SWA - earthing the steel wire?

[John R]

Hi

I’m new to the forum & just a DIY’er!

I’m running a 15m length of 2.5mm 3 core (twin & earth) SWA to our decking at the back of the garden for a double socket.

Must the steel wire armour be earthed using the banjo or is the CPC core sufficient?

Thanks in advance!

J

 

[Silly Sausage]

Yes, it must be Earthed.
Make sure you use the correct glands, properly, as well

 

[SJD]

Yes, the steel armour must be earthed. Use the correct gland, rated for the location, and either the banjo or a piranha nut.

So that if someone digs through the cable, the armour cannot become live.

 

[telectrix]

the armour must be earthed at the source end even if you have a separate cpc conductor.

 

[Risteard]

I'd prefer to see it earthed at both ends. Also will reduce the loop impedance.

 

[Midwest]

Alright, that’s four of you that said it must be earthed. Thought someone might have added something else to the discussion.

 

[telectrix]

Alright, that’s four of you that said it must be earthed. Thought someone might have added something else to the discussion.

i can add loads to the discussion.....

1. why do you ask when it's clear in BS7671?
2. is it being installed by a competent sparks?
3. where's my beer? (this Q for missus, as she's only doing washing, ironing, washing up, dusting, cleaning, women say they can multi-task, so why my beer not within reach?

 

[SJD]

Alright, that’s four of you that said it must be earthed. Thought someone might have added something else to the discussion.

What would you have liked adding? The OP didn't ask about anything else, e.g. RCD protection, etc.

 

[Midwest]

What would you have liked adding? The OP didn't ask about anything else, e.g. RCD protection, etc.

Doesn’t normally stop people.

 

[Deleted member 26818]

Nice cut of tea, and perhaps a biscuit.

 

[Taylortwocities]

I’m running a 15m length of 2.5mm 3 core (twin & earth) SWA to our decking at the back of the garden for a double socket.

I'll add a bit more.
SWA cable is not "twin and earth". SWA cable is 2,3,4 core etc. All cores are separately insulated. You may choose to use one of the cores for earth. Or you could use the steel armour (subject to a number of tests, calculations and checks) as the earth.

The flat stuff that is used for fixed wiring inside a house , like this

is twin and earth.

 

[John R]

Thanks for the decent answers. I made it perfectly clear that I am a DIY’er. I realise that there are a BC & wiring regulations but I cannot justify the £££ needed to purchase them.

I also realise that I need RCD protection and that the cable needs to be buried 500mm down with the plastic warning tape less deep.

I know what traditional ‘twin & earth’ is...what is this then?

SWA Single Phase Armoured Cable - https://www.toolstation.com/swa-single-phase-armoured-cable/p57367#full-desc

If everything is clear in the regs then why have a forum for advice?

 

[Pete999]

SWA 3 Core

 

[Spoon]

Welcome to the forum mate.
I presume you know this work is notifiable, under Part P?
I take it that you will be notifying them. I've been told that this will cost a bit.

 

[Pete999]

Thanks for the decent answers. I made it perfectly clear that I am a DIY’er. I realise that there are a BC & wiring regulations but I cannot justify the £££ needed to purchase them.

I also realise that I need RCD protection and that the cable needs to be buried 500mm down with the plastic warning tape less deep.

I know what traditional ‘twin & earth’ is...what is this then?

SWA Single Phase Armoured Cable - https://www.toolstation.com/swa-single-phase-armoured-cable/p57367#full-desc

If everything is clear in the regs then why have a forum for advice?

Because BS7671 "The Regs" are a right PITA for electricians to understand, let alone Joe Public, sometimes the voice of reason is better understood.

 

[Midwest]

Nice cut of tea, and perhaps a biscuit.

You been on the gin again.

 

[Pete999]

You been on the gin again.

Gin is a Girls drink

 

[John R]

My stepson is a sparky & checks all the stuff I do & signs it off. He’s coming over next week to show me how to change the consumer unit!!

 

[John R]

Welcome to the forum mate.
I presume you know this work is notifiable, under Part P?
I take it that you will be notifying them. I've been told that this will cost a bit.

Thanks Spoon - yes, I know.

