Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 48 replies
  • Subscribers 32 subscribers
  • Views 4444 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

DIY domestic wiring to outbuildings

Former Community Member
Former Community Member
Hello, I am new to the forums and would like to introduce myself. In the past I have undertaken a lot of domestic wiring as a DIYer. Most of this predated the Part P requirements. However, in 2013 I undertook a fairly major wiring project at my home that included two new consumer units and half a dozen or so circuits. I did this under building control and they arranged inspection and testing. I secured a full set of certificates to underpin my work. I am about to go through the same process to add in two outbuildings to my set up. I have submitted a building notice and am awaiting to hear from Building Control re appointment of a firm to undertake inspection and testing.

Whilst I gather most DIY work scares many of you you, worth pointing out that whilst I am not any form of electrical Engineer, I do have (from many years ago) a HND in Mechanical and Production Engineering and a B Eng (Hons) in Engineering Technology. Both of these included a significant element of electrical technology and electronics. I have also worked in engineering (aerospace) for much of of my early career and still work in a STEM environment. Further,  intend to do a short course on the latest regulations and may also undertake a C&G course on testing and inspection to possibly get to a point where I can register with one of the governing bodies.

I have come to this forum as I am designing my changes and preparing for the first fix. i have been seeking guidance on the internet and from the regulations themselves. I find the regulations open to many interpretations and the advice on many forums to be wildly different. I really want to get this installation right and will have many questions, most requiring practical experience that I simply do not have. I believe this forum will be able to guide me in the right direction when I need it.


My first question relates to burial of SWA. I had a digger in last week to put in a series of trenches for cables. I intend to do all of the external wiring in SWA and in an ideal world would have buried it at 600mm. However, I have places in the garden where it is not possible to get that deep. For an example, under one lawn I have an underground structure that limits the trench depth to 300mm. What would be a appropriate method for installing SWA at this depth? Do I need to add something to prevent a spade/fork penetrating the cable, if so, what would you recommend? I also need to watch my budget here so looking for cost effective views if possible.


There will be further questions. Thank you.


regards

Parents
  • 0
    Strictly speaking that is the armour Chris, not the sheath (which is plastic). The yellow warning tape is a good idea, and the depth beneeth the lawn at 300 mm and the tape at say 100mm should warn anyone digging adequately. It is quite difficult to cut SWA with a spade, and if you do you will certainly trip the CPD (circuit protective device) or an RCD if used. You don't say if this is a distribution circuit (to a remote consumer unit) or a final circuit, but if the latter you should protect the whole lot with an RCD. There will now be discussion about the earthing method and PME from some people, please ask for further advice although you will need to provide details, and use information. Any joints or ends to this cable will need special glands, which clamp the armour, and have specific sizes for various sizes of cable. Waterproof types are available where you need to prevent water ingress to the cable itself. The armour may be used as the earthing conductor, although many people like to use 3 core cable, with one core for earth, but the armour must be earthed anyway in case of spade attack etc. It is not a lot more expensive than 2 core, or sometimes even cheaper so shop around. 3 core cable has brown, black and grey cores for 3 phase use, but you can relabel as you wish, although it is probably best to use the brown core for live, and many like the grey for neutral with a blue identification added. The black core should be labelled with green and yellow as normal for earth. Fitting the glands (particularly CW waterproof ones) needs some practice but you should see instructions on youtube. Come back for more information as required.
Reply
  • 0
    Strictly speaking that is the armour Chris, not the sheath (which is plastic). The yellow warning tape is a good idea, and the depth beneeth the lawn at 300 mm and the tape at say 100mm should warn anyone digging adequately. It is quite difficult to cut SWA with a spade, and if you do you will certainly trip the CPD (circuit protective device) or an RCD if used. You don't say if this is a distribution circuit (to a remote consumer unit) or a final circuit, but if the latter you should protect the whole lot with an RCD. There will now be discussion about the earthing method and PME from some people, please ask for further advice although you will need to provide details, and use information. Any joints or ends to this cable will need special glands, which clamp the armour, and have specific sizes for various sizes of cable. Waterproof types are available where you need to prevent water ingress to the cable itself. The armour may be used as the earthing conductor, although many people like to use 3 core cable, with one core for earth, but the armour must be earthed anyway in case of spade attack etc. It is not a lot more expensive than 2 core, or sometimes even cheaper so shop around. 3 core cable has brown, black and grey cores for 3 phase use, but you can relabel as you wish, although it is probably best to use the brown core for live, and many like the grey for neutral with a blue identification added. The black core should be labelled with green and yellow as normal for earth. Fitting the glands (particularly CW waterproof ones) needs some practice but you should see instructions on youtube. Come back for more information as required.
Children
No Data

Community Rules & Guidelines