Trunking cable capacity

[Ducksy]

Hey folks, im wiring in a shower circuit, i've decided on singles in PVC trunking (10mm line/neutral) (4mm CPC) I've worked out my cable factor in trunking as 87.2...................Problem is OSG shows smallest size trunking as 50mm X 38mm Thats way to big!!!!

Can anyone point me in the right direction for the trunking factors for smaller pvc trunking......?

Sorry if it sounds a dumb question but i normally use twin and earth clipped direct......sod fitting that in trunking.

Thanks.

 

[MDJ]

(10mm line/neutral) (4mm CPC) .

Can I ask why a 4mm2 CPC?

 

[pennywise]

You can quite happily fit 10mm T+E in MT4 trunking

 

[Ducksy]

Can I ask why a 4mm2 CPC?

I couldn't be bothered to work out the adiabatic (probably be 2.5mm cpc) runs only 10 meters and i have some 4mm lying around.

You can quite happily fit 10mm T+E in MT4 trunking

Thanks mate i never use trunking normally ref method C

 

[MDJ]

If it was singles I would run a 6mm2 haha, I would like to run a 10mm2, but it would be a complete nightmare to connect into the pull cord switch, so 6mm2 would just have to do, but everyone to their own, in a T&E I am aware it is only 4mm2, another silly decision by the cable manufacturers.

 

[Ducksy]

If it was singles I would run a 6mm2 haha, I would like to run a 10mm2, but it would be a complete nightmare to connect into the pull cord switch, so 6mm2 would just have to do, but everyone to their own, in a T&E I am aware it is only 4mm2, another silly decision by the cable manufacturers.

I would love to use 6mm but the shower is a 10.5kw....in trunking 6mm CCC is only 38a far below the 44a needed

 

[jaydee81]

think he means using 6mm cpc

 

[Ducksy]

think he means using 6mm cpc

I think your right lol

Ok out of bordom im going to work out min CPC............PFC =1.4kA using a 45A BS60898

i get a min CPC size of 3.8mm

 

[D Skelton]

I think you're working it out wrong, you might even find 1mm could be sufficient.

 

[Ducksy]

I think you're working it out wrong, you might even find 1mm could be sufficient.

I probably am lol.......pob....I showed my girlfriend a video of pob washing he's pants on YouTube....the **** we used to watch....she had no idea who he was....I felt old lol

 

[Englishman]

You can quite happily fit 10mm T+E in MT4 trunking

You can fit it in mt2 as well!

 

[Ducksy]

You can fit it in mt2 as well!

but what about bends ECT hate trying to crush it in.

 

[pennywise]

You can fit it in mt2 as well!

without any hint of a bend yes

 

[Essexboy7]

In over 25 years in the game i have seen numerous bits of trunking either plastic or metal absolutely rammed solid with cables.Plenty of times i have seen whole bottles of fairy liquid and planks of wood and hammers used to crush even more in,and bits of lid tied on with tie wraps because the buckles wont turn.And that is on new build prestige jobs not just lash ups.What is in the OSG quite often bears no resemblance to what happens on site

 

[Engineer54]

In over 25 years in the game i have seen numerous bits of trunking either plastic or metal absolutely rammed solid with cables.Plenty of times i have seen whole bottles of fairy liquid and planks of wood and hammers used to crush even more in,and bits of lid tied on with tie wraps because the buckles wont turn.And that is on new build prestige jobs not just lash ups.What is in the OSG quite often bears no resemblance to what happens on site

I don't think that could be called a ''Prestige Job'', if that's what's being allowed to happen!!

 

[happyhippy68]

For prestige read lowest possible tender price to the contractor and maximum profit to the developer. I agree with Essexboy7, it happens all the time. I spent a week last month, in an International Banks flagship office sorting out some prestige work that looked just like that!

 

[Essexboy7]

Jubilee line extension
kings cross Eurostar
westfield shopping centre white city
The shard
The Gherkin


To name but a few.And you dont get more prestige then those jobs


Its all down to greed and poor design.At the first sign of trouble the easiest thing to do is admit the containment is too small and rip it out and put bigger stuff in,but that means either the designer admitting they got it wrong or the subby swallowing the cost of labour to rip it out and replace it and neither of hose 2 things are ever going to happen

I suppose you dont have to worry about a fire as theres no room for any oxygen in there!!!!!!!

 

[DNS1]

I think you're working it out wrong, you might even find 1mm could be sufficient.

Agreed mate, I'm totally bewildered by this thread! How long is the bloody run to need a 4mm CPC?!

How does running in conduit change CPC size anyway?

 

[Engineer54]

Jubilee line extension
kings cross Eurostar
westfield shopping centre white city
The shard
The Gherkin


To name but a few.And you dont get more prestige then those jobs


Its all down to greed and poor design.At the first sign of trouble the easiest thing to do is admit the containment is too small and rip it out and put bigger stuff in,but that means either the designer admitting they got it wrong or the subby swallowing the cost of labour to rip it out and replace it and neither of hose 2 things are ever going to happen

I suppose you dont have to worry about a fire as theres no room for any oxygen in there!!!!!!!

No bloody supervision on site more like, and an electrical contractor that isn't worth a ----!! Never been on a project yet, where it's not part of the electrical contactors responsibility to conform to the standards the specification is based on!! If the stipulated sizes of trunking or any other containment system is not adequate for the job, then it is down to the contractor to raise the issue!! A contractor working on these types of projects will, without doubt have a Quantity Surveyor as part of the team, who would be looking for just this sort of thing, to make ''Extras'' on, for both materials and man-hours!! It's where contractors can make serious money, and why the QS are worth their weight in gold on big projects!! So your explanation makes no sense at all contractually!!

 

[Ducksy]

without any hint of a bend yes

MT4 it is then