Gland banjo fitting

[Amp David]

Looked at a DB yesterday and noticed that all 8 circuits were using the armour as the CPC, but the banjos at the DB end were just screwed into the steel enclosure using self drilling screws for steel. Surely this isn't correct. I have salways been shown and told that if the armour is the CPC, then the banjos must have a earth tail connected to the relevant earth bat/terminal. Each of the circuits are supplying CNC machines.

This isn't one of my jobs, as i'm just tagging along again with another spark just to get a little more commercial insight into things.

What type of fixing is best to use when fixing banjos into a steel enclosure, brass machine screws or roofing bolts. Its just i've not seen one job thats used brass fixings, ever!

 

[J@mes]

brass machine screws here!

 

[antimatter]

Do you mean Piranha earth nuts?

20mm Piranha Earth Nut - QVS Electrical Supplies | Electrical Wholesaler

 

[mechelec]

I have salways been shown and told that if the armour is the CPC, then the banjos must have a earth tail connected to the relevant earth bat/terminal. Each of the circuits are supplying CNC machines. ![/QUOTE]
It is often not possible to terminate an earth tail from each banjo due to the number of ways on the earth bar. There should be at least one from the gland plate of the enclosure to the earth bar unless the enclosure has welded/folded panels and earth continuity can be garanteed between banjos and earth bar.
What type of fixing is best to use when fixing banjos into a steel enclosure, brass machine screws or roofing bolts. Its just i've not seen one job thats used brass fixings, ever![/QUOTE]
If there is a danger of corrosion brass otherwise roofing bolts are used a lot.

 

[Amp David]

Regarding the number of ways on the earth bar, if the armour has been used solely for the cpc, then there is always going to be a spare terminal on the bar.

What concerned me about the fixing of the banjos is that no paint had been taken off around them, so only where the screw had penetrated the steel and the gland in the 20mm knockout would have been the only conductive points for the cpc of the circuits.

 

[Deleted member 26818]

Definately should have fly leads to the earth bar.
If space in the earth bar is a problem, then it is possible to link two banjos together to use one screw through both banjos and one fly lead.
Should really remove the paint to ensure conductivity anyway whether fly leads are used or not.

 

[mogga]

Banjos(fryin pans) should always be earthed either individualy or grouped Ie: daisy chained to the earth bar not nessecarliy each individual swa so long ad its continuous

 

[Amp David]

Thanks what I thought yesterday.

Thanks all.

 

[mogga]

there is a screw iv seen @ neweys "orbix" its a self tapping self drilling but IMO as per previous post bond back to bar http://orbixscrews.com/email/orbix_literature/orbix_product_guide_july2010.pdf

 

[Amp David]

The self drilling screw method just seems a little lazy, plus you're left with nasty sharp screw tips in the encloser/DB

 

[pennywise]

The self drilling screw method just seems a little lazy, plus you're left with nasty sharp screw tips in the encloser/DB

Orbix come with small rubber nipples to cover the tips of the self tappers that are protruding into the CU or trunking. Personally only use Pirana nut when doing SWA. SWA the gland company are bringing out a gland pack soon that comes with two Pirana nut included so watch out for them

 

[Amp David]

Nice one

Do the Pirahna nuts just screw onto the gland inside the encloser then?

 

[nickblake]

I must admit , i use the Orbix self drilling to fix the banjo but only if the SWA is not used as an earth , and always use a strapper from the banjo to the earth bar if the SWA is used as a cpc which is not very often only normally on remidals following a PIR the Orbix screw are fantaic ideal fo SWA cleets as you dont need to use a washer also good for fixing light fittings if youve not used them its well worth giving them a go

 

[malcolmsanford]

As would be said ..........dog rough mate

 

[pennywise]

I couldn't use the Orbix self tappers for fixing the Banjo, I like all my banjos on the inside of the CU can't stand seeing them on the outside so if I popped in an Orbix it would look slightly ridiculous sticking out of the CU

 

[nickblake]

I couldn't use the Orbix self tappers for fixing the Banjo, I like all my banjos on the inside of the CU can't stand seeing them on the outside so if I popped in an Orbix it would look slightly ridiculous sticking out of the CU

agreed if they are on the inside then fair comment , on some occasions especially with a small CU its not always easy on the inside , they do have nice yellow covers though lol

 

[pennywise]

agreed if they are on the inside then fair comment , on some occasions especially with a small CU its not always easy on the inside , they do have nice yellow covers though lol

Sorry mate wasn't trying to poo poo your method, just how I like doing them. Agreed in small CU's it can be a sodding nightmare . The little yellow nipples are quite fun

 

[nickblake]

Never thought you were mate , i do fit them inside on larger boards but got into the habit of doing it that way as i do alot of smaller boards like 2 and 4 ways , little yellow nipples as you call the work great in straws ... if you understand what im saying lol

 

[millsy82]

hi you cannot use self drilling screws into any enclosure or part of an installation eg metal trunking ,cu. They must be machine threaded.the method i was taught and used for last 12 years, 6mm nut and bolt not roofing bolts and lugged earth lead to appropriate earth terminal.NIC EIC inspector instructed me a few years ago if swa glanded connection is into a plastic enclosure you must space banjo on the inside with additional locknut giving a space bettwen banjo and plastic surface to reduce chance of heat in fault conditions. if i agree or not is a different matter.

 

[johnboy6083]

if only bolting banjos to glandplate, then IMO, you must scrape the paint away on the glandplate. you must then link the glandplate to the earth bar, again scraping paint away. Another alternative is to use serrated washers that bite into the metal. If not wanting to scrape the paint, then you must link the banjos to the earth bar. this can be done with brass nuts and bolts, or steel, and either with the banjo flat against the glandplate, or bent up.
remaber that the installation may pass testing when its brand new, bit add years of neglet and rust/corrosion, and its a different matter.

Its for this reason i try and avoid using the armopur per se.

 

[pennywise]

Nice one

Do the Pirahna nuts just screw onto the gland inside the encloser then?

sorry mate didn't see the question, the piranha nut replaces the lock nut of the gland kit one side of the nut has blades to bite into the steel enclosure.

Piranhna Earth Nuts - Pirahna

 

[millsy82]

The contact area between banjo and earth lug is sufficient if not you would not have low enough earth reading.surely scrapping paint away from cu would only speed up rust/corrosion at that point.

 

[johnboy6083]

im talking about the instance where sparks only bolt the Banjo to the glandplate, and not attach a flylead, ie ther rely on the banjo conducting through the glandplate itself.

as for corrosion, you are supposed to paint/spray the area after banjo is bolted securley, and gland is tighteneed onto glandplate. i beleive that there is a gel you can buy, its also used on connectuions from copper tinned lugs to stainless.

 

[millsy82]

The question is would a spark only bolt the banjo and not use a flying lead.but seen it done put it down to lazyness.even when using 3 core armour for earth i still gland earth flying lead at cu.
sorry for mis interpreting your post

 

[Deleted member 26818]

Not actually used these Piranhna nuts myself, just use what I'm given.
Using these, is it possible to do away with the banjo/frying pan and connect the fly lead to the nut?
The web site appears to indicate such, as they claim there is no extra drilling, but it's not 100% clear.