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- Thread starter 333rocky333
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As I said, it will remain an 'electrically sound connection' so long as the two nuts remain 'locked together (through the washer-lug-washer innards of the 'sandwich'), but will cease to be a 'sound electrical connection' if the nuts 'come loose'. However, as I also said, if one of the nuts were also tight up against something, the risk of that 'coming loose' would be reduced. I can understand them not wanting a nut tightened against that slightly concave edge of the resin, but that could be addressed with a sufficiently fancy (maybe 'box') washer.
Same answer as above. Obviously not mechanically sound in terms of mechanical attachment of the gland to the enclosure but, electrically speaking, the same as above - i.e. electrically sound so long as the two nuts remain 'locked together (this time through the banjo innards of the 'sandwich'), but will cease to be a 'sound electrical connection' if the nuts 'come loose'. Again, if the inner nut were tightened up to the uinside of the enclosure, then the risk of that 'coming loose' would probably be reduced.
A tapped hole in what?
Kind Regards, John
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I was taught the same by Donny Cables.
So if I understand correctly, in your opinion this is a good design?
with the first nut tightened for mechanical stability then the second nut for electrical.
In the side of the gland, there used to be either a flat or a lump with flat top drilled and tapped and usually supplied a 2 or 0BA slotted roundhead screw. The position crudely shown in red above.
This is a completely unrelated product but it gives an idea
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Pretty 'good
It would certainly be my opinion that it would be less likely (than your previous drawing) to suffer from a subsequent deterioration of the required electrical continuity between banjo and gland (due to 'coming loose').Not really for that reason, as you have stated it. Rather, with the first night tightened against something rigid so that tightening of the second nut against it (with intervening banjo) would produce a more 'reliable' (likely to last) adequate electrical connection between banjo and gland body.
Ah, right. I've seen such things on products such as you illustrate but never, that I can recall, on an SWA gland.
To keep all this discussion in perspective, we might perhaps consider the fact that I would imagine that the iffiest part of the 'earth path' is nothing to do with anything we've been discussing but, rather, the connection between the cable's armour and the gland.
Kind Regards, John
socket version of the PL259
OK so my reading of this is you are generally happy with '2 nuts' approach and from previous posts a hesitancy with the single nut version, in other words you prefer the older system of installing the gland.Pretty 'good
Not really for that reason, as you have stated it. Rather, with the first night tightened against something rigid so that tightening of the second nut against it (with intervening banjo) would produce a more 'reliable' (likely to last) adequate electrical connection between banjo and gland body.
Ah, right. I've seen such things on products such as you illustrate but never, that I can recall, on an SWA gland.
To keep all this discussion in perspective, we might perhaps consider the fact that I would imagine that the iffiest part of the 'earth path' is nothing to do with anything we've been discussing but, rather, the connection between the cable's armour and the gland.
Kind Regards, John
The 'earth point' was there way, way back, starting with the cast iron pots then on to the earlier brass versions. The it seemed to make sense to do away with the 'external earth point' and move it inside the enclosure with a banjo, early versions of which were bent and never intended to be bolted to the enclosure.
I don't believe I'm aware of anyone else having concerns about the integrety of the SWA to gland connexion when correctly installed onto the cable. Perhaps we should do away with it, afterall there is no regulatory requirement for it.
Yes it's a plug to socket [PL259 to SO239] lightening arrester. For information the format is originated as a screened 4mm banana plug/socket.
As I've said, the '2 nuts' approach is what I've always used with plastic boxes, primarily because I'm more confident of the 'longevity of tightness' when the banjo is between two metal nuts that have been 'tightened together' than when there is just a single nut with plastic as one of the materials that has been 'tightened onto' by a single nut.
As for metal boxes, I have never used a banjo, because I don't see the need. In fact, given that you have agreed that the material (brass or steel) is not an issue, I'm a little surprised that you see a need, either ...
... with a metal box, with or without a banjo the earth path is essentially the same (other than for the material). In both cases, the gland is clamped to 'a piece of metal' (by a locknut) and the CPC lug is bolted (with a nut and bolt) to another place on that 'piece of metal' - that 'piece of metal' forming part of the earth path. The only difference is that in one case the 'piece of metal' is a brass banjo and in the other case it is part of the steel box. So, if you don't think the material is, in itself, an issue, I don't really understand why you think it is 'better' with a banjo.
To take an extreme case, what if it were a brass box? Would you still feel it 'best' to bolt a brass banjo onto that brass box (ussing the gland's locknut and a nut/bolt) - and, if so, what would you believe it was achieving? If you wouldn't, then it would seem that, despite what you've said, your concern about a steel box without a banjo must relate to the (steel) material, mustn't it?
I have to say that, even now (with plastic enclosures), I quite often bend the banjo and do not bolt it to the (plastic) enclosure, particularly if it is to be installed outdoors, since there seems no point (and downsides, if outdoors) in drilling an unnecessary hole in the enclosure for that purpose.
I don't have any particular concerns about it. My point was that if one wants to do 'barrel scraping' as regards potential theoretical/hypothetical issues concerning the 'earth path', then I would have thought that the armour/gland interface would be at least as great a cause for theoretical/hypothetical concerns as the issues we've been discussing.
There are, indeed, other ways in which it could be done, but I suspect that any alternative method of connecting to the armour would be at least as iffy as (probably more iffy than) an 'SWA gland'.
Kind Regards, John
Yep, I knew a banana would fit.
The only alternate method I have ever seen, was to remove a narrow strip of the outer PVC, then use an earth clamp. I'm not sure I was impressed with that, or not. I can't remember what they used for glands, pre-PVC armoured cables - other than the lead type armoured cables.
Have you never seen the armour pulled away from the cable, twisted, stuffed into a bit of G/Y sleeving and then connected to some sort of terminal?
Kind Regards, John
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