Use/purpose of Gland when installing garage consumer unit

[ban-all-sheds]

I wonder if we've got the old diameter / cross-section confusion again?

Judging by the photos, I'd say yes, we have.

A confusion not helped, I have to say, by so many of the regulars here not bothering to type mm² when providing information to people....

 

[benjiman]

Oh righty! nice one cheers.

Also in the picture below I have put the steel through the hat. And the black sheath butts up to the hat. Is this right or do I want the whole black sheath including the steel to go inside the hat.

Then have only a little steel exposed that goes into the olive?

Cheers.

 

[plugwash]

normal practice is to do it so that the plastic bit goes over the cable sheath

 

[benjiman]

I wonder if we've got the old diameter / cross-section confusion again?

Judging by the photos, I'd say yes, we have.

A confusion not helped, I have to say, by so many of the regulars here not bothering to type mm² when providing information to people....

sorry chaps. The SWa is 16mm in diameter. I think i said that right. Measured lenght from the middle across.

 

[benjiman]

normal practice is to do it so that the plastic bit goes over the cable sheath

is there a recommended size for the lenght of the steel to be?

Or do you just measure so it takes it approximately in the olive section?

Also just to clarrify. Does the SWA go into the hat or not? Ive done it so the outer sheath of the SWA butts on the hat. And the steel goes in. Hence in the picture I have alot of steel. Is that correct?

if the whole Swa need to go into the hat i will then need to snip some more of the hat so the whole of the swa including outter sheath goes into the hat.

 

[HDRW]

normal practice is to do it so that the plastic bit goes over the cable sheath

is there a recommended size for the lenght of the steel to be?

Or do you just measure so it takes it approximately in the olive section?

Yes, it should be the length needed to go into the olive, and the bottom of the nut should be over the sheath. It means you want about an inch of steel showing (but measure it, don't take my word for this!).

Also just to clarrify. Does the SWA go into the hat or not?

Yes, the hat should seal over the sheath to make it watertight (or as much as possible!). If you think about it, if the steel sticks out beyond the hat, moisture can (a) corrode the steel (b) creep up between the steel wires, to the inside of the hat in one direction and down the cable in the other. This is a Bad Thing

Ive done it so the outer sheath of the SWA butts on the hat. And the steel goes in. Hence in the picture I have alot of steel. Is that correct?

No, butting it isn't good enough - the hat should cover everything (including the nut when it's all installed and the hat is pushed up to the box you're going into).

if the whole Swa need to go into the hat i will then need to snip some more of the hat so the whole of the swa including outter sheath goes into the hat.

Fair enough!

Cheers,

Howard

 

[mapj1]

Ha! I knew i'd missed something off. Those are the fittings of the type without an olive.
Silde the hat way down the wire so its out the way, but only slitting the bit youve trimmed, so its as snug as possible. Cut the steel to be a little longer thn the rough section on the brass body (or if doing the dirty, all strands bar a few, which are left with the central cores - I don't recommend that, but some people like to create an extra earth tail that way..) .
Thread on the back nut, hedgehog out the short steels, and fit the body, such that the steel ends are trapped between the nut and the body, but the cores go through the body..
Taking care not to get it cross- threaded, fit the nut to the body so as to tighten the fitting to pinch the steels tightly. if need be remove, re-trim the steel ends and repeat, until it is clamping tightly but evanly (not riding high on one or two twisted strands)
Hope that helps

 

[benjiman]

ahaa!!

Thank you very much everybody for your help.

Snipped the hat and now the whole swa goes in. Pushed the hat back and now trying to tighten it.

HOWEVER ive hit a new problem. I though mapj1 was kidding when he said that tighening the thing up is really difficult.

HOW WRONG WAS I??!

Ive tried everything to get the olive to tighten onto the steel. But its not having it! Any tips on tighening it up?

Its really difficult cos you have to pull the inner sheath in so that there no gap between the olive and the inner sheath.

 

[mapj1]

It may help to massage the cut steel strands into lieing down onto the rough section of the brass body.- if they got a bit chewed when you cut them then straightenting with long nosed pliers maybe is in order. (or even a nip with a pair of plumbing pliers with a pipe section, but don't squash e the brass body out of round !) Make sure they do not rise high enough to foul the threads of the nut- having them a bit longer than needed and a hint of steel showing once the nut is tighted is usually considered OK, but no more than perhaps a cm.

http://www.focal-point.co.za/ccg/glandsandboxes/bw.htm
Shows almost the style of gland you have, though not the clearest which is body and which is nut..

 

[benjiman]

hi map, thanks for the reply.

I have tried what you said to no avail. Do you think I have got faulty glands?

Ive been through two on a practive run and the nuts have become chewed up from the attempt and slipping from the force ive been putting on them.

Its looks impossible to tighten. Is it possible for an average person to tighten it? Or do you need some specail skills and equipment.

Im using an adjustable spanner to tigthen and a crimping plier to hold the other nut. Buts its just not having it. Surely they cant have made the gland so you need to be a genius to tighten it?!

This is getting ridiculous now. The glands were bought a few years back. Could this be why they arent tighening? They were packed however.

 

[pdcelec]

Are the glands the correct size for the cable?

 

[benjiman]

the cable is 16mm in diameter swa. The writing on the glands package says BW 20s.

An old electrican mate bought them with the SWA years back. So i assumed they were correct ones.

The olive bit slides onto the steel strands fairly easily. It doesnt slide over the inner sheath.

I can feel the friction between the olive and the steel strands. So it is fairly tigh i think. So all I need is for the olive to tighten slightly and it should in theory grip the steel. But its definately not happening!

 

[pdcelec]

put photo of what you have got on here. Helpmay still be possible

 

[David E]

Do you think I have got faulty glands?

If you think you have faulty glands maybe you should see a doctor!!!!!!!

 

[securespark]

Yes, the hat should seal over the sheath to make it watertight (or as much as possible!). If you think about it, if the steel sticks out beyond the hat, moisture can (a) corrode the steel (b) creep up between the steel wires, to the inside of the hat in one direction and down the cable in the other. This is a Bad Thing

If you want protection from moisture, you should be using CW, not BW glands.

BW glands do not give "watertight" protection to the install, and are only suitable for internal situations.

If your gland is not gripping the armour, then either it is not tight enough or the gland is the wrong size. Being a 20s, it is the smallest, so I think this is not the problem. Either you have crossed threads, or it is not tight enough. Usually, the nut goes almost right up to the gland body when fully tight.