T & E in conduit calculation help please

[MikeWindsor]

Hi Guys, I apologise in advance as I have done this a**se about face, I have just finished putting power to my shed ( I am currently training to become a sparks got my 17th edition at pass in Watford shortly) and hoping to use my shed as my part p inspection as hoping to join ELECSA. Anyhow I have run 6mm T and E in 20mm plastic conduit, the run is about 10metres long and it had to go up and around a gate on its path to the shed (its all solid driveway so couldn't bury anything) so there are 7 x 90 degree elbows (never again !) and I want to make sure I have the correct rating but not sure how to work it out ? The OSG page 135 gives me a Cable factor of 58 then on page 136 is a multitude of figures for Conduit Factors but I cant seem to find a formula ?
Much obliged for any enlightenment ! Many thanks Mike

PS Next time I shall learn to terminate SWA instead !

 

[Guest77]

Welcome to the site Mike, I hope you have a sence of humour.

 

[dazza1981]

Seven elbows on route to you shed ? Did you go around every plant pot with a elbow lol

 

[Andy78]

Where to start ? Well first of all you deserve a medal, for geting a 6mm T+E through a 20mm conduit and round 7 elbows. Then you deserve it taking off you straight away for choosing such a silly wiring method.

For cable calculations, everything you need to know reference wise is in appx 4 of the regs. Follow the calculations like you have been shown in your training and you won't go far wrong. Easy eh ?

 

[Guest77]

Hi Guys, I apologise in advance as I have done this a**se about face, I have just finished putting power to my shed ( I am currently training to become a sparks got my 17th edition at pass in Watford shortly) and hoping to use my shed as my part p inspection as hoping to join ELECSA. Anyhow I have run 6mm T and E in 20mm plastic conduit, the run is about 10metres long and it had to go up and around a gate on its path to the shed (its all solid driveway so couldn't bury anything) so there are 7 x 90 degree elbows (never again !) and I want to make sure I have the correct rating but not sure how to work it out ? The OSG page 135 gives me a Cable factor of 58 then on page 136 is a multitude of figures for Conduit Factors but I cant seem to find a formula ?
Much obliged for any enlightenment ! Many thanks Mike

PS Next time I shall learn to terminate SWA instead !

:smilielol5: who says the trade is losing quality standards?

 

[Octopus]

I wouldn't be trying that installation method on a customer site! How long did it take you?

 

[7029 dave]

10 meter run, 7 90's , you must of set round every plant pot. lol

 

[richy3333]

Where's Eng54?

 

[Richard Burns]

I would point out that the conduit factors in the OSG are for single core cables, because you do not run T&E in conduit (normally).
If you were trying to calculate for 6 / 6 / 2.5 you would use 58+58+30 = 146 then turn to the next table look at a ten meter run and then find that it does not cover more than two bends for a 10m run. This would probably be because, since the conduit has to be constructed fully before pulling in, you would never get the cable down there.

 

[Guest77]

Where's Eng54?

Probably sat with his head in his hands weeping lol

 

[Octopus]

Correct formula would be to use 3C SWA - it would be a dam sight quicker to install too!

 

[MikeWindsor]

Ha ha thanks guys for the abuse ! (I do have a sense of humour, you have to when you are 44 married with two young kids and starting a new career ! That you have no clue about) I did wonder what I was doing when I was trying to thread the elbows, although I did find a technique that made it easier towards the end, I am worried about all the black scraping on the PVC though. I was advised to use conduit by a retired electrician, he showed me his garden which he has used conduit to run lighting etc he swears by it ! However when I told him I had used 6mm cable he laughed and said " are you wiring in a kiln so your wife can take up pottery ! " 1st elbow out the house, 2nd elbow up the gate post, 3rd elbow across the top of the gate opening on batton, 4th elbow down the gate post, 5th elbow along the gravel board of a fence 6th elbow through the gravel board straight run to shed, 7th elbow into shed ! Luckily it is my house and not a customers, I not let loose on those yet ! know I have a long way to go and only just started in this industry but I am keen to learn from you experts ! I know I should have used SWA so may be I should use something else when I do eventually try and join a scheme !

 

[MikeWindsor]

I would point out that the conduit factors in the OSG are for single core cables, because you do not run T&E in conduit (normally).
If you were trying to calculate for 6 / 6 / 2.5 you would use 58+58+30 = 146 then turn to the next table look at a ten meter run and then find that it does not cover more than two bends for a 10m run. This would probably be because, since the conduit has to be constructed fully before pulling in, you would never get the cable down there.

Thanks Richard for explaining, do you think I could split the run down from 10 metres into smaller lengths with the bends then total them up to get the conduit factor ?

 

[MikeWindsor]

I would point out that the conduit factors in the OSG are for single core cables, because you do not run T&E in conduit (normally).
If you were trying to calculate for 6 / 6 / 2.5 you would use 58+58+30 = 146 then turn to the next table look at a ten meter run and then find that it does not cover more than two bends for a 10m run. This would probably be because, since the conduit has to be constructed fully before pulling in, you would never get the cable down there.

Sorry another question why does the conduit have to be fully constructed first ? I pulled each piece as I added it ?

 

[Richard Burns]

Thanks Richard for explaining, do you think I could split the run down from 10 metres into smaller lengths with the bends then total them up to get the conduit factor ?

Could do but your results would be odd as you could use smaller conduit for each section compared to the whole run.
e.g using 147 2m and 2 bends = 16mm conduit, 4m and 2 bends = 20mm conduit!

Sorry another question why does the conduit have to be fully constructed first ? I pulled each piece as I added it ?

To ensure that you can pull cables again at a later date if changes need to be made (and if buried in structure 522.8.2 applies) but may be a bit OTT if it is easy to disassemble.

 

[MikeWindsor]

Thanks Richard that all makes sense now, I think I am going to rip out the conduit and install swa I dont want the inspector to think I am a muppet ! Really want to do this right and be a professional ! I will just have to put it down to experience :6:

 

[Engineer54]

It's by far the ideal route, and you need to be under no illusion that there will huge gaps in your experience and knowledge after you have been relieved of your money,

Andy, I'm sure you meant to say ''It's by far ''NOT'' the ideal route''

 

[Diddy]

When you call the scam provider I just tend to ask for Alex.....He like a good drink and is open for a dropsy of say £200 ish.....there ya go jobs a good un and your good to go. Remember though as far as I know only Alex is amiable like this.:stooge_curly:

 

[Andy78]

It's by far the ideal route, and you need to be under no illusion that there will huge gaps in your experience and knowledge after you have been relieved of your money,

Andy, I'm sure you meant to say ''It's by far ''NOT'' the ideal route''

Well spotted, oops. Now edited.

 

[Marvo]

There's already several existing threads about industry deskilling please rather use those to discuss the merits of limited scope quals and suitability for scheme registration.