Earthing SWA Armour at Point A or B?

[Darkness]

I am taking power from and outbuilding Point A to another building Point B. I just wanted to check with you guys if its ok to earth the armour at Point B because I have no room or good spot at Point A to fit a metal box so I was maybe planning to fit the metal box at Point B instead and earth it there.

The only problem I can think of is if ever the earth core of the swa was terminated at Point A, the armour would not be earthed from Point B.


Cheers.

 

[Spark123]

I take it you have 3c and are using the additional core as the CPC, then back feeding the earth to the armour?
It isn't a massive sin providing EFLI values are met, however I'd prefer to see it earthed at source. Can you use a piranha locknut?

 

[ban-all-sheds]

Why do you think you need a metal box at Point A?

What are you mounting the gland on at point A?

 

[VanSolo]

You don't need that much room to earth an swa gland,
even in a small plastic box

Untitled

• VanSolo
• 9 Oct 2009
• 1

 

[holmslaw]

..

 

[Click-Sure]

Earthed metallic armour must be earthed at source, period.

 

[Spark123]

You don't need that much room to earth an swa gland,
even in a small plastic box

Untitled

• VanSolo
• 9 Oct 2009
• 1

Would have been better with pirahnas or locknut, banjo, locknut. Hate seeing banjo's tightened against plastic.

 

[holmslaw]

..

 

[electronicsuk]

What a lash up!

I think that's a bit unfair.

The box is too small.

Says what regulation? All the wiring looks to fit in there.

The box should be galv steel.

Says what regulation?

The cable should enter the bottom surface.

Says what regulation?

Banjo rings should be fitted to the brass face of glands, not a galv lock nut.

Agree with this one, but again, not sure there's a regulation that forbids it. As long as the connection is sound and EFLI within limits, it shouldn't be a problem.

The swa and cable core earths should be connected together.

It would seem sensible, but they don't have to be.

 

[Spark123]

Banjo rings should be fitted to the brass face of glands, not a galv lock nut.

Agree with this one, but again, not sure there's a regulation that forbids it. As long as the connection is sound and EFLI within limits, it shouldn't be a problem.

I wouldn't class metal against plastic a sound electrical connection.

 

[ban-all-sheds]

Matthew - I'm as dubious as you on most of that list of "faults", but I think that having to bend the banjos shows that the box is too small for that type of fitting, and I'm not sure how tight it will all stay over time, and if it does work loose then those bent banjos will make it hard to re-tighten.

Spark - it's only metal against plastic on one side, and the armour is not being used as the cpc...

 

[electronicsuk]

Banjo rings should be fitted to the brass face of glands, not a galv lock nut.

Agree with this one, but again, not sure there's a regulation that forbids it. As long as the connection is sound and EFLI within limits, it shouldn't be a problem.

I wouldn't class metal against plastic a sound electrical connection.

I guess this is where my opinion differs. If it were me carrying out the work, I would have used piranha nuts with the plastic enclosure, or a galv through box as suggested by Holmslaw. However, I would simply consider that good workmanship. If a banjo'd gland is done up tight on a plastic enclosure, it should not work loose by itself. Granted it wont be as secure as glanding onto a metal enclosure, especially if there's mechanical stress on the cable and gland, but then we're into external influences.

 

[Spark123]

You say it shouldn't become loose but they can and do.

 

[ban-all-sheds]

It's outside - brass, steel and plastic all expand and contract at different rates.

It'll probably work loose.

 

[VanSolo]

Ok so it's not a perfect example, but even with an extra brass locknut or piranha nut the swa could be earthed in a small space and that was what I was trying to show.
I agree that the box is small but everything fits ok.
It is actually indoors on a warehouse wall so glands entering the sides and exposure to the elements not an issue.
EFLI was ok as were all other tests.
Not my own work, photo taken during a pir as I had not seen two swa cables joined in this way in a small plastic box and apart from some minor workmanship issues it works.
Couldn't code it, you chaps got any ideas? (not 134.1.1)