I was not considering mechanical protection as that is not a requirement for earthed metallic coverings.
That was my point - that earthed steel capping offers the same protective functionality as the 'earthed metallic coverings' of pyro or ali-tube, but with the additional benefit of a (limited) degree of mechanical protection - hence 'at least as good as' (probably 'a little better than') than those two types of cable with earthed metallic coverings.I was not considering mechanical protection as that is not a requirement for earthed metallic coverings.
I did, and will correct it. Thanks for noticing!I guess you meant >50mm
That's all well and good if you know what that's bounce means! Otherwise people just give it another whackThe good thing about metal capping, is the telltale 'bounce' you get when knocking a nail in, or drilling
Or the connection can be MF. How about crimping a ring terminal onto the cable and a pop-rivet to attach it to the capping ?it cannot be completely buried as the earthing connection must be inspectable
That's true. Or pop-rivet the pieces together with an overlap joint ?it would be difficult to earth several pieces together for the typical cable runs.
Well, I suppose one could argue that a pop-riviter was an "appropriate compression tool". Failing that, one could perhaps use a 'rolled/folded joint', created with an "appropriate compression tool" (essentially the same concept as crimping) or could weld, solder or braze (not so sure about brazing steel!) bits of capping together (and use any of those techniques, including crimping, for attaching cables to the capping).Is a pop-rivet one of the suitable methods for inaccessible joints? I don't know.
Indeed. If a crimp connection is accepted for solid cores ( I was taught otherwise as an apprentice ) then I fail to see why a pop-rivet shouldn't be permitted. I'd use a steel (or stainless steel) rivet to avoid any electrolytic corrosion issues.Well, I suppose one could argue that a pop-riviter was an "appropriate compression tool".
That assumes that the cable under the capping is "most" of the run. What about where it's just part of the run - do you use large amounts of (say) SWA just because a couple of yards needs it, while the other 10, 20, whatever yards could be just T&E ?However, as you say, it would be simpler to just use an appropriate cable - which, for most of us, would probably mean SWA (pyro needing skills and equipment, and ali-tube being expensive and difficult to find).
Glad you agree. I, too, was 'taught' that - albeit 'informally'.Indeed. If a crimp connection is accepted for solid cores ( I was taught otherwise as an apprentice ) then I fail to see why a pop-rivet shouldn't be permitted. I'd use a steel (or stainless steel) rivet to avoid any electrolytic corrosion issues.
That's a reasonable point. I suppose that if one used acceptable jointing methods (for inaccessible joints) (albeit the armour would be 'interesting'), one could just use SWA where needed, with T+E for the rest - but that sounds just slightly 'orrible!That assumes that the cable under the capping is "most" of the run. What about where it's just part of the run - do you use large amounts of (say) SWA just because a couple of yards needs it, while the other 10, 20, whatever yards could be just T&E ?
It's not. That others do it because others do it does not alter the fact.If a crimp connection is accepted for solid cores ( I was taught otherwise as an apprentice )
FWIW, I was also 'taught' that, even with stranded conductors, it was not really very satisfactory to use tools that just did "one-plane squashing" (such as the tools advocated here, and almost universally used by electricians).It's not. That others do it because others do it does not alter the fact.
I'm an old fart, but not that old!!
I'll try and find out.
That's all true, but passive constraint in the second axis is not the same (or anything like as 'good') as active pressure being applied in two (or, more commonly, three) axes. I may be wrong, but I think you'll find that when, say, DNOs crimp massive cables, they wouldn't dream of using anything less than a 'hex' (i.e. 3-axis) (hydraulic) crimper.As to one plane squashing, I think it's not so much that, as whether there is constraint in the second axis. The cheap "pliers" only squash the terminal to an oval, and leave plenty of room for the strands to move sideways - so a joint with poor integrity (as I remember from the past when I had a few poor joint on a car I'd done a lot of wiring on ). The ratchet crimper I have, while only being a cheap set, constrains the terminal in that plane, so while the result is still an oval there is limiter scope for the strands to move.
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