What is this - an external isolator?

[JohnW2]

That's an easy one to answer, just go back 4 posts to #68

Hmmm. I think you're probably getting close to losing me and/or my patience

I can but presume that you are referring to your approach (which you regard as 'Best Practice), which appears to not be what the manufacturers of gland kits now intend, of using two or three nuts, and that you feel that it is somehow 'bad practice' for the 'nut-tightened electrical joint' to also ('happen to') hold the gland body to the box?

If you did what the manufacturers now presumably intend (since they now supply only one nut), it would presumably be pointless to use a brass banjo (in contact with the box) with a brass box, wouldn't it?

Kind Regards, John

 

[JohnW2]

It means they have established that parts of their packs are being thrown away [second nut] by people not understanding or refusing to follow MIs and accordingly reduced the quantity of nuts supplied as a means of increasing their profit.

Are you saying that they have MIs which specify that one should use two nuts per gland but supply only one nut per gland?

[ None of the kit packs I have contain any "MIs", so I'm going to have to hunt online to see what I can find ]

Kind Regards, John

 

[SUNRAY]

Perhaps, but since I doubted that you actually do use brass boxes, I wasn't sure whether or not "I do still use a banjo" was an answer to my question.[it would hjave been 'easier' (at least, clear) had you written something like "I would still use a banjo"].

I fail to see the confusion;
Q, would you still feel the need for a banjo?
A, I do still use a banjo. [Note 'do' and not 'would']

Anyway, now that is cleared up, can you help me understand why you would use a brass banjo when attaching a brass gland to a brass box?

Kind Regards, John

That's easy

just go back 4 6 posts to #68

 

[JohnW2]

I fail to see the confusion; Q, would you still feel the need for a banjo? A, I do still use a banjo. [Note 'do' and not 'would']

This is getting rather silly.

There would be no confusion if you do actually use brass enclosures, but I had assumed (perhaps wrongly) that you don't.

If you do not use brass enclosures, then I really don't know what (of relevance) "I do still use a banjo" would mean.

 

[SUNRAY]

Are you saying that they have MIs which specify that one should use two nuts per gland but supply only one nut per gland?

[ None of the kit packs I have contain any "MIs", so I'm going to have to hunt online to see what I can find ]

Kind Regards, John

No not any more because they found they were being ignored and not only that, some now supply steel nuts, I dare say down to cost and it's only a matter of time before the last of those change to steel too.

 

[SUNRAY]

This is getting rather silly.

There would be no confusion if you do actually use brass enclosures, but I had assumed (perhaps wrongly) that you don't.

If you do not use brass enclosures, then I really don't know what (of relevance) "I do still use a banjo" would mean.

I have used all sorts of enclosures over the years; PVC, ABS, nylon, polyethylene, mild steel, galve, pasivated, aluminium, alunimium alloy, anodised, brass, copper, A2, A4, 316 stainless steel, zinc, cast iron, lead, silver, gold and I dare say some that haven't sprung to mind. Various locations have different requirements such as bakeries; stainless steel or stabilised nylon, intrinsically safe; cast iron and copper, Open cell battery rooms; ABS [limited colours], polyethylene [limited colours] or lead, Marine uses a lot of cast or plate brass, etc.

 

[JohnW2]

No not any more because they found they were being ignored ...

If you're saying that the MIs now say that one should use just one nut, is it not necessary to consider what assertions can reasonably be made about what is 'acceptable' (or 'good', or even 'best') practice? You were previously talking about 'ignoring MIs', but it seems that such is not necessarily what people (who don't do as you like) are doing

.... and not only that, some now supply steel nuts, I dare say down to cost and it's only a matter of time before the last of those change to steel too.

I suppose that, if they are 'instructing' the use of a single nut, and if they assume that the most common metal boxes/enclosures are steel, then the material of the nut probably doesn't matter all that much - a brass nut (or, if used, a brass banjo) would be in contact with the steel box, whereas a steel nut would be in contact with the brass gland body (and brass banjo, if used).

