SWA cables - fly leading armour as cpc??

[snipersmith87]

Just after A bit of advice regarding a load of swa cables into dist board. What's people's preferred methods / good practice regarding banjos fly leads etc. Banjos inside?? If multiple cables are using armour as cpc is it considered bad practice to use 1 fly lead between the two Banjos??? Is it worth fly leading just to earth armour when not cpc or just rely on metal enclosure of db???? Got quite a few and want a tidy job

 

[Spoon]

There is nothing wrong with using the metal enclosure of the board. Also nothing wrong with using the armour as cpc, as long as it is suitable.

 

[snipersmith87]

Appreciate the reply spoon. I understand there's nothing wrong with using the armour as cpc. However when using armour as cpc is it considered good practice to fly lead. Testing purposes??? What about 2 banjos from separate cables with one fly lead???

 

[buzzlightyear]

1 fly lead between the two Banjos???

??????????????????????

 

[ipf]

Try these.......

 

[Leesparkykent]

If the armour is used as the CPC then you have no option other than to fly lead. I like the piranha nuts personally.

 

[Strima]

The fly lead must satisfy the adeabatic equation if using the armour as a CPC.

 

[Spud28]

As ipf's post much easier to use than banjos

 

[Spoon]

Appreciate the reply spoon. I understand there's nothing wrong with using the armour as cpc. However when using armour as cpc is it considered good practice to fly lead. Testing purposes??? What about 2 banjos from separate cables with one fly lead???

Something like this will be good.

 

[Pete999]

Appreciate the reply spoon. I understand there's nothing wrong with using the armour as cpc. However when using armour as cpc is it considered good practice to fly lead. Testing purposes??? What about 2 banjos from separate cables with one fly lead???

If you do that you will more than likely be cutting the csa of the cpc, two circuits sharing 1 cpc not good practice I would think, why not use PIRANHNA locknuts instead of banjos?
Piranhna Earth Nuts - Pirahna - https://www.tlc-direct.co.uk/Main_Index/Earthing_Index/Piranhna_Earth_Nuts/index.html
Much easier than flaffing about with Banjos IMHO

 

[Darkwood]

Using the enclosure alone without flyleads can be bad depending on the construct of the enclosure/board, if you are terminating to a removable gland plate of a any metal that is not a solid part of the construct then a fly lead is needed as you will be relying on the (usually) self tappers that affix the plate to the rest of the box and you cannot say for sure if these screw which are usually paint on paint contacts will carry a fault current.
(There is nothing wrong with looping fly leads as long as its CSA can serve the largest circuit.)
This is why you don't need a banjo on metal conduit through boxes because they are a complete solid mold yet most gland plates would require them to ensure good earth fault return.
I would also add that even when glanding to solid constructs then without a flylead you have to ensure good contact and not poor contact to paint, IE using robust serrated washers or removing the paint prior to termination.

 

[snipersmith87]

[QUOTE="buzzlightyear, post:
2 separate banjos sharing same nut and bolt. Drilling 1 hole.

 

[snipersmith87]

If you do that you will more than likely be cutting the csa of the cpc, two circuits sharing 1 cpc not good practice I would think, why not use PIRANA locknuts instead of banjos?
Piranhna Earth Nuts - Pirahna - https://www.tlc-direct.co.uk/Main_Index/Earthing_Index/Piranhna_Earth_Nuts/index.html

I thought it may be considered bad practice. Only thing confusing me is if we can use metal enclosure as satisfactory earth path through gland alone surely a fly lead regardless of it being 1 per 2 banjos is even better??? Another path to earth???

 

[Pete999]

I thought it may be considered bad practice. Only thing confusing me is if we can use metal enclosure as satisfactory earth path through gland alone surely a fly lead regardless of it being 1 per 2 banjos is even better??? Another path to earth???

Some of the SWA glanding jobs I have seen wont give much continuity to earth, nuts not tightened properly, enclsure not prepared correctly.

 

[snipersmith87]

See I've always seen fly leading any armoured at supply end cpc or not as best practice. However Ive came to wonder if im wasting time as I seem to be coming across more and more sparks who don't bother with it....... "It's connected to a metal board"

 

[Pete999]

See I've always seen fly leading any armoured at supply end cpc or not as best practice. However Ive came to wonder if im wasting time as I seem to be coming across more and more sparks who don't bother with it....... "It's connected to a metal board"

Yes but has the connection between the enclosure and the SWA been done correctly? they don't teach this sort of thing in the training outfits do they, make an end off job done.

 

[snipersmith87]

Using the enclosure alone without flyleads can be bad depending on the construct of the enclosure/board, if you are terminating to a removable gland plate of a any metal that is not a solid part of the construct then a fly lead is needed as you will be relying on the (usually) self tappers that affix the plate to the rest of the box and you cannot say for sure if these screw which are usually paint on paint contacts will carry a fault current.
(There is nothing wrong with looping fly leads as long as its CSA can serve the largest circuit.)
This is why you don't need a banjo on metal conduit through boxes because they are a complete solid mold yet most gland plates would require them to ensure good earth fault return.
I would also add that even when glanding to solid constructs then without a flylead you have to ensure good contact and not poor contact to paint, IE using robust serrated washers or removing the paint prior to termination.

Are you saying just loop between the banjos to earth bar darkwood??? Aslong as biggest cpc size??

 

[Darkwood]

Yes, if you think about it that is what the earth bar is itself, you're just bringing that setup forward to the glands. I do it often, it is a lot neater than having 10+ flyleads to have one and several neat loops, it also means you can double/triple etc the banjo's to one bolt hole allowing both neater appearance and more glands per given space.

 

[snipersmith87]

Yes, if you think about it that is what the earth bar is itself, you're just bringing that setup forward to the glands. I do it often, it is a lot neater than having 10+ flyleads to have one and several neat loops, it also means you can double/triple etc the banjo's to one bolt hole allowing both neater appearance and more glands per given space.

I think I'm gonna go with this idea. Be much neater. Do you only link to earth armours and then separate fly leads for each armour acting as the cpc??? This is what I was aiming for by using more than one banjo per bolt/link.

 

[Darkwood]

I think I'm gonna go with this idea. Be much neater. Do you only link to earth armours and then separate fly leads for each armour acting as the cpc??? This is what I was aiming for by using more than one banjo per bolt/link.

It makes no difference the fact is the armour requires earthing so its makes no difference if the SWA is the earth or just been earthed, the method I describe is normal practice as long as you size you cpc fly-lead correctly to the largest circuit if looping.