.