Advice on swa as tails

[BES]

Hello people
Got job to replace/move cu going to be using 25mm 3 core swa as tails as ive never used swa as tails before im after a bit of advice. Do i earth armour of cable at supply end using a 16mm fly lead to gland. As im using the 3 core 25mm how do you terminate the earth in the cu earth terminal as all domestic cu ive seen only accept max of 16mm. One more question the customer has asked me to quote to install two showers one in main bathroom one in en-suite i thought two electric showers in one property was not good practice as could lead to over load problems if used at same time, with going down the route of installing equipment to allow only one to run at a time, time just wondered what others opinion on this was. Dont want to lose work, as i know some will fit without a care , advice please.
Ta
neil

 

[dnk1983]

you can get pin crimps for the 25mm that would allow you to install the cable to the earth bar. i would definitely earth the armour too but you shouldnt need to go as big as 16mm. 10 or 6mm should be fine. the only thing i would check for with regards to the showers is to try and calculate the maximum demand currently in the property and then add both showers to see if the main fuse can handle the load.

 

[BES]

Thanks dnk forgot about those pin crimps. Even 2 8.5kw showers are approx 70a dont think it will be a problem at present time as only two people in house but if two adult and three kids moved in.

 

[telectrix]

to get round the 25mm earth, use a MET external to the CU, then from MET to CU in 16mm. as dnk says, 10mm fly lead to armour is adequate. what earthing system is it?

 

[BES]

cheers tel
Yeh thought about using henly block as met and as you said 16 from there to cu. Its TNCS. Ta

 

[telectrix]

and i wouldn't worry about the showers. many houses have 2 installed. just limit the kW to 8.5kWeach.

 

[BES]

cheers tel yeh thats what i thought ta

 

[cobrauk]

Just in case you are not aware that if you are installing the SWA over a long distance from the meter you will have to add a isolator

 

[GLENNSPARK]

give up guys....an old BS951 that you find lyin around will suffice...:cowboy::joker:

 

[Amp David]

Trim a few strands off that beastly 25mm then it'll fit nicely into that earth bar:cowboy:

 

[jumpin jax]

Just in case you are not aware that if you are installing the SWA over a long distance from the meter you will have to add a isolator

It would require a switch fuse instead of an isolator to protect the swa

 

[james29022004]

you could always use a 2 core armour in 25mm then run a seperate 16mm earth depends on length/route of cable run.I would use 100a switchfuse next to cutout to connect tails to swa(you could use 80a to provide discrimination but i was told by helpline not to worry as their fuse protected their tails then to design circuit to protect my installation)

 

[BES]

Thanks for replysl
Its only a run of approx 2.5m from cut out so no need for switchfuse. Swa cleated to external wall into garage to new cu.

 

[nickblake]

what i do is a Galve adaptable box with a bush going into the CDU , bring the earth out of it via a stuffing gland then terminate that into a henly block and distribute the earths from there , take the other tails into the board or if you CDU can take a 25mm the the same but strip off the armour and gland it into the box and take the 3 cores and the inner insulation the one the armour covers straight into the board

 

[BES]

Thanks nick good ideas
Only problem that concerns me is as swa is run external from meter cabinet best way to get cable into cabinet its flush mounted with only a small lip to cut into.