Is this conduit suitable

[Glyn1959]

I have two 1.5mm cables and one 2.5mm cable in a surface mounted plastic conduit (the type with the self adhesive tape backing).The external width of the conduit is 25mm. The cables fit in ok and I don't want the conduit any wider than necessary (the white plastic stands out on the bare timber wall of my summerhouse) but is this acceptable or too crowded? I'm thinking of heat generation etc.
Would appreciate your advice.
Thanks

 

[ricicle]

What are the cables feeding and what size/type are the protective devices ?

 

[RF Lighting]

Did you know you can buy wooden and wood effect trunking? It wouldn't stand out so much

 

[Glyn1959]

It's 4mm radial cable (armoured) to outside single socket then inside 2.5 mm to double socket and up to fused spur (5Amp) then 1.5 mm down to switch and the 1.5 mm back up to 2 small LED lights. There is about a metre when all three cable are in the trunking together. I don't know what protection is at the distribution box as I'm getting a sparky to connect so basically whatever is needed.
I didn't know about the wood effect trunking I was thinking about maybe wood moulding on top if I couldn't get used to the white plastic.
Thanks for the replies so far.

 

[ban-all-sheds]

I'm getting a sparky to connect so basically whatever is needed.

How come it's not already connected?

Have you recently installed all of this yourself?

Do you live in England, or Wales?

 

[securespark]

Strictly, it's too crowded.

There is a 45% spacing factor for trunking.

You need MT3, or equivalent.

This may be best:

http://www.tlc-direct.co.uk/Main_In.../Dline_Wood_Index/Dline_50_25_Wood/index.html

 

[Glyn1959]

I am in the process of installing myself (to keep the cost down). My sparky has agreed to check before connecting. Just wanted your opinion on the trunking. Like the look of the wood effect! What is the significance of where I live?

 

[ban-all-sheds]

If you live in England or Wales then you are legally obliged to apply for Building Regulations approval before you start, which will involve showing how you will ensure that the work will comply with Part P, or to use a registered electrician who can self-certify compliance.

//www.diynot.com/wiki/electrics:part-p

There is a big difference between an electrician checking something over before he connects it and him issuing the necessary documentation - it's unlikely he will be prepared to lie and say that he did it.

You should be asking him all the design and installation questions.

I don't know what protection is at the distribution box

Bit tricky then to choose the right cable size, isn't it.

4mm² SWA could mean that the protective device is too high a rating for 2.5mm² - the electrician might refuse to connect it.

• //www.diynot.com/wiki/electrics:mcbtocable
  
  
• http://www.tlc-direct.co.uk/Book/4.3.1.htm
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/cableselection_web.pdf
  
  
• http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
  

 

[Chri5]

It's trunking not conduit.

Your using mt2 which is 16 x 25, mt3 is 16 x 40.

It's only a metre, I'd let it he over crowding split on the thought that grouping for such a small distance and for small load isn't significant to worry about. I take it the summer house isnt mansion house size, and you don't intend to do anything daft like run a lathe, electric heating or high load items in it?

If so then mt3.

You could always paint it afterwards, when you had the work inspected and know you won't be opening it up again.

 

[Glyn1959]

I take you point. The sparky recommended 4mm so I was not restricted to what I could use in the summerhouse (e.g. small electric heater). Having routed the 4mm cable (some 30 metres) I want to run an outside socket and double socket and two LED lights inside. How do I do this when you say that the protective device required may be too high for 2.5 mm cable. Should the 4mm run to the socket and then continue to the fused spur (5Amp) thereby eliminating the need for any 2.5mm cable?

 

[ban-all-sheds]

Do the Building Regulations apply to you?

If so, what are you doing about notification/certification?

It could be that you must not ask anybody except your electrician.

 

[Glyn1959]

Simple advice required, that's all. Isn't that what forums are all about?
Should it be 4mm straight through to the 5A fused spur or not?
Thank you

 

[ban-all-sheds]

The advice was simple, and the question I asked is of huge importance, and until answered then nobody can safely give you any advice.

Do the Building Regulations apply to you?

If so, what are you doing about notification/certification?

It could be that you must not ask anybody except your electrician.

It could be that if you ask people other than your electrician and you then expect him to sign documents to say that he made all of the decisions you will be USCWAP.

 

[Glyn1959]

My sparky has made no reference to building Regs applying.
He was originally doing the whole job (as a favour as he has a lot of committments at the moment). I wnt to do the summerhouse end of the job and then ring him to check, connect, check again and sign off.
At the end of the day if he isn't happy he will say so, change until he is and then connect and sign off.
I'm just looking for other people's opinion that's all!

If it makes you happier your answer regarding the 2.5mm cable could be "theoretical".

 

[ban-all-sheds]

My sparky has made no reference to building Regs applying.

I would have thought this would be easy enough to answer:

Do you live in England, or Wales?

He was originally doing the whole job (as a favour as he has a lot of committments at the moment). I wnt to do the summerhouse end of the job and then ring him to check, connect, check again and sign off.
At the end of the day if he isn't happy he will say so, change until he is and then connect and sign off.

Well - as long as you are happy to take the risk that he won't be prepared to lie for you.

Or, if Building Regulations do apply you're happy to take the risk that he'll break the law and you'll not have the necessary documentation.

I'm just looking for other people's opinion that's all!

In the absence of any other info, keep it 4mm² to the FCU.