 

[Midwest]

Gin is a Girls drink

Arh but you see, it early use was for inducing bravery on the battlefield.

Besides which, red wine just makes your teeth red & breath stink.

PS I'm not biased

 

[ipf]

My stepson is a sparky & checks all the stuff I do & signs it off. He’s coming over next week to show me how to change the consumer unit!!

Why not ask him for advice, then?...….with all this regular work that you do.

 

[DefyG]

'd prefer to see it earthed at both ends. Also will reduce the loop impedance.

I agree both ends, but from design perspective either/or should be used in calculations for a cpc not both.

 

[Blaspark]

W

I'd prefer to see it earthed at both ends. Also will reduce the loop impedance.

Do you mean an earth rod?

 

[Taylortwocities]

No he doesnt. He means that if you use the armour + one of the cores for the earth then the resistance of the earth path will be reduced.

 

[Blaspark]

No he doesnt. He means that if you use the armour + one of the cores for the earth then the resistance of the earth path will be reduced.

Ok

 

[dksanders]

My stepson is a sparky & checks all the stuff I do & signs it off. He’s coming over next week to show me how to change the consumer unit!!

For him to be able to legally sign anything off, he has to be there at specific points in the jobs progress, he also has to be registered under a Third Party Certification scheme, is he?

Who'll be doing the required testing before and after the job and who'll be completing the Electrical Installation Certificates and Part P to LABC notifications?

It's worrying when we hear an amateur attempting a job that can potentially cause death or injury, if not now, but in the future; who doesn't know what they're doing. (Your original question proves that).

Professional, legitimate electricians have had to invest £1,000's in training, test gear, scheme memberships and continual updating of their knowledge and resources. We're professionals for a reason, we know what we're doing, amateurs don't, and with electricity that's a dangerous situation.

"any idiot can get a circuit to work, but it takes knowledge to get it to work safely"

 

[Blaspark]

For him to be able to legally sign anything off, he has to be there at specific points in the jobs progress, he also has to be registered under a Third Party Certification scheme, is he?

Who'll be doing the required testing before and after the job and who'll be completing the Electrical Installation Certificates and Part P to LABC notifications?

It's worrying when we hear an amateur attempting a job that can potentially cause death or injury, if not now, but in the future; who doesn't know what they're doing. (Your original question proves that).

Professional, legitimate electricians have had to invest £1,000's in training, test gear, scheme memberships and continual updating of their knowledge and resources. We're professionals for a reason, we know what we're doing, amateurs don't, and with electricity that's a dangerous situation.

"any idiot can get a circuit to work, but it takes knowledge to get it to work safely"

Harsh but fair

 

[jdinduntocher]

The regs are there for a reason mainly to stop people and animals being killed, but why not ignore them and take a chance it's only red tape

 

[Flanders]

You don't need rcd protection for the SWA cable .Have you check with your stepson that you have the correct size of cable for what you are supplying ?

 

[Blaspark]

You don't need rcd protection for the SWA cable .Have you check with your stepson that you have the correct size of cable for what you are supplying ?

The cable is for a socket is it not?

 

[Flanders]

The cable is for a socket is it not?

Then fit an rcd socket , the swa cable does not require rcd protection.

 

[Spoon]

I'm sure the OP's stepson will tell him everything he needs to do.
Not sure why he's here, if his stepson will be signing off everything.
Maybe he's on holiday....

 

[Blaspark]

Then fit an rcd socket , the swa cable does not require rcd protection.

Seems like you're being hard headed, is your football team losing?
Every cable requires protection!
I'd stick the rcd in a dB for many reasons. If you want I could explain them.

 

[Blaspark]

I'm sure the OP's stepson will tell him everything he needs to do.
Not sure why he's here, if his stepson will be signing off everything.
Maybe he's on holiday....

... In a country with no Internet or phones it would seem

 

[Spoon]

Then fit an rcd socket , the swa cable does not require rcd protection.

Seems like you're being hard headed, is your football team losing?
Every cable requires protection!
I'd stick the rcd in a dB for many reasons. If you want I could explain them.

Nothing wrong in @Flanders post. It's to the regs.

 

[Blaspark]

Nothing wrong in @Flanders post. It's to the regs.

