50mm uPVC duct to a Pier?

[Alan White]

So as this has been missed from question on my other thread.

So here is my question.

Started the Pier and cupboard project with available materials during lock down;
keeps me sane, keeps me active and exercises body and mind.

So anyway, a 1m duct for 12v etc to a future Pier for visual use, but may become more in years to come.
I have a length of 50mm or 2" in old money uPVC drain or a 110mm or 4" drain pipe.
What's the wisest choice to cut under the existing concrete slab from cupboard to pier location?

Your thoughts much appreciated, thank you 😀

Edited April 13, 2020 by Alan White

[Gina]

I have 2" pipework for my cables which is adequate but bigger is probably better.  Don't forget to run at least one draw string through the duct to allow for adding more cables - you will certainly need to, whatever you may think now!  If you add bends make them wide radius and not a sharp elbow.

[Alan White]

Having talked this through with a number of members of CPAC and others too,
I will run with the one 50mm Waste Pipe, with 1 x 135 degree bends each end forming a slow bend upwards.
At present this will be empty, but going forward probably only have 2x 12v supplies and perhaps a cable to the mount for EQMOD.
Clearly it will all change as time goes on.
 

[Gina]

Put a draw string through before assembling the bands to the straight part.  You'll find it difficult or impossible to push cables through.

[Alan White]

5 hours ago, Gina said:

Put a draw string through before assembling the bands to the straight part.  You'll find it difficult or impossible to push cables through.

Will do Gina, thanks for that.
Saves later hand wringing.

[Carbon Brush]

Excellent advice from Gina.

If running a single 12V cable I  would recommend using at least 2.5mm sq cross section.
Copper-wise this is the size of domestic ring main. But use flexible cable. 50/0.25 stranded equipment wire, or something similar. Twin and earth is definitely not flexible.
Alternatively run multiple 1mm sq cables, keeping mount and dew heaters separated.

Plan for the future. When I built my observatory in 2007 scopes had much less associated electronics than they do today.
USB or wired network to a mount was almost unheard of.
A few spare cables in your duct cost very little and it is easier to thread them through now, rather than later.

I fully agree with 50mm pipework. I fitted 40mm waste pipe and it is looking busy now.
If you are having to buy fittings, etc, why not just buy a length of 50mm smooth bore flexible conduit?
This avoids the lips associated with joints, making it easier to pull cables through, and avoids risk of joint leakage.

HTH, David.
 

[bottletopburly]

Tbh i would use bigger pipe at least 3"  i used 30mm for only a short distance  and that's too small  and was a pain lesson learnt ,found the easiest way to run cable was to suck fine cord using Henry hoover ,have you got far to run 

[Alan White]

50mm is in and concreted in, see my Observing Area thread.

The duct is 1.5m long from pier location (yet to be built) and cupboard for power, eyepieces, laptop, tea mug etc.
 

Edited April 20, 2020 by Alan White