Discuss Terminating SWA Cable. in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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I wounder if anyone would be so kind as to offer some advice. It's not something I'm actually wiring up, it's just a little theory project to do with college.

If I want to come from a breaker switch in a distribution board, and run a supply along a cable tray in SWA cable to a 32amp three phase and earth interlocked socket. From looking in tables I have figured I'm going to need to use 4.0mm SWA cable and obviously I'm going to have to terminate the cable at each end using glands. What I'm not sure about is how many core cable should I use, as should I use the outer steel wires of the cable as the CPC Earth), which would mean I could use 4 core cable, or should I use 5 core cable, and one of the cores of the cable as the CPC as well as connecting the outer steel wire sheath to earth?

The other thing I'm not too sure about, if I can use the outer of the cable as CPC, when I terminate it to the interlocked socket, this has a plastic housing. Would I therefore use one of those washers around the gland with a the little bit that sticks out and make a connection to this and then take this in to the earth terminal?

Thanks for any advice offered

David
 
id personally go for a 5 core, although its all about personal preference and also the calculaion to make sure the armouring is sufficient for acting as cpc. thats why id stick to a designated earth core.

you should always use the "banjo" on the swa gland and connect from this to the cpc of the circuit at both ends of the cable.
 
Run a seperate Earth

Of course, you'd only run a seperate earth if it was a distribution circuit.
Not a final circuit ;)

...Thing is though you don't always run a seperate earth with a distribution circuit either, you would if it was a 2 core swa mind.

Hope this has helped some?

Night all!
 
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Thanks for your help on this one guys.

I got it figured now. Use on of the conductors in the cable as the CPC / earth, and at each end of the cable where I'd terminate it in a gland, make sure I've got the banjo washer on here, then make connections to the CPC / earth. So, instead of using the steel wire part of the cable as the CPC / earth, what I am in effect doing is bonding it the the CPC / earth.

I don't know if it's me being a bit dim here, coz it wouldn't be the first time, but I'm a little confused by what Bane said:

Of course, you'd only run a seperate earth if it was a distribution circuit.
Not a final circuit
Terminating SWA Cable. {filename} | ElectriciansForums.net


...Thing is though you don't always run a seperate earth with a distribution circuit either, you would if it was a 2 core swa mind.

Any chance of a for example on that one mate??? - I'm only a first year apprentice at this electrickary lark!

David
 
if you were installing a 2 core SWA to whatever (consumer unit or whatever) then you would probably run a seperate earth along with it, rather than relying on the armouring as the earth. obviously if you run a 3 core with a earth as one of the cores you wouldn run a seperate earth.

alot of this is personal preference and some folk will use the armouring as the earth. there is nothing wrong with it so long as the necessay calcultions are made to establish it is satisfactory.

imho its better to run a seperate earth but thats just my opinion

rich
 
Comment removed. He's an apprentice, year 1 of course he doesn't know Trev.
Now stop grumping you miserable old git:)
 
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There must be something going on with my browser. It keeps dragging up old things. The other day it was Gary Mason dying which was a year ago nearly, now this.
 
the outer steel wire can be used as the CPC using the banjo's and fly leads to provide termination at the earthing terminal. it would normaly only need to be earthed at one end of the cable but both in this case. there is a table available which proves the outer sheath can be used as the CPC. in any case the sheath and any unused conductor in a multi core cable needs to be earthed.

as its a project ensure that ALL the main bonding is in place before any works are carried out.
 
There must be something going on with my browser. It keeps dragging up old things. The other day it was Gary Mason dying which was a year ago nearly, now this.

Thought it was just me things like that happened to lol. Another 1 I keep getting is when i'm in the middle of reading a topic I get a warning that leaving the topic will delete any stuff in the editor, or words to that effect. Drives me B****y crazy. (Go on say it, i'm already there:rolleyes2:).
 
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Thought it was just me things like that happened to lol. Another 1 I keep getting is when i'm in the middle of reading a topic I get a warning that leaving the topic will delete any stuff in the editor, or words to that effect. Drives me B****y crazy. (Go on say it, i'm already there:rolleyes2:).


You must be using google chrome then.:sailor:
 
I wounder if anyone would be so kind as to offer some advice. It's not something I'm actually wiring up, it's just a little theory project to do with college.

If I want to come from a breaker switch in a distribution board, and run a supply along a cable tray in SWA cable to a 32amp three phase and earth interlocked socket. From looking in tables I have figured I'm going to need to use 4.0mm SWA cable and obviously I'm going to have to terminate the cable at each end using glands. What I'm not sure about is how many core cable should I use, as should I use the outer steel wires of the cable as the CPC Earth), which would mean I could use 4 core cable, or should I use 5 core cable, and one of the cores of the cable as the CPC as well as connecting the outer steel wire sheath to earth?

The other thing I'm not too sure about, if I can use the outer of the cable as CPC, when I terminate it to the interlocked socket, this has a plastic housing. Would I therefore use one of those washers around the gland with a the little bit that sticks out and make a connection to this and then take this in to the earth terminal?

Thanks for any advice offered

David

Hello David

Yes use earthing washers at the end of steel wire armour cables, fix the earth wire to them using either a crimped on yellow eyelet terminal (tag/crimp connector) and use a suitable bolt (copper if possible as some people don't like roofing bolts to be used for this)or if none available/practical to get in reasonable timescale, twist the wire round the eyelet and then set it with solder, if you have a small bit of heatshrink then you could slide that along the earth wire first, do the connection then slide it back over the connection and shrink it...


you will also hear the earthing washers being referred to as "Banjos" and "Frying pan handles" by Electricians...due to their shape


Use an Earth core as a CPC (circuit protective conductor) and also bond/connect the steel armour to earth as well...
 
Guys: This is getting silly, the original post is something like 3 years old & was accidentaly resurrected by trev due to a browser problem.
 
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