New House Build

[JP19678]

Hey there!

Just joined these forums, hoping to get some valid information on a house build I'm currently in the process of doing. I'm doing as much as I can myself but hiring a sparky for the more technical, electrical sides of things. As I'm trying to save as much as possible, I'm buying the products he needs myself.
Any way, onto the question, just wondering whether I'm going to require a seperate earth cable when using 2 core SWA cable? For reference, I'm going to be powering 3 x outdoor lights in the garden, a pump for a water feature and a small hot tub. I've been informed that you can use the steel wire as an earth but I've read that it is not recommended and could make the surrounding area live if a malfunction occurs. Any information would be much appreciated as I'd rather avoid this for obvious reasons!

 

[TheHandyAndy]

You'll probably find that an electrician can get hold of cable and fittings etc... far cheaper than you can. Why not let him quote to supply as well? As far as what you say about the SWA, I'd say, and bear in mind I'm not an electrician, that it's definetly not recommended that you use the armour as the CPC, although the armour does also have to be earthed.

Andy.

 

[JP19678]

You'll probably find that an electrician can get hold of cable and fittings etc... far cheaper than you can. Why not let him quote to supply as well? As far as what you say about the SWA, I'd say, and bear in mind I'm not an electrician, that it's definetly not recommended that you use the armour as the CPC, although the armour does also have to be earthed.

Andy.

Well the electrician I'm using must be charging commission for buying the cable because I've found a online retailer called Quickbit who are providing me with better prices than he is offering me. For example, http://quickbit.co.uk/swa-cable-2-core < this is the cheapest I've seen it and I can get it cut to the length I require.
And thank you for the advice, this website stocks Earth Cable too so I'll probably just get some of that too. Way too many people (Electricians and DIY-ers alike) telling me I shouldn't use the steel armour as an earth.[/url]

 

[JohnW2]

As far as what you say about the SWA, I'd say, and bear in mind I'm not an electrician, that it's definetly not recommended that you use the armour as the CPC, although the armour does also have to be earthed.

I think you'll find that many electricians would disagree with that, and would happily use the armour as the only CPC. Personally, I'm more comfortable to have one of the cores (as well as armour) as CPC - but that's just me, and some (perhaps many) would say that I'm silly!

Kind Regards, John

 

[JP19678]

As far as what you say about the SWA, I'd say, and bear in mind I'm not an electrician, that it's definetly not recommended that you use the armour as the CPC, although the armour does also have to be earthed.

I think you'll find that many electricians would disagree with that, and would happily use the armour as the only CPC. Personally, I'm more comfortable to have one of the cores (as well as armour) as CPC - but that's just me, and some (perhaps many) would say that I'm silly!

Kind Regards, John

Would you say that it is worth including the earth cable just as an extra precautionary measure? I mean, ok, it may be completely fine to use the steel armour as a CPC but I'd rather not take the risk and just get a length of earth cable too, just to be safe.

 

[JohnW2]

Would you say that it is worth including the earth cable just as an extra precautionary measure? I mean, ok, it may be completely fine to use the steel armour as a CPC but I'd rather not take the risk and just get a length of earth cable too, just to be safe.

As I said, FWIW, I personally am more comfortable to take that very approach. It certainly does no harm, beyond requiring slightly more expensive cable. However, as I said, I think you'll find that many, maybe most, electricians are happy to use only the armour (provided that it is adequate for the circuit).

Kind Regards, John

 

[JP19678]

Would you say that it is worth including the earth cable just as an extra precautionary measure? I mean, ok, it may be completely fine to use the steel armour as a CPC but I'd rather not take the risk and just get a length of earth cable too, just to be safe.

As I said, FWIW, I personally am more comfortable to take that very approach. It certainly does no harm, beyond requiring slightly more expensive cable. However, as I said, I think you'll find that many, maybe most, electricians are happy to use only the armour (provided that it is adequate for the circuit).

