Torque screwdriver settings

[The Ghost]

I find that when you tighten on stranded 16mm² and go back after five minutes the copper has "relaxed" and you can tighten slightly more. If you solely rely on a torque screwdriver you might be falsely believing that all is good. As you may be thinking "it clicked" job done and give it no more thought.

 

[Pete999]

I find that when you tighten on stranded 16mm² and go back after five minutes the copper has "relaxed" and you can tighten slightly more. If you solely rely on a torque screwdriver you might be falsely believing that all is good. As you may be thinking "it clicked" job done and give it no more thought.

Think you could apply that theory to most stranded conductors Vortigern, I always used to go back and tweak terminals before the onset of torque screwdrivers.

 

[Midwest]

Think you could apply that theory to most stranded conductors Vortigern, I always used to go back and tweak terminals before the onset of torque screwdrivers.

And any method of tightening.

 

[davesparks]

I find that when you tighten on stranded 16mm² and go back after five minutes the copper has "relaxed" and you can tighten slightly more. If you solely rely on a torque screwdriver you might be falsely believing that all is good. As you may be thinking "it clicked" job done and give it no more thought.

Correctly torqueing a fastener involves allowing a period of time for the fastener to relax and then re-torqueing it, also for larger values of torque it should be applied in stages.

 

[Midwest]

Correctly torqueing a fastener involves allowing a period of time for the fastener to relax and then re-torqueing it, also for larger values of torque it should be applied in stages.

Said the Actress to the Bishop.

 

[1Justin]

I use one, more as a box-ticking exercise I have to say. I've been meaning to put it in the vice with kitchen weights and check the calibration since the "click" doesn't always feel appropriate, give or take, depending on the make-up of the conductor in the clamp.
Some MCB's will damage fine conductors at recommended torque, and that stacks up. The pressure on (for example) a doubled over T&E strand may be approximately half that of a single strand, and arguably at the same torque, a single strand of 1mm T&E might be subject to perhaps three times the pressure of the multiple strands of a 6mm T&E.
Torque settings, given the number of uncontrolled variables in what's being clamped at the top of an MCB are IMO really a method that NICEIC etc can be shown to be "doing their bit". For those at least, the calibrated elbow can be a better judge and can cater for the other variables in a more nuanced way, but we are not encouraged to say that.