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?