New Consumer Unit

[ban-all-sheds]

Then I would say that you would need to add external restraints.

 

[JohnW2]

I don't know the answer to those any more than you do, but what I do know is that my ignorance and lack of understanding are not reasons to dismiss what the makers say is the way to install their products and assume that I must know better.

No, it's not. However, unless/until someone gets credible (and evidence-based) clarification/explanation from the manufacturers, my personal practice will be to continue to do what I've always done, and what I sincerely believe the great majority of electricians have always done (i.e. not leave terminals so loose that they "do not appear to be safe"). If you, or anyone one else, wants to do something different, that's clearly your/their prerogative.

Kind Regards, John

 

[Risteard]

one could 'waggle the conductor around' and easily get half a turn, or maybe a whole turn, more with a screwdriver without much effort?

Have you tried retorqueing the terminals after your wiggling operations?

 

[JohnW2]

one could 'waggle the conductor around' and easily get half a turn, or maybe a whole turn, more with a screwdriver without much effort?

Have you tried retorqueing the terminals after your wiggling operations?

I honestly can't remember (it was quite a long time ago), but I probably did. However, that's not really the point. I by no means always 'wiggled'. The worrying thing was that I could usually (easily, without much effort) get anything up to a whole turn more with a screwdriver immediately after it had been torqued. As I've said, I find it hard to believe that (m)any electricians would be happy to leave a terminal screw that loose (even if, per BAS's argument, they are all wrong).

Kind Regards, John

 

[Risteard]

one could 'waggle the conductor around' and easily get half a turn, or maybe a whole turn, more with a screwdriver without much effort?

Have you tried retorqueing the terminals after your wiggling operations?

I honestly can't remember (it was quite a long time ago), but I probably did. However, that's not really the point. I by no means always 'wiggled'. The worrying thing was that I could usually (easily, without much effort) get anything up to a whole turn more with a screwdriver immediately after it had been torqued. As I've said, I find it hard to believe that (m)any electricians would be happy to leave a terminal screw that loose (even if, per BAS's argument, they are all wrong).

Kind Regards, John

I think the advice is that you should wiggle the conductors around (which may cause displacement) and then retorque it. Then it should be tight.

 

[AndyPRK]

Maybe wiggle isn't the correct word.

Maybe gently pull.

 

[Risteard]

Maybe wiggle isn't the correct word.

Maybe gently pull.

Not to cause the strands to splay though - it is really a wiggle.

 

[JohnW2]

I think the advice is that you should wiggle the conductors around (which may cause displacement) and then retorque it. Then it should be tight.

Although 're-tightening after wiggling' (and after allowing some 'creep' of the copper conductor to occur) is wise after any initial tightening, regardless of the way it's being done ('manually' or with a torque screwdriver), I don't think it addresses the issue I'm talking about. Unless the tool is faulty, it will presumably tighten to the same torque the second time as well as the first - in which case, in terms of my experiences, it would again probably be easy to get a lot more tightening 'by hand', without much effort.

Kind Regards, John

 

[Risteard]

I think the advice is that you should wiggle the conductors around (which may cause displacement) and then retorque it. Then it should be tight.

Although 're-tightening after wiggling' (and after allowing some 'creep' of the copper conductor to occur) is wise after any initial tightening, regardless of the way it's being done ('manually' or with a torque screwdriver), I don't think it addresses the issue I'm talking about. Unless the tool is faulty, it will presumably tighten to the same torque the second time as well as the first - in which case, in terms of my experiences, it would again probably be easy to get a lot more tightening 'by hand', without much effort.

Kind Regards, John

Whilst it would be the same torque, the fact is that if the conductor has deformed slightly this will then cause the torque to be diminished. So whilst it may have been torqued to that setting, it isn't actually at that torque afterwards.

 

[ban-all-sheds]

However, unless/until someone gets credible (and evidence-based) clarification/explanation from the manufacturers, my personal practice will be to continue to do what I've always done, and what I sincerely believe the great majority of electricians have always done (i.e. not leave terminals so loose that they "do not appear to be safe").

Please don't take this as a personal attack on you - it applies to anyone who feels the same, but what that says is that you are going to continue to dismiss what the makers put in their installation instructions because you don't understand them, or why they are there.

 

[AndyPRK]

I can't see how the torque setting of a 1mm bit of wire can be the same as a tail ?

Using common sense you wouldn't want to break a 1mm piece of wire by over tightening, however the same torque when applied to a tail would leave it free to move. And you definitely don't want a loose tail.

 

[ban-all-sheds]

Is the recommended setting for a B6 the same as that for a 100A switch, 80A RCD etc?

I will ask you the question which nobody seems able to answer - why would a maker specify a torque setting which was inadequate? Consider the liabilities they would face if it could be shown that their inadequate spec was causing problems.

They must have done what they at least consider due diligence to arrive at figures, they must be sure that cables won't fall out or overheat. If people don't trust them to do that, I wonder what else they don't trust them to have got right.

 

[JohnW2]

Whilst it would be the same torque, the fact is that if the conductor has deformed slightly this will then cause the torque to be diminished. So whilst it may have been torqued to that setting, it isn't actually at that torque afterwards.

I don't think that explains my experiences. What I do remember is that, once I'd found what happened with a single 'torquing', I then often repeatedly 're-torqued' the screw before, again, finding that I could still easily get a lot more with a screwdriver.

Kind Regards, John

 

[JohnW2]

Please don't take this as a personal attack on you - it applies to anyone who feels the same, but what that says is that you are going to continue to dismiss what the makers put in their installation instructions because you don't understand them, or why they are there.

That's one way of wording it, and you are free to put it like that if you wish. I would prefer to say that unless/until I see some convincing evidence indicating that I should do otherwise, I am going to continue to do what, as I understand it, is what the great majority of electricians have regarded as the safe thing to do for decades.

Kind Regards, John

 

[JohnW2]

I can't see how the torque setting of a 1mm bit of wire can be the same as a tail ?

Quite so - but, to be fair, they do not specify the same torques for things likely to be accommodating 'tails' as for those likely to be accommodating 1mm² conductors. However, I've never seen them suggest more than one torque for a particular device - even though there will be appreciable variation in what conductors might be in its terminal.

Kind Regards, John