Ok to run swa in pipes above ground through the garden?

[bpowell555]

You've had a month to learn about cable capacities and voltage drop - why haven't you used it?

Watcha misery guts - ru my dad?

edit: ok ban-all-badgers I'm going to edit my reply slightly as you are "the don" of sheds... I use this site sometimes as a reference not always for projects being done at the time, so I can look back to see where I got to on a project. I don't always have the time to follow stuff through. Hence why a gap of a month or two crops up, could be a year, doesn't matter when its all down here in 1s and 0s - hope that makes sense

 

[bpowell555]

Hi quick question as I start to buy materials for this one... is 2.5mm ok? What if I run a 2000W circular saw plus a couple other bits?

Cheers!

Here is a rough guide that should help you make a more informed decision:

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

If you need to get a spark to test and inspect, or 'tie up' your new installation anyway ( as stated in your OP ) then it is probably better to get your quotes in and ask the sparky what cable he wants you to use. Your chose sparky maight have something suitable in the back of the van.

It will depend on the spark whether he decides to certify your work, if i was signing off I'd rather have the householder dig any trenches

i often have to sign for other peoples work as a supervisor/inspector in my own job- whether i sign depends on what the work is, how it was done and who did it.....

Thanks thats a useful link - I was looking to use them for the bits - and some good advice I figure the cable length is not more than 15m so 2.5mm should be fine ... although maybe I'll run 4

 

[bpowell555]

edit, is there an up2date version of this with the pictures working?
//www.diynot.com/forums/viewtopic.php?p=219838#219838[/QUOTE]

Hows this?

//www.diynot.com/wiki/electrics:swa-gland[/QUOTE]

That is nothing less than DIY Pr0n

 

[bpowell555]

You dont want conduit!

You want duct...

http://www.drainageonline.co.uk/products.php?category_id=18[/QUOTE]

The duct in this link does look really good but I only need 15 metres, and the linked duct is expensive for a minimum of 50m.

Is there no way to make a waterproof join in something like this?
http://www.tlc-direct.co.uk/Products/MT20HGB.html

Cheers!

 

[securespark]

How're you going to get SWA down conduit??

 

[regsmyth]

[quote="RF Lighting";p="901797

Hows this?

//www.diynot.com/wiki/electrics:swa-gland[/quote]

Just curious - did you sleeve the live and neutral or is that a trick of the eye?

 

[Click-Sure]

Sleeving is available in a number of colours, not just green and yellow!

 

[333rocky333]

Looks to me like 3 core red yellow blue
Red sleeved brown
yellow sleeved gr/yellow

 

[dullSpark]

Do they do it in a nice pink?

 

[Click-Sure]

Oooh, it would be so nice, we could leave it as some kind of trade mark, not used as sleeving, but a little coil of it nesting in the corner of all boxes we visit

 

[bpowell555]

Ok cheers all. Since I'm not digging in most of it - just a short length under a path that I'll mark appropriately - figure I don't need to future proof with large cable. Also the case since I won't run it back to the CU just an FCU, so capped to 13amps in any event. Although, for voltage drop should I be measuring from the CU or from the FCU? I measured the voltage at the socket I would spur off and its 240.

Was thinking this for the FCU:
http://www.screwfix.com/prods/14770...3A-RCD-FCU;jsessionid=RPRGVP4F3WCVECSTHZOSFFY

outside to:
http://www.screwfix.com/prods/20485...t;jsessionid=RPRGVP4F3WCVECSTHZOSFFY?ts=09648

T&e to the back then 2.5mm swa down to the shed. I estimate the total cable run is 18m, about 2.5m underground. All cable would be in duct, the above ground part against a batten fixed to fence post.

Once in the shed I'd terminate the swa in a 4 way weatherproof box:
http://www.screwfix.com/prods/59385...x;jsessionid=RPRGVP4F3WCVECSTHZOSFFY?ts=10432

Then onto 3 sockets and a light switch. Alreet?

 

[ban-all-sheds]

edit: ok ban-all-badgers I'm going to edit my reply slightly as you are "the don" of sheds... I use this site sometimes as a reference not always for projects being done at the time, so I can look back to see where I got to on a project. I don't always have the time to follow stuff through. Hence why a gap of a month or two crops up, could be a year, doesn't matter when its all down here in 1s and 0s - hope that makes sense

None of that alters the fact that a month ago you knew you needed to find out about voltage drop etc, and you've not done so.

 

[bpowell555]

edit: ok ban-all-badgers I'm going to edit my reply slightly as you are "the don" of sheds... I use this site sometimes as a reference not always for projects being done at the time, so I can look back to see where I got to on a project. I don't always have the time to follow stuff through. Hence why a gap of a month or two crops up, could be a year, doesn't matter when its all down here in 1s and 0s - hope that makes sense

None of that alters the fact that a month ago you knew you needed to find out about voltage drop etc, and you've not done so.

Well I have now - even got the multimeter out - friends?

 

[dullSpark]

You do realise that voltage drop only occurs when there is load on the conductor, infact modern multimeters have a practically infinite resistance.

You could attach wet string to a multimeter at one end and 230v at the other and it would show 230v (probably and this is not recommended), the problem comes when you apply a load to the wet string; then the impedance of the string will gang up with the impedance of the cable you have connected it to, the load, the transformer and the generator; and of course very little current will flow. Your faithful multimeter will then show the voltage across the string falling like a stone.

Fortunately, rather than guessing a cable size, installing it and then applying load and measuring the voltage drop; we can use tables to work the voltage drop. Resistance and thus impedance doubles every time we double the length, so a 1meter long cable will have twice the impedance of a 2meter long cable. Normally of course this isn't a problem, but over long runs it can be. Fortunately impedance is also proportional to conductor area, well roughly anyway (skin effect can occur in large round cables), so by choosing a larger cable we can reduce voltage drop.

Of course the load is just as important as the length of cable, a 1amp load on a 2 meter long cable will show the same amount of voltage drop as a 2amp load on a 1meter long cable.

Pardon the rant, but this isn't the whole story, but I thought it might make you think about what exactly you need to do.

 

[ban-all-sheds]

skin effect can occur in large round cables.

They'd have to be bl***y large to have a radius greater than the skin depth at 50Hz....