Swa Banjo?

[Ian1981]

The csa of the steele armour on a 25mm2 2core SWA equates to 60mm2 which in terms of CU eqates to 26.6mm2

You would be need the swa steel to be 136mm for it to have the same conductivity as equal to a 16mm copper equivalent

 

[Pete999]

You would be need the swa steel to be 136mm for it to have the same conductivity as equal to a 16mm copper equivalent

 

[Ian1981]

[/QUOTE
I use gn8 tables or manufacturer data for actual CSA of the steel armour but like has been said the copper-steel ratio is around 8.5 difference in conductivity so as an example if a steel conductor was used as a protective bonding conductor then the CSA of the steel would need to be 85mm to be the equivalent of the required 10mm copper

 

[Ian1981]

I use gn8 tables or manufacturer data for actual CSA of the steel armour but like has been said the copper-steel ratio is around 8.5 difference in conductivity so as an example if a steel conductor was used as a protective bonding conductor then the CSA of the steel would need to be 85mm to be the equivalent of the required 10mm copper

 

[Tes369]

I always use M6 25mm brass nuts, washer and bolts as it’s always the way I was tought and is my preference.
Piranha nuts are a great alternative, tho when using larger glands say 32 mm and up,I’ve not seen them made for this size

I don't like it when people put earthing pigtails across tray or join swa glands by a fly and leave the brass bolt long and proud. It needs tightening and cutting off with 3 threads showing so it can't catch on anything.

-It's lazy and it catches on cables when being pulled in.

Brass for me as well, reduces the risk of bi-metal corrosion and you can undo them in ten years time.

The old bi metal corrosion debate what about using brass bushes in steel conduit or trunking ...? I've never seen any corrosion.

The only time you will see corrosion is if you introduce an electrolyte salt+water.

But that would be rare.

Cheers

 

[Michaelwgroves]

I use gn8 tables or manufacturer data for actual CSA of the steel armour but like has been said the copper-steel ratio is around 8.5 difference in conductivity so as an example if a steel conductor was used as a protective bonding conductor then the CSA of the steel would need to be 85mm to be the equivalent of the required 10mm copper

This is also covered in Guidance Note 8 Earthing & Bonding 5.2.1 pg 60.
I think it's also covered generally in Guidance Note 1, selection and Erection. I think the statement used is generally you should not use SWA for main protective bonding, but I can't recall which section this was.

 

[bonjovi]

is this question real really , as most on hear know the armourings are used as protection for the cable which is usually used when its installed in areas likely to get mechanically damaged ,ie buried ,spade digging ,and secondly a lot of sparks still use this as a cpc to keep the cost down and not include a extra core as a earth , either way the armourings need to be earthed, this is done via a gland , banjo nut and bolt for a solid earth and flylead . its beggers belief to think there are guys out there doing work not knowing such a thing

 

[Pete999]

is this question real really , as most on hear know the armourings are used as protection for the cable which is usually used when its installed in areas likely to get mechanically damaged ,ie buried ,spade digging ,and secondly a lot of sparks still use this as a cpc to keep the cost down and not include a extra core as a earth , either way the armourings need to be earthed, this is done via a gland , banjo nut and bolt for a solid earth and flylead . its beggers belief to think there are guys out there doing work not knowing such a thing

 

[telectrix]

i always use a banjo:

OK it's a UKelele. thank God it's no longer an EUelele.

 

[Ib≤In≤Iz]

I mostly use piranha nuts now, much better and neater than a banjo. Brass for me too and always a fly lead to the earth bar.

 

[SJD]

It has the banjo fitted so it must be fine!!!
What on earth did they manage to do to that gland to rip off the end of the clamp nut?

I finally started the remedial work on these glands (4 in total), the original installer had bought size 20 glands when the cable needed size 25. The badly damaged one, it looks like they'd had a go at trying to get the armour inside but given up after damaging the gland. The other three, they'd just snipped it all off.

 

[soms]

Without having my books to hand, having not (yet) been taught this and calling on the years of valuable experience available here, how does one select the CSA of the fly-lead?
Should it follow the usual rules for sizing CPCs - either be the same CSA as the live conductors or be selected by calculation using the adiabatic equation?
Surely unless it is correctly sized it may also prove unreliable under fault conditions?

 

[Ian1981]

Without having my books to hand, having not (yet) been taught this and calling on the years of valuable experience available here, how does one select the CSA of the fly-lead?
Should it follow the usual rules for sizing CPCs - either be the same CSA as the live conductors or be selected by calculation using the adiabatic equation?
Surely unless it is correctly sized it may also prove unreliable under fault conditions?

If you are utilising the armour as the circuit cpc then yes I would use the Adiabatic or the tables and size the fly lead accordingly.
If I am just earthing it and using a core within the cable as my cpc then I will use a minimum of 2.5mm for the fly lead , if mechanical protection is not necessary.
Depending if we are dealing with larger swa cables where the fault current is likely to be higher and more severe then I would install a larger fly lead put probably nothing larger than 10mm

 

[Tes369]

Without having my books to hand, having not (yet) been taught this and calling on the years of valuable experience available here, how does one select the CSA of the fly-lead?
Should it follow the usual rules for sizing CPCs - either be the same CSA as the live conductors or be selected by calculation using the adiabatic equation?
Surely unless it is correctly sized it may also prove unreliable under fault conditions?

Generally you don't somebody on more money than you does who drives a nicer car than you.


On a glaxco chemical plant I was on recently all the earthing flies were 6mm.

There was a big debate going on because EX SWA glands the sheath were left off because not required. They liked it in the end as no armour showing anyway.

Lots of earthing going on if the pipes resistance was greater than 10 ohms across the flange then flies were put between the flanges on pipes.

The Electrical engineer in the office had the final say on what went down with his brand new Audi in the car park to prove it.

 

[Pete E]

I use these when terminating into a plastic box. Great way to maintain earth continuity

View attachment 41521

Just curious what they are called?

 

[123]

Just curious what they are called?

It's a Wiska EMC Earth Clamp

 

[Pete E]

Thanks, much appreciated!

 

[timbobelfast]

Generally you don't somebody on more money than you does who drives a nicer car than you.


On a glaxco chemical plant I was on recently all the earthing flies were 6mm.

There was a big debate going on because EX SWA glands the sheath were left off because not required. They liked it in the end as no armour showing anyway.

Lots of earthing going on if the pipes resistance was greater than 10 ohms across the flange then flies were put between the flanges on pipes.

The Electrical engineer in the office had the final say on what went down with his brand new Audi in the car park to prove it.

6mm is the norm for all Petro-chemical sites, hope they used copper tube lugs rather than the crappy yellow lugs the fail in no time!

 

[Tes369]

6mm is the norm for all Petro-chemical sites, hope they used copper tube lugs rather than the crappy yellow lugs the fail in no time!

There was some really nice Pyro work on that job and the new EX rated emergency stop buttons were a fraction of the size of the original equipment ex emergency buttons. And I bet they last a fraction as long as well.

All the old gear had "Made In Great Britain" on it

 

[telectrix]

i've got made in britain stamped across my navel. ain't done me any favours.