DIY Cable from Bungalow to outside garage

[pcprorepairer]

I would like to run a new cable to my outside garage AND THEN get an electrician to connect up and test - so would someone be prepared to give some advice please?

Current set up is the existing cable to the outside garage is on its own circuit, i.e. 1 cable from the consumer unit with a B16 fuse. The cable from the consumer unit fuse is ring main cable approx. 5 meters into the loft to a  junction box. from here it uses what must be 60 years old weird looking cable about the thicknes of coaxial cable, orange pvc outer sheaf, negative and positive wire inside a metal casing, which must be used as the earth wire as it connects to earth in the junction box. This goes across and around the loft space approx.15 meters then out through the soffit board and down the outside wall approx.3 meters before disappearing underground for approx. 15 meters  then surfacing at bottom of garage wall, through the single brick wall and up to a modern metal 2 gang socket with a fused lighting spur inside the garage. This was working until a lightning strike nearby a couple of years ago. I know there is power from the consumer unit to the old cable junction in loft (I replaced the fuse which was blown with the lightning at the time) but nothing in the garage so presumably the old cable is defunct. I have left the fuse switched off at the consumer unit and never bothered as didn't have much use of the garage. Now it's time to get it sorted.

So if you still with me....my thoughts are to dig out and trace the old cable and lay a new one in place with a bit of surplus  either end and then get a pro to connect to the garage and consumer unit. My questions are: what size cable is needed for this: assume it has to be ASW as it goes underground and will be exposed on part of the wall: if so does this ASW need to go right back to the consumer unit or just the junction box; or none of this as it was mentioned I can use 13amp ring main cable all the way enclosed in flexible pipe (the sort used to fish ponds) where it goes underground.

Appreciate any answers or ideas apart from the obvious one to forget any part DIY and get a pro electrician in from the start!

 

[Murdoch]

get a pro electrician in from the start!

You have the best idea!

 

[pcprorepairer]

Thanks for your help...just why I decided to post a question on here

 

[Sharpend]

What are you likely to be using in the garage that requires power? 

 

[ProDave]

I would first be asking someone to test it and find where the fault is. It may well be the buried cable is okay and replacing it is a waste of time.

If you are going to all the trouble of replacing the cable I would put something bigger than the original cable in.

 

[binky]

sounds like you have MICC cable - ruddy good stuff if it is still in servicable condition. My advice would be to get an electrican on board before you start, they can then advise on cable size, which will be dependent on what load you envisage,  and how to run it.

 

[pcprorepairer]

What are you likely to be using in the garage that requires power? 

small power tools, perhaps a freezer and plug in a lawnmower

sounds like you have MICC cable - ruddy good stuff if it is still in servicable condition. My advice would be to get an electrican on board before you start, they can then advise on cable size, which will be dependent on what load you envisage,  and how to run it.

It looks so flimsy though compared to modern day armoured cable. I probably will get electrician just wanted to try and save a bit of money by doing the digging as I'm sure that's not something they would want to do if avoidable

 

[binky]

yep MICC is tiny becuase it is so good! Any damage to the end 'pot' that allows mosture in and it's ruined, worth insulation testing to see if it's any good, as your loadings are low, so 16Ais probably enough.

 

[Evans Electric]

You 'll certainly save a bit by doing the digging .  And if you drop the cable in . 

And I'd say your maximum load would be  no more than10A  .   No heater going in there then ? 

Measure the cable run for us ....  trench say 18 inches deep ..  long enough  to reach board in house ..2 m up the garage wall  and we'll come up with a cable size.  

 

[pcprorepairer]

That's easy as already done measurement:  2m up garage wall 15m underground along a fence line 3m up the house wall into loft then 19 m to board TOTAL = 39m

No heater perhaps a 1kw fan heater if working during cold weather otherwise mostly hand tools electric drill suchlike

 

[Evans Electric]

Lets go with a 16A  design  load then , at  40M  long .  

 

[Murdoch]

So lets get this straight .......... no idea about the earthing? no idea about the suitability of the existing main earth or bonding, or the existing fuseboard.......... buts lets crack on and give dubious advice to Joe Public.......... very odd

Back to the OP ........... no spark ever wants to dig trenches, let alone 40m ones ............... and yes, I have done this with a customer, but the route of the cable, the depth, the back fill, etc etc was agreed before anything started .................. and then the cable was supplied by me, laid in by self and customer ........... customer back fills trench............. then its connected up and tested......... and if its Part P .......... that's done too.

 

[binky]

MiCC is only ever installed by those who know what they are doing, now, might be out of date, but as stated above 'get an electrican involved from day one' . Wind your neck in and try reading the posts @Murdoch

 

[Murdoch]

Wind your neck in and try reading the posts @Murdoch

I did ................... my points are still very valid

 

[Sharpend]

Where about’s are you, bit of luck and you might have our Murdoch come visit for a site reccy!! 

 

[Apache]

@Murdoch do remember that we pride ourselves on being friendly. This is in the DIY section of the forum. Much better someone comes on here than trails a 50m extension lead out of the bedroom window for the next 10 years.

Help, be constructive or stay out of the DIY section. Thanks

 

[OnOff]

@Murdoch's points are pretty valid imo.

 OP hasn't said how the cable in the loft is run, is it buried in insulation? Is the "ring main" cable really 2.5mm2? Earthing system at the cu might dictate whether 2 or 3 core swa be used, whether to put the garage on its own rod etc.

Could just be a loose jb terminal. 

 

[binky]

it's not what you say, it's the way that you say it ! 

 

[Sharpend]

it's not what you say, it's the way that you say it ! 

Or is it the way people receive it? 

Whilst Murdoch may be direct with his approach what he says isn’t actually wrong, so why do people take issue with the direct approach- perhaps it’s the nanny state that we live in where you offend people before you speak these days? 

 

[pcprorepairer]

@Murdoch do remember that we pride ourselves on being friendly. This is in the DIY section of the forum. Much better someone comes on here than trails a 50m extension lead out of the bedroom window for the next 10 years.

Help, be constructive or stay out of the DIY section. Thanks

That maybe has given me the answer I want. Why do some of you so  called tradesmen always want to be elitists? I'm in business myself and deal with customers all the time.I just wanted a bit of advice and constructive ideas....this seemed the ideal place for that as it had a DIY section. OK there were a couple of helpful posts but overall I've been left feeling a complete numpty how dare I even suggest doing anything myself. So Thanks but I'm off...you'll be pleased to hear I've found a helpful local sparky (well qualified) to sort this out.