 

[Harry Bloomfield]

Surely it would make more sense to not introduce ferrous metals into the equasion, would it not?

Ever wondered why mineral insulated cable is made of... oo let me see...

Copper, obviously, but I half remember an alloy version briefly, maybe?

 

[SUNRAY]

Copper, obviously, but I half remember an alloy version briefly, maybe?

Yes that's the whole point Harry, it's made of non ferrous copper.

I'd forgotten about the Ali version, I'm not sure but I think it originated in USA. Luckily the silly fad lasted about 3 weeks, or so it seemed.

 

[SUNRAY]

All of a sudden I've found the link to this sensible alternative to the brass gland, these are zinc passivated brass fittings and can form the MET in an enclosure depending on the quantity of earth wires required.

I'm not trying to say these are suitable for pics in OP, in fact just the opposite.

 

[JohnW2]

All of a sudden I've found the link to this sensible alternative to the brass gland, these are zinc passivated brass fittings and can form the MET in an enclosure depending on the quantity of earth wires required. ....

Interesting. I've certainly never seen anything like that, although I have seen some (I imagined you would call 'botched') jobs that have done ad-hoc things (with earth clamps, jubilee clips etc.) that attempt a similar concept.

However, other than for the three termination points, what advantages do you see this offering over a 'proper gland'? On the downside, it seems that they will take up a fair bit of space within an enclosure, probably usually/often requiring a much larger enclosure than would be needed with regular glands (e.g. in the example that Rocky posted in the other thread)?

Kind Regards, John

 

[SUNRAY]

Interesting. I've certainly never seen anything like that, although I have seen some (I imagined you would call 'botched') jobs that have done ad-hoc things (with earth clamps, jubilee clips etc.) that attempt a similar concept.

However, other than for the three termination points, what advantages do you see this offering over a 'proper gland'? On the downside, it seems that they will take up a fair bit of space within an enclosure, probably usually/often requiring a much larger enclosure than would be needed with regular glands (e.g. in the example that Rocky posted in the other thread)?

Kind Regards, John

My apologies, I forgot this is not Rockys thread, It's those boxes I meant to say they would not be suitable for. However in the case of the SWAs where the armour has been terminated in the trunking these would be far more suitable and a fraction of the cost.

Interestingly you mention enclosure size, this arrangement is very commonly used in street furniture where space, or more correctly access, may be limited.

 

[JohnW2]

My apologies, I forgot this is not Rockys thread, It's those boxes I meant to say they would not be suitable for.

Fair enough.

Interestingly you mention enclosure size, this arrangement is very commonly used in street furniture where space, or more correctly access, may be limited.

Unless I'm misunderstanding, the whole of one of those things has to be accommodated within the enclosure, whereas with a standard SWA gland, only a tiny bit of it is within the enclosure - which surely means that the SWA glands are more suitable if space within the enclosure is limited?

Kind Regards, John

 

[SUNRAY]

Unless I'm misunderstanding, the whole of one of those things has to be accommodated within the enclosure, whereas with a standard SWA gland, only a tiny bit of it is within the enclosure - which surely means that the SWA glands are more suitable if space within the enclosure is limited?

Kind Regards, John

think about this one of Rocky's:

And that big ol' lump of brass glands/banjos filling up the trunking.

The CET devices are not designed to be correct for every job, just as brass SWA glands are not.

 

[JohnW2]

think about this one of Rocky's: .... And that big ol' lump of brass glands/banjos filling up the trunking.

Sure - in that situation (with the entirety of the glands within the enclosure' {trunking}), the alternative approach might well take up a bit less space.

However, I was obviously talking about the 'normal' situation in which ~95% of the gland is outside of the enclosure, in which case it's fairly obvious which requires the least space within the enclosure.

Kind Regards, John