Kind Regards, John

Ah, fair enough then. Yeah, I'm going to get the separate earth too. Do not want to be electrocuting any one through trying to save money..

 

[Aragorn84]

Would you say that it is worth including the earth cable just as an extra precautionary measure? I mean, ok, it may be completely fine to use the steel armour as a CPC but I'd rather not take the risk and just get a length of earth cable too, just to be safe.

As I said, FWIW, I personally am more comfortable to take that very approach. It certainly does no harm, beyond requiring slightly more expensive cable. However, as I said, I think you'll find that many, maybe most, electricians are happy to use only the armour (provided that it is adequate for the circuit).

Kind Regards, John

Ah, fair enough then. Yeah, I'm going to get the separate earth too. Do not want to be electrocuting any one through trying to save money..

Not a seperate earth, Use 3 core SWA.

 

[JP19678]

Would you say that it is worth including the earth cable just as an extra precautionary measure? I mean, ok, it may be completely fine to use the steel armour as a CPC but I'd rather not take the risk and just get a length of earth cable too, just to be safe.

As I said, FWIW, I personally am more comfortable to take that very approach. It certainly does no harm, beyond requiring slightly more expensive cable. However, as I said, I think you'll find that many, maybe most, electricians are happy to use only the armour (provided that it is adequate for the circuit).

Kind Regards, John

Ah, fair enough then. Yeah, I'm going to get the separate earth too. Do not want to be electrocuting any one through trying to save money..

Not a seperate earth, Use 3 core SWA.

Ah right, ok then. While we're on the topic, what size would I be looking at to power the aforementioned devices do you think?

 

[bernardgreen]

Use a third core for the CPC as that is protected by insulation from damp.

Using the steel wire armour has the risk of damage to the outer sheath allowing water to reach the armouring and corrosion of the steel will then occur leading eventually to the loss of the CPC continuity.

 

[JP19678]

Use a third core for the CPC as that is protected by insulation from damp.

Using the steel wire armour has the risk of damage to the outer sheath allowing water to reach the armouring and corrosion of the steel will then occur leading eventually to the loss of the CPC continuity.

Ah right, thank you for the information.

 

[JohnW2]

While we're on the topic, what size would I be looking at to power the aforementioned devices do you think?

I suggest you should discuss that with your electrician (who will also have a vie on whether you should use 2-core or 3-core SWA), since it depends upon a number of factors (distances etc.). I would also suggest that you consider installing SWA which is appreciably larger than you currently need - you don't want to be digging it all up again as soon as you decide that you need more power for something in the future! The marginally higher initial cost can be worthwhile in order to avoid additional cost and hassle in the future!

Kind Regards, John

 

[JP19678]

While we're on the topic, what size would I be looking at to power the aforementioned devices do you think?

I suggest you should discuss that with your electrician (who will also have a vie on whether you should use 2-core or 3-core SWA), since it depends upon a number of factors (distances etc.). I would also suggest that you consider installing SWA which is appreciably larger than you currently need - you don't want to be digging it all up again as soon as you decide that you need more power for something in the future! The marginally higher initial cost can be worthwhile in order to avoid additional cost and hassle in the future!

Kind Regards, John

Riight, ok then. Well I'll give him a call and see what he recommends. Again, thanks for the info

 

[JohnW2]

Riight, ok then. Well I'll give him a call and see what he recommends. Again, thanks for the info

Fair enough, and you're welcome. Don't forget that you need to be prepared for him having a different view about the 2-core/3-core issue as compared with the feelings of Bernard and myself!

Kind Regards, John

 

[JP19678]

Riight, ok then. Well I'll give him a call and see what he recommends. Again, thanks for the info

Fair enough, and you're welcome. Don't forget that you need to be prepared for him having a different view about the 2-core/3-core issue as compared with the feelings of Bernard and myself!

Kind Regards, John

Yeah, that's fair enough. I'll mention it to him and see what he says. I've got a feeling he's going to suggest using the armour as the CPC to be honest with you.