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Why in the name of god would you use banjos on a metal gland plate?

What purpose would they serve?

The transformer glands are quite adequately earth via the aluminium plate so no need for banjos, the switchgear end is in to an insulated gland plate. Having an earth at both ends would cause circulating currents.

I await your answer with interest.

Read the thread, I already have, it's only what you and the other guy are concluding and suggesting that's what I'm thinking.
 
the glands would have come with them and I'd have fitted them, personal preference or just habit I suppose.
.

But to what end? What would be the advantage of fitting them?
It's like glanding an SWA onto galvanised trunking, you wouldn't fit a banjo then would you?

Doing something because it is just habit suggests a lack of thought or understanding of the job in hand.
 
But to what end? What would be the advantage of fitting them?
It's like glanding an SWA onto galvanised trunking, you wouldn't fit a banjo then would you?

Doing something because it is just habit suggests a lack of thought or understanding of the job in hand.
depends.

i would fit banjos on galv trunking because the connections are din rail connectors in our panels and there is no earth bar so
 
I'm not suggesting anything.
the glands would have come with them and I'd have fitted them, personal preference or just habit I suppose.
Neat job, Heat shrink would have finished it off nicely.

All I can say is you wouldn’t be on a job with me for very long. Personal preference or force of habit aren’t logical reasons for doing something.

The only time I would run a copper tape jumper between each “gland” was for PILC sweated in to wiping cones. The simple reason being there is a cork gasket between the cone and the box. This would only be done at the transformer end as at the switchgear end they were insulated from each other to stop circulating currents.

Someone else has mentioned the lugs being strained to get them aligned with the terminals. The reason I would reverse the orientation of the lug as shown in the drawing above.

Cleating singles is a subject of it’s own, there are good safety reasons for doing it.
 
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Looking closely at the first picture I would say the lugs aren't so much misaligned as being the wrong design for the terminal. The reason they are bent is that the shoulder where the palm is joined to the tube is in the way.
 
It's like glanding an SWA onto galvanised trunking, you wouldn't fit a banjo then would you?

It depends, If I am using the SWA as the earth or I cant banjo it the other end of the cable for some reason then I will banjo it to the galv trunking.
I have always been of the opinion that even if you dont technically need it if it is there why not fit it?
Unless of course it means running in 20m of earth single or it would look stupid or out of place but thats a different kettle of fish.
 
It depends, If I am using the SWA as the earth or I cant banjo it the other end of the cable for some reason then I will banjo it to the galv trunking.
I have always been of the opinion that even if you dont technically need it if it is there why not fit it?
Unless of course it means running in 20m of earth single or it would look stupid or out of place but thats a different kettle of fish.

I don't get it, if you drill teh hole the right size and tighten the locknut properly then that makes a good metal to metal connection so why the banjo?
And what do you do with the banjo, just stick a bolt through it to hold it to the trunking?
 
Nope, I put a bolt through with a crimped wire attached and run to the nearest earth point.
Doesn't everyone?? :s

The purpose being to ensure it is earthed correctly.
After all you are assuming that the trunking is correctly earthed, which from my experience its not!
 
But the trunking is your CPC, why on earth would it not be earthed?

Why would you install a seperate earth wire inside the trunking which has a csa a few orders of magnitude bigger?
 
I was always taught its good practice.

Just to play devils advocate if you were to install a armoured into a galv trunking do you go and check that every screw and bond is in place? Can you guarantee that nobody has come along and modified it, removed a link? Hell I have seen a few that were not bonded at all!

Like I said for the sake of drilling a 6mm hole (which is the size of a pilot drill for most hole saws) and putting a bolt and crimp on whats the harm?

I agree they are not really needed normally but I can say its there.
Ime sure there used to be a reg that said a SWA had to be banjo's at least one side anyway?
 
If it is existing trunking and it is not in acceptable condition then I would not be glanding an SWA onto it my installation would not be compliant.
Steel trunking must be effectively earthed in its entirety, if it is not then it does not comply.
 
Ok I will give you a prime example,

I did some work in a office, The desks had a 2x4 Metal powder coated galv compartment trunking drop to each row going under them, They were fed from a SWA fed from a board half way down the office.

So I linked out each section with a link. So where was I meant to earth it?
I could rely on just the 6mm crimped lugs screwed to each section of the trunking and wired into a socket, But I would rather Banjo the gland as well just to be on the safe side.

At the end of the day I would rather put that extra earth path in as its a doddle to do and doesnt take me any more significant time.
If you dont want to I wont hold it against you :p
 
Powder coated trunking is a little different, I would be looking at an additional connection to the gland, the same as with a painted surface.
I would use an earth nut or a CMP ciel type gland for preference over a banjo.

My earlier comments have all been about bare metal, apologies if that was not clear.

To be honest I prefer to screw the gland in to a flange coupler and attach that to the trunking with a serrated washer than just attaching the gland straight to the trunking anyways.
 
Yeah new ones are pretty crap.
I found a stash of old ones the other day in a drawer though so I have been using them the last few weeks.
You can even get a spanner on em!!
Why dont they make em like they used to :(
 
Got to say an earth tag does have a greater contact area than a gland /l.nut, the larger size tags 50-63-75 are rated at 10.40ka fault current so when the cables armour can exceed that value and there is a possibility that it might have to a gland with an integral earth boss should be used ,so the idea that the gland / termination doesn,t need earthing and that the trunking / gland plate is acceptable needs to be checked out.Can,t find the ka rating of glands though.
 
Got to say an earth tag does have a greater contact area than a gland /l.nut, the larger size tags 50-63-75 are rated at 10.40ka fault current so when the cables armour can exceed that value and there is a possibility that it might have to a gland with an integral earth boss should be used ,so the idea that the gland / termination doesn,t need earthing and that the trunking / gland plate is acceptable needs to be checked out.Can,t find the ka rating of glands though.

So where is that going to help when the fault level at the transformer is liable to be around 25KA?
 
Think the argument is 50/50 about the clamping the cables down although it gives that professional finish but must agree with everyone else ... heat shrink a must - tape is rough and you rely on the tape gum for the life span of the equipment although it poses not real safety risk a few yrs down the line your tape could be pealing and giving your work a poor reputation to anyone that follows you. Having said that if all your been pulled for is lack of heat shrink and a debatable lack of fixing then I wouldn't fret too much and take the advice on board.


Just spotted this post DW.

The jury has returned with a verdict. Have a look elsewhere for a topic on transformer tails. In particular the bit about magnetic reaction under fault conditions. It’s not a case of they look better, it’s a matter of safety.
 

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