Final check regarding SWA glands

Discussion in 'Electricians' Talk' started by Pete, Dec 14, 2004.

  1. Pete

    Pete Guest

    Afternoon,

    I’ve had a good search of these forums regarding the terminating of SWA armoured cabling using glands. I think I’ve got the idea now, but as one last check Id like to run my conclusions by you all here.

    Just a bit of history on the installation: I’ve installed a lighting and power circuit in my out buildings. This consists of x2 13 amp sockets (2.5mm2 cable) and x3 60 watt bulkhead lights and a halogen spot (1.5mm2 cable). These terminate in an RCD equipped garage consumer unit, with a 6a and a 16a fuses (lights and power respectively).

    All I need to do now do is run the armoured cable from the house to the garage. I intend to use 6mm2 SWA cable. I understand that this needs to be terminated in junction boxes prior to running into the garage and house consumer unit.

    From what I have read on these forums, I know have two options:
    1) Use the armour as the earth
    2) Use 3 core instead.

    I would appreciate some advice.

    If I use three core I assume I do not need to use the supplied banjos with the gland kits?
    In the junction boxes I have fitted 32a rated porcelain chock blocks, is this the correct way to provide the cross over from the SWA to the standard cable?
    Even if I use 3 core, do I need to earth the cable Gland?
    I would appreciate if someone could point me in the direction of a good picture that explains how to fit a glad. I’ve read some good descriptions on here, but I am still a bit confused as to how the armour is connected to the gland/banjo.

    Thanks for any help you can give, it will be much appreciated.

    Cheers

    Pete
  2. opentoideas

    opentoideas New Member

    Hi Pete,

    i may have read this wrong but i get the impression that you were sugesting that if you used 3 core then you were NOT going to use a gland and therefore NOT earth the armour.

    this is very wrong (sorry if this is not what you meant) the armour MUST be earthed as if something cuts the cable then it will have to go through the armour first and when a live is encountered the current should be earthed back through the armour causing a large fault current and tripping the circuit.

    as for the glands the best way i can describe them is like those quick connect hose connectors, just imagine the armour is the hose! it is a pain to get the armour in but then the armour does still provide a degree of mechanical protection right up to the gland.
  3. Pete

    Pete Guest

    Thanks for the reply. I would not have eartherd the armour without your advice. I guess I just earth the the arrmour into the earth terminal on the choc block along with the earth core of the armoured cable

    ie


    L armoured ---->L terminal---> L Standard Cable
    N Armoured ---->N terminal---> N Standard Cable
    E armoured ---->E terminal---> E Standard Cable
    Cable Armour--------^

    Cheers for you help
  4. Addie

    Addie New Member

    why use junction boxes I would gland straight into the consumer unit
    If a plastic consumer unit use the supplied banjos and link a earth wire from the banjo to the earth terminal in the consumer unit
  5. The Trician

    The Trician New Member

    You'll be lucky to get away with doing that! Most plastic CUs wuoldn't support the ***** off a chocolate mouse, never mind having an SWA gland tightened onto them.

    You should terminate the SWA into an adaptable box, then come out of the box and into the CU with twin and earth.

    You should fit the earth tags beneath the locknuts and run single earth wires from these tags to the earthing terminal in the CU.

    Do it right!

    TT
  6. Pete

    Pete Guest

    Thanks for all the advice, you have all been very helpful.

    I know exactly what I have to do now. I 'm going to take the advice and use the armour as the earth .

    What I have is this set up

    Garage CU<--(twin and earth)<---Junction box<---(armoured cable)<--Junction Box<--(twin and earth)<---House CU

    Rather than run the armoured cable earth all the way to the two CU's. I guess I can use the choc block in the junction boxes, to cross over to the earth in the standard cable?

    Any thoughts on the use of the porcerlin choc blocks as opposed toht eplastic ones.

    Thanks Agian for your help
  7. Jonny

    Jonny New Member

    Using adaptable boxes is fine. You may find it easier to position these on the outside of the building, so you have T&E running through the wall into the rear of the box, and the SWA gland out the bottom. This also gets round any problems with the large bending radius when trying to bend a vertical run from underground at right angles through the wall.

    Thought the porcelain ones are only low current, designed for downlighters? Plastic are fine.
  8. biglad65

    biglad65 Member

    hi can anyone please tell me if 6mm swa wire is ok to run 30mtr from house to garage to run 3x 13amp with 2.5 wired sockets and 2x 60wat bulbs with 1.5 wired lights or do i need 10mm swa.

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