SWA and Plastic Boxes

[Burnt Fingers]

I'm using 1.5mm 3 core armoured cable. One of these cores is a lovely earth. However - I am terminating outside to a plastic box - new fangled pre threaded Wiska boxes, which are very nice but I have no way of securing my banjo and linking it at this end. This would leave my Steel Wires unearthed.

Am I being stupid or should I change boxes and do my normal stuff, lol.

The SWA does not run from the DB, rather from a plastic box that is fed from an undergroud supply in PVC armour, which is where I get my earth from.

I think I have my answer already but I'll post anyway whilst i find my insulin....thanks all

 

[IQ Electrical]

I'm using 1.5mm 3 core armoured cable. One of these cores is a lovely earth. However - I am terminating outside to a plastic box - new fangled pre threaded Wiska boxes, which are very nice but I have no way of securing my banjo and linking it at this end. This would leave my Steel Wires unearthed.

Am I being stupid or should I change boxes and do my normal stuff, lol.

The SWA does not run from the DB, rather from a plastic box that is fed from an undergroud supply in PVC armour, which is where I get my earth from.

I think I have my answer already but I'll post anyway whilst i find my insulin....thanks all

When using a core as a cpc the SWA must still be earthed at 1 end.

Can you use Earthing Nuts?

Earthing Nuts - Speed up metal cable gland installation and EMI / RFI screening

 

[johnboy6083]

Put the banjo on the gland before you screw it into the treated entry. Bend it and lug a 4mm g/y, and then put that through a stuffing gland into the box.

 

[telectrix]

don't you just love those earthing nuts ( or should we call them bonding nuts depending on the exact usage)?

 

[i=p/u]

well i had this problem one day where installing swa and a plastic box with rubber over the holes. i just added the gland and added into the connection block. it did seem very stupid.

 

[Burnt Fingers]

Aye - all noted and thanks to all - but I'm going to adapt my old school 4 x 4 plain boxes and use my banjos.

Worth noting cpc at one end - I'm old and possibly mad so bond at both ends, Mind you I scare easily.

I have seen bonding nuts but have not tried them - I might just keep a few though

Thanks all

 

[Deleted member 26818]

Isn't the usual method to have the banjo on the outside, drill a hole through the plastic and put the nut and bolt through the banjo and the box?

 

[Burnt Fingers]

Aha spin yes it is, but the boxes I have here need a reducer which puts a space of just too far between the banjo and the box for me to be able to bend it or spacer it and it still looks good. Oh clart......theres ny answer - use a brass bush


shoot me

repeatedly

 

[i=p/u]

bango outside in a metal box..... least i knew it needed bonded one end

 

[sjm]

Wiska make an earth bar especially for their boxes. Try this link

COMBI Junction Boxes - Bellied Box - Expanded interior space - Membrane cable entry

 

[gaulty]

Isn't the usual method to have the banjo on the outside, drill a hole through the plastic and put the nut and bolt through the banjo and the box?

If the plastic box is outside spin and you drill a hole in the box for the nut and bolt your actually compromising the IP integrity of the box. I usually put the banjo on the inside of the box and bend it down with pliers and fit my earth lug etc there.
If there is not enough room to do that in the box then I fit my banjo on the outside bend it up fit lug etc and put an IP rated stuffing gland in and pop the earth down through the gland, only thing is it's not very pleasing on the eye
That said if the armour has a core for the earth it's fine just to earth the armour at one end.

 

[telectrix]

can't see how a hole plugged with a bolt compromises the IP integrity especially if it's at the bottom. "water only flows uphill to money".

 

[gaulty]

It's not always possible to gland into the bottom of a box and what if some one drills say and 8mm hole for a 6mm nut etc, the more hole you put in a box the more chance you have of water getting in. How can you be sure that after drilling the hole that you haven't compromised the integrity? It's the same reason the fixing holes for most IP rated boxes come with seals or are separated from the main internal part of the box like the mk outdoor switch range because the holes let water in. If you can avoid it by putting the banjo on the inside why not??

 

[mogga]

well i had this problem one day where installing swa and a plastic box with rubber over the holes. i just added the gland and added into the connection block. it did seem very stupid.

I H8 those boxes with the soft crud over the holes pure crud n very soft pvc construction hard to get gland withoug gland pulling through the box

 

[telectrix]

i'm not denying that you can put the banjo inside and bend it to fit the lug, just that i can't see water getting in at the bottom. also, it's common practice to drill a small hole in the bottom to let any water OUT.