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Torque settings

Jam
Hi all,


Obviously, where available we use manufacturer's torque settings for connections. But where do they get them from?


I ask this not least because it's not always easy to obtain, at least in a timely fashion, but also because I appear to have conflicting instructions on some OEM'd equipment (comparing the original manufacturer with the wrapped supplier) or notably different settings when using the same lug onto a very similar terminal bar from a different supplier. It would also be helpful to be able to sense-check the answers for misplaced decimal points.


Jam
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    Jam:

    Hi all,


    Obviously, where available we use manufacturer's torque settings for connections. But where do they get them from?


    I ask this not least because it's not always easy to obtain, at least in a timely fashion, but also because I appear to have conflicting instructions on some OEM'd equipment (comparing the original manufacturer with the wrapped supplier) or notably different settings when using the same lug onto a very similar terminal bar from a different supplier. It would also be helpful to be able to sense-check the answers for misplaced decimal points.


    Jam




    I never use a torque screwdriver when tightening electrical terminal screws or torque wrench bus-bar bolts and have never had any trouble. It is all down to experience. Some may say that I am wrong. Experience teaches that if you tighten up a screw too much it may strip the thread or break the part involved. So if you do that once you don't do it again. I have a torque wrench for my car repair work as that is very important. I don't want to break a stud or camshaft bolt and have difficulty in removing it afterwards, or strip a thread.  That would be a very expensive mistake.


    If electrical terminal screws are too loose then the conductor may run hot under load. I tighten and then do the wiggle test to see if the conductor is well secured in the terminal, then I re-tighten a little bit more, just a bit. M.C.B. clamp terminals are never to be over tightened as they can distort. I double over single solid conductor ends, but leave stranded conductors untwisted and then  let the clamp terminal grip the strands evenly.


    With new consumer  units I tighten all screws well. Sometimes I wire up R.C.B.O.s before positioning them in their final locations. When I have installed all M.C.B.s and R.C.B.O.s I then finally check EVERY terminal screw for tightness, as I may have disturbed a cable termination whist working. I check ALL screws before replacing the consumer unit cover.


    Z.

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  • 0

    Jam:

    Hi all,


    Obviously, where available we use manufacturer's torque settings for connections. But where do they get them from?


    I ask this not least because it's not always easy to obtain, at least in a timely fashion, but also because I appear to have conflicting instructions on some OEM'd equipment (comparing the original manufacturer with the wrapped supplier) or notably different settings when using the same lug onto a very similar terminal bar from a different supplier. It would also be helpful to be able to sense-check the answers for misplaced decimal points.


    Jam




    I never use a torque screwdriver when tightening electrical terminal screws or torque wrench bus-bar bolts and have never had any trouble. It is all down to experience. Some may say that I am wrong. Experience teaches that if you tighten up a screw too much it may strip the thread or break the part involved. So if you do that once you don't do it again. I have a torque wrench for my car repair work as that is very important. I don't want to break a stud or camshaft bolt and have difficulty in removing it afterwards, or strip a thread.  That would be a very expensive mistake.


    If electrical terminal screws are too loose then the conductor may run hot under load. I tighten and then do the wiggle test to see if the conductor is well secured in the terminal, then I re-tighten a little bit more, just a bit. M.C.B. clamp terminals are never to be over tightened as they can distort. I double over single solid conductor ends, but leave stranded conductors untwisted and then  let the clamp terminal grip the strands evenly.


    With new consumer  units I tighten all screws well. Sometimes I wire up R.C.B.O.s before positioning them in their final locations. When I have installed all M.C.B.s and R.C.B.O.s I then finally check EVERY terminal screw for tightness, as I may have disturbed a cable termination whist working. I check ALL screws before replacing the consumer unit cover.


    Z.

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