Adam has given the correct answer here. I've been doing this for years and never had an issue.
is it me
- Thread starter russellsmiler
- Start date
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A screw is simply a long mechanical wedge, what keeps it in place is friction; if it is subjected to a temperature cycle with varying current loads, there will be a continual relaxation of this friction. This is the reason why screws on electrical equipment, can always be retightened to an extent.
Push in connectors of the maintenance free variety (MF), won't suffer from this effect, since the spring connection expands and contracts with cycles of heating and cooling.
Regards
Push in connectors of the maintenance free variety (MF), won't suffer from this effect, since the spring connection expands and contracts with cycles of heating and cooling.
Regards
Will we see push-in terminals on MCBs, incomers etc?
I really do hope not.
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I may be wrong, but I suspect that most of us probably seriously doubt that we will see such things any time soon (if ever) - which does make one wonder about the faith that some seem to have in spring connections!
Kind Regards, John
They have their place, reliant on physical limitations, hence the classification of MF. Larger current ratings are entirely feasible, but the size of components would not be acceptable. Current ratings for screw terminals on MCB's etc., are adequately dimensioned to give an adequate lifetime .... provided that they are efficiently torqued up at the installation point.
Very large current ratings of course rely on bolting and Spring/Belville washers etc., to maintain the pressure of the contact faces, during expansion and contraction.
Regards
We should go back to two screw connections like on old wylex fuse boxes. Virtually unheard of for those connections to fail.
Very much so. I've kept a few of them in a dusty corner of my cellar, since they are one of the best-engineered bits of domestic electrical kit I've ever come across. I might 'frame' one of them one day! Why the idea of two screws didn't spread, and perpetuate, I'll never know,
Kind Regards, John
Cost ?
Sad though it is, you could well be right.
The most daft argument against double screws that I've ever heard is that one of them can seriously loosen 'without any problem becoming apparent'!
Kind Regards, John
S
SaladFingers
I recently had to replace a busbar and breaker as the scew terminal securing the connection to the busbar were lose and had burnt both the bar and the breaker. Something like that though, was more likely whoever installed the breaker in the first place.
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