1.5mm SWA, Acceptable or bad practice ?

[TPES]

I know it depends on its inststallation method but what is the max current carrying capacity of 1.5mm swa 3 core?

If im looking at the correct table 4D4A it says 18a clipped direct.

But then this manufactures spec says 32a. (page 3) http://www.alertelectrical.com/upload/pdf/329armoured.pdf


I want to know if its acceptable to run a radial to 2 x outdoor sockets using 1.5mm SWA on a 16a mcb

 

[Mac]

Radials should be run in 2.5mm and put on a 20A breaker.

 

[sparks1234]

Radials should be run in 2.5mm and put on a 20A breaker.

Why?, nothing to say you cant back a 1-5 cable up with a 16 amp, personally I would install a 2-5 (obviously dependant on length) but cant see why you could condemn the 1-5

 

[TPES]

Radials should be run in 2.5mm and put on a 20A breaker.

Thats a new one, I thought perfectly acceptable on 16a.. this is T&E

SWA has a larger current carrying cappacity thinking a 10m run in 1.5mm SWA would be ok..

According to this its 26A. 1.5mm 3 core Armoured Cable

Either way its well within the 16a MCB it would be on..

Is it bad practice and most of you would not consider this?

 

[Mac]

Why?, nothing to say you cant back a 1-5 cable up with a 16 amp, personally I would install a 2-5 (obviously dependant on length) but cant see why you could condemn the 1-5

Personally you would install a 2.5mm.I would definitely install a 2.5mm and put it on a 20A breaker.I'm not condemning the 1.5.Each to his own and my preference

Thats a new one, I thought perfectly acceptable on 16a.. this is T&E

SWA has a larger current carrying cappacity thinking a 10m run in 1.5mm SWA would be ok..

According to this its 26A. 1.5mm 3 core Armoured Cable

Either way its well within the 16a MCB it would be on..

Is it bad practice and most of you would not consider this?

I would still install 2.5mm.You don't know what they will plug into it at the end of the day.

 

[TPES]

dont dissagree with you, I would also install 2.5mm, its just that the customer has huge amount of 1.5mm and wondered if i could use it.

 

[Mac]

dont dissagree with you, I would also install 2.5mm, its just that the customer has huge amount of 1.5mm and wondered if i could use it.

Just run 2 lengths up then mate

 

[pevvers]

I would still install 2.5mm.You don't know what they will plug into it at the end of the day.

At the end of the day, if the cable is protected then the installation is safe, and a 1.5mm SWA will be okay on a 16A.

Thermosetting single phase SWA comes in at 27A with no corrections, so I'd say you would probably be okay with it even on a 20A, as long as you've done the corrections of course!

If im looking at the correct table 4D4A it says 18a clipped direct.

Are the sockets 3 phase then? As the single phase uncorrected CCC for thermoplastic is 21A in my book...

 

[Mac]

At the end of the day, if the cable is protected then the installation is safe, and a 1.5mm SWA will be okay on a 16A.

Thermosetting single phase SWA comes in at 27A with no corrections, so I'd say you would probably be okay with it even on a 20A, as long as you've done the corrections of course!



Are the sockets 3 phase then? As the single phase uncorrected CCC for thermoplastic is 21A in my book...

So your happy putting sockets on a 1.5mm cable

 

[pevvers]

So your happy putting sockets on a 1.5mm cable

Ummmm, am I protecting the cable from overcurrents?

Yes.

Whether it be lighting, sockets, FCU's, it matters not as long as the cable and all associated equipment is protected from overcurrents, will disconnect in the required time, etc., etc.

Just because it's 1.5 doesn't mean it can only be used for lighting, just like you could put in 16mm radial circuits for sockets if you really liked, although you would have a hell of a time getting them in the terminals!!

As long as the calculations add up then you are complying with BS7671, which is what I adhere to.

 

[scotsparky]

i would put sockets on a 1.5 and have done after i made the micc end off.

 

[andyb]

90 degree, 1.5 armoured clipped direct single phase, 27 amps.
Can anyone tell me why, providing all the other factors allow you would not protect this with a 20
amp mcb.

 

[pevvers]

90 degree, 1.5 armoured clipped direct single phase, 27 amps.
Can anyone tell me why, providing all the other factors allow you would not protect this with a 20
amp mcb.

Exactly. I don't know why people think that if it's a radial to a socket on 16A or 20A it needs to be 2.5 no matter what the cable type is. Someone's already brought up that it's okay for MICC, so why can't they see that it would be okay for SWA? Especially as the CCC of 1.5 MICC that are exposed to touch is less than that of 90 degree armoured!

But hey ho, some people are told that this is the way we do it, and they can't be budged even when common sense and proof from a British Standard document is in the mix.

 

[tigerpaul]

Agree fully with pevvers..

It may be the norm to have sockets on 2.5 and lighting on 1.5 but that isnt the be all and end all. As long as the cable is protected by the overcurrent device then thats it. (Dont forget Rating factors)

How many sockets are you feeding? And how many are likely to be in use at one time. One 13A socket is only going to draw up to 13A, if the cable is rated at 20 odd A and the overcurrent device is 16A, then I cant see a problem.

 

[Spudnik]

Personally i cant see a problem, however, i do see it as good practice to use 2.5 for socket outlets.