Other peoples work

[JohnW2]

I am certainly not a housebasher, but i use banjos on steel boxes too, I always assumed it increased the brass to steel contact as opposed to not using one...

I'm not sure that I really understand the point/need for that. The electrical continuity between the lugs on the CPCs and the box will be so good that I wouldn't have thought that the banjo would make any significant difference. In fact, I would have suspected that having a mixture of materials being bolted together might slightly increase the risk of the connection 'coming loose'.

Kind Regards, John

 

[JohnW2]

I must be missing something, I see it as a reduction of joints

As done, each of the CPCs is bolted directly to the box. The only alternatives I can think of would be to connect the CPCs to 'something else' which, in turn, was somehow connected to the box. As I see it, that would be at least two 'connections' (between each CPC and the box), rather than just the one.

Kind Regards, John

 

[SUNRAY]

I am certainly not a housebasher, but i use banjos on steel boxes too, I always assumed it increased the brass to steel contact as opposed to not using one, nowadays i use earthing nuts which themselves have a greater brass surface area

I'm not sure that I really understand the point/need for that. The electrical continuity between the lugs on the CPCs and the box will be so good that I wouldn't have thought that the banjo would make any significant difference. In fact, I would have suspected that having a mixture of materials being bolted together might slightly increase the risk of the connection 'coming loose'.

Kind Regards, John

Not aimed at you Rocky.

The join between the brass gland and 'the earth' will be required [specified] to be brass or copper on many of the commercial site I've worked on and accordingly that's the standard I work to.

I've only handled the earthing nuts a few times, they can be a wonderful developement but, just like banjos, I've encountered some horrible installations with them.

 

[JohnW2]

Other than perhaps aesthetically (and the general crowding of the box, which would not be helped by any other handling of the CPC's) what is actually 'wrong' with what has been done?

Best practice is my answer.

This phrase "best practice" always seems to get wheeled out whenever people can't find an actual reason for justifying some approach (or criticising some other)

Kind Regards, John

 

[SUNRAY]

As done, each of the CPCs is bolted directly to the box. The only alternatives I can think of would be to connect the CPCs to 'something else' which, in turn, was somehow connected to the box. As I see it, that would be at least two 'connections' (between each CPC and the box), rather than just the one.

Kind Regards, John

every lug is adding a connexion.

 

[SUNRAY]

This phrase "best practice" always seems to get wheeled out whenever people can't find an actual reason for justifying some approach (or criticising some other)

Kind Regards, John

Yes I agree with that.
I also agree with your earlier comment that the 2 boxes in this installation, on the face of it, appear to be compliant with regs.
That doesn't stop it being a mess and a terrible solution in my opinion. I would only expect to find a mess like this a few years down the line after a number of alterations have been made.

 

[JohnW2]

The join between the brass gland and 'the earth' will be required [specified] to be brass or copper on many of the commercial site I've worked on and accordingly that's the standard I work to.

I don't really understand. How does the joint between a brass gland and a steel box alter in any way if one introduces a brass washer (of any sort, not necessarily a banjo) between the two? It's surely just the difference between brass>steel and brass>brass>steel?

Kind Regards, John

 

[JohnW2]

... That doesn't stop it being a mess and a terrible solution in my opinion.

It is ('aesthetically') only a 'mess' because so much is crammed into a small box. None of the proposed alternatives to the present handling of the CPCs would significantly alter that (some might even make it worse), would they?

Kind Regards, John

 

[SUNRAY]

I don't really understand. How does the joint between a brass gland and a steel box alter in any way if one introduces a brass washer (of any sort, not necessarily a banjo) between the two? It's surely just the difference between brass>steel and brass>brass>steel?

Kind Regards, John

Where is there any steel as part of the circuit when done properly?

 

[JohnW2]

every lug is adding a connexion.

That is true. However, if one thinks in the same way as those who invented the BS7671 rules about 'concealed joints', changing a crimped connection to a screwed one (if that is what is being suggested) would presumably be a retrograde step, wouldn't it?

Kind Regards, John

 

[JohnW2]

Where is there any steel as part of the circuit when done properly?

I think that this is probably at risk of getting a bit silly/theoretical/academic in the name of some sort of perceived 'best practice' (or even, maybe, 'rules').

I suppose that it would theoretically be possible for the body of the gland to be connected to CPCs with no material other than brass in the electrical path between them, but that would require that one used (unplated/uncoated) brass nut/bolt and (unplated/uncoated) brass crimp lugs (if one could find any) - but I doubt that is often (if ever!) done, even if it could be.

The really silly thing is that it is not actually the brass body of the gland with which one wants the connection but, rather, the armour of the SWA - which inevitably involves a steel/brass interface!

Kind Regards, John

 

[SUNRAY]

Well for a start I was taught [by Delta Cables] to put the banjo inside and use a brass nut on it.

I think that this is probably at risk of getting a bit silly/theoretical/academic in the name of some sort of perceived 'best practice' (or even, maybe, 'rules').

I suppose that it would theoretically be possible for the body of the gland to be connected to CPCs with no material other than brass in the electrical path between them, but that would require that one used (unplated/uncoated) brass nut/bolt and (unplated/uncoated) brass crimp lugs (if one could find any) - but I doubt that is often (if ever!) done, even if it could be.

The really silly thing is that it is not actually the brass body of the gland with which one wants the connection but, rather, the armour of the SWA - which inevitably involves a steel/brass interface!

Kind Regards, John

The lugs are supposedly tin plated which doesn't have a chemical reaction with copper or brass.

 

[JohnW2]

Well for a start I was taught [by Delta Cables] to put the banjo inside and use a brass nut on it.

OK, but I wonder how many do that? I still think that we are probably 'scraping deep barrels'!

The lugs are supposedly tin plated which doesn't have a chemical reaction with copper or brass.

OK - but, again, 'barrels' come to mind As I said before, the great weakness in these 'different materials' arguments is the inevitable (but crucial) interface between the brass gland and the steel armour that one actually wants the CPCs to be connected to!

Talking of the lugs, whatever they are plated with, what are they actually made out of. I just took a magnet to a selection and could not find one which appeared to be steel (unless stainless, which I very much doubt)?

Kind Regards, John

 

[333rocky333]

I'm not sure that I really understand the point/need for that. The electrical continuity between the lugs on the CPCs and the box will be so good that I wouldn't have thought that the banjo would make any significant difference. In fact, I would have suspected that having a mixture of materials being bolted together might slightly increase the risk of the connection 'coming loose'.

Kind Regards, John

Was referring to the Gland in the hole connection, I feel its improved by the banjo acting as a washer, for lugs i would tend to drill the box and use an independant bolt rather than the one used for the banjo

 

[333rocky333]

Talking of the lugs, whatever they are plated with, what are they actually made out of. I just took a magnet to a selection and could not find one which appeared to be steel (unless stainless, which I very much doubt)?

Kind Regards, John

Looks like copper when you cut them