Most rcd socket can't be Ir tested. It's suboptimal at best. Outdoor socket no ability to Ir test = trouble brewing.

What I said about every cable requiring protection is true. He said the cable did not require rcd - very misleading

I misread or he edited his comment. I thought it said cable did not require protection. Not rcd protection

 

[Flanders]

The cable is for a socket is it not?

Then fit an rcd socket , the swa cable does not require rcd protection.

Seems like you're being hard headed, is your football team losing?
Every cable requires protection!
I'd stick the rcd in a dB for many reasons. If you want I could explain them.

Yes there are good reasons for both and im not saying you are wrong . Some cases it may be cheaper to fit an rcd socket than fit rcbo , or there no room in the board to fit an rcd , the list go on , or it could be easier and cheaper to fit an rcbo in the board .I was just pointing out that a SWA cable does not require rcd protection , O and I don't follow the football ☺

 

[Blaspark]

Then fit an rcd socket , the swa cable does not require rcd protection.

Yes there are good reasons for both and im not saying you are wrong . Some cases it may be cheaper to fit an rcd socket than fit rcbo , or there no room in the board to fit an rcd , the list go on , or it could be easier and cheaper to fit an rcbo in the board .I was just pointing out that a SWA cable does not require rcd protection , O and I don't follow the football ☺

I've posted why rcd socket is a bad idea. Feel free to disagree.
I apologise for being harsh on you. I'll make an effort to to be nicer

 

[Flanders]

I've posted why rcd socket is a bad idea. Feel free to disagree.
I apologise for being harsh on you. I'll make an effort to to be nicer

That what I'm saying i don't disagree you can put the rcd where you like ☺ Just read my post properly in the future ☺ps i did not edit it .

 

[Spoon]

I'll make an effort to to be nicer

Send me cake..

 

[Blaspark]

That what I'm saying i don't disagree you can put the rcd where you like ☺ Just read my post properly in the future ☺ps i did not edit it .

My post was only a little wrong, in that I misread one word. I said I would be nicer but still going to call a spade a spade. Your advice could have caused an accident your response to my calling it out was seriously suboptimal and not taking into account things a spark should.

Send me cake..

You can guess from the tone of the paragraph above the probability of a cake coming your way.

 

[Deleted member 26818]

Can I have cake to go with my cut of tea?

 

[Blaspark]

"there no room in the board to fit an rcd"

Which manufacturers make mcb's that can't be switched out for rcbo?
This is a question not a jibe

 

[Deleted member 26818]

Wylex 3036and 1361 fuse boards.

 

[ipf]

Your advice could have caused an accident your response to my calling it out was seriously suboptimal and not taking into account things a spark should.

…..and that's just another reason why giving out advice to those of ignorance, on an open forum, can help cause havoc.

 

[Blaspark]

…..and that's just another reason why giving out advice to those of ignorance, on an open forum, can help cause havoc.

This board seems quite quick to do that. I see it from both perspectives... If people want to mess around and burn their house down that's their business, if they are going to burn down a block of flats that's a different matter.

 

[Spoon]

You can guess from the tone of the paragraph above the probability of a cake coming your way.

 

[Taylortwocities]

Never mind the cake, I have a whole bag of popcorn here, and enjoying the show.

 

[Simonslimline]

Thanks for the decent answers. I made it perfectly clear that I am a DIY’er. I realise that there are a BC & wiring regulations but I cannot justify the £££ needed to purchase them.

I also realise that I need RCD protection and that the cable needs to be buried 500mm down with the plastic warning tape less deep.

I know what traditional ‘twin & earth’ is...what is this then?

SWA Single Phase Armoured Cable - https://www.toolstation.com/swa-single-phase-armoured-cable/p57367#full-desc

If everything is clear in the regs then why have a forum for advice?

This is a forum for electricians. Not a place to spoon feed DIY enthusiasts that are too tight to get the job done by somebody competent. How are you going to test the work?

 

[Blaspark]

This is a forum for electricians. Not a place to spoon feed DIY enthusiasts that are too tight to get the job done by somebody competent. How are you going to test the work?

By licking his finger...

And the home page of this forum says "free electrical advice" not "professionals constantly learning"

Personally I think it is very funny