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