Why is power commonly routed through foundations?

[peroni]

Most people when preparing the foundations for an observatory seem to go for the buried pipe option and route cables for power and/or networking through the pipe up into the obsy from the floor.

Why don't people go in through the walls? Isn't that easier?

In my mind I'm planning an obsy (one of the pulsar domes):

• It seems that putting a pipe in the ground will just fillup with water from the open ends.
• The pipe end in the obsy floor would get in the way. You could plan to get it close to walls but with limited room you'd just end up tripping over it.

Benfits of through the wall are:

• Power on the wall where you need it
• Nothing to trip over
• It's off the floor so if leaks happen then power problems are less likely.

So, what's the generally accepted view. Is drilling holes in a dome obsy a bad idea?

[Tinker1947]

Most of the underfloor routing would be getting to the pier so there's no tripping up, other wiring is or should be routed through the wall voids.......

[red dwalf]

cables that are buried are safe on the outside of the obsy of course but i came up though the floor and tacked the inside cables around the outside walls of the obsy putting power boxes in where i needed them then ran one to the pier under the floorboards for power to the pier and mount.  

[peroni]

Excellent. Thanks chaps. It's all clear now.

I will need both. This build gets more complicated by the minute. :-)

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[laser_jock99]

Cable don't necessarily have to be buried in concrete to reach the pier. If you have a raised wooden floor around the pier like many do - they can just run under the flooring up to the pier. If you have a hollow steel pier they can even run up inside the pier. It is easy to arrange some removable floor boarding so you can access the wiring at any time.

[Ptarmigan]

gets more complicated by the minute.

You are right there !

It is not just the entry to the obsy that is complicated.

There is the (small) matter of how the power gets to the region of your obsy.

It used to be simple, you either buried it or you strung it overhead.

But now, if you permanently install it, you need to get the relevant permissions from your local authority.

If you are a qualified installer then not a problem, else you need one to either approve your work or do the work for you, making sure that there is no water trap and that the power is suitably isolated from other services.

Sorry for the bad news (, which you may already be aware of ? )

[peroni]

But now, if you permanently install it, you need to get the relevant permissions from your local authority.

I had not considered that. More options to decide on. I will have to start writing them down :-)

At one stage I thought about just running an extension cable down to the obsy (only about 15-20m). I guess I need to decide how permanent I want to make the installation.

My thoughts were not to treat this as a remote obsy but instead to sit inside and work/operate from there. So all I'd need is a 240v power feed from the house/garage.

[Ptarmigan]

just running an extension cable

I see you caught the sub-text of my bold bit !

[dmahon]

There should be a better way of powering your laptop from a 12V battery than converting it to AC in an inverter then using an AC/DC converter to get it back to 19/24V. Some kind of step-up transformer.

[MikeP]

I use a PSU that takes 12V as input and outputs 15, 16, 18, 19, 20, 22 or 24V.  I think I bought it from Maplin.

I actually have two - I connect them to both to a 60aH leisure battery and run my laptop and a screen with no problems at all.

Mike

[peroni]

I use a PSU that takes 12V as input and outputs 15, 16, 18, 19, 20, 22 or 24V.  I think I bought it from Maplin.

I actually have two - I connect them to both to a 60aH leisure battery and run my laptop and a screen with no problems at all.

Mike

There should be a better way of powering your laptop from a 12V battery than converting it to AC in an inverter then using an AC/DC converter to get it back to 19/24V. Some kind of step-up transformer.

When I first started out I used a small maplins battery to power my mount but once I'd figured out that my interest lay in astrophotography and locally from my backyard, I invested in a maplins 12v DC supply (from FLO ofc :-) ). 

I had a few occassions when either my mount battery or camera battery would run flat when the skies were clear. Most frustrating!

So the mount is mains powered via 12v DC supply,

my camera is powered via 12v DC and one of those battery thingies that connect to 12v supply,

my laptop just needs a 240v supply to save the battery from running low. I can use the same 240v supply that provides power to the 12v DC transformer.

Basically, I'll run a 240v supply out to the obsy. From either an extension cable that I can detach/roll up each night. Or from a permanent external 240v supply wired up by an electrician (not me).

[Tinker1947]

I run a 240v supply out to my Obby, its connected to  RDC 3 pin plug in  my Workshop then 5 metres of heavy rubber cable to a caravan type 3 pin socket on the outside wall, i not sure if its legal or not but that's how it is and thats how its going to stay, i could disconnect and take it back into the workshop when i not in use, but can't be bothered...

[mhard26339]

I run a 240v supply out to my Obby, its connected to  RDC 3 pin plug in  my Workshop then 5 metres of heavy rubber cable to a caravan type 3 pin socket on the outside wall, i not sure if its legal or not but that's how it is and thats how its going to stay, i could disconnect and take it back into the workshop when i not in use, but can't be bothered...

That is how I am going to do mine Ray. I have an outside powerpoint (certified) close to the hot-tub normally used for the garden lighting, it will either go to a twin socket or one or the other!

[dmahon]

As long as the receptacle receiving power is male, it's safe. If the receptacle giving power is male, someone is potentially going to get killed.

Make sure the inlet is male (an "inlet socket").

[peroni]

A useful picture. Thanks for posting. It helps to get things clearer. I'm a long way from the doing stage but it's nice to get the direction sorted.

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[mhard26339]

Hi, i have just picked up a dome and I intend to get the power in the same was a Tinker 1947, input the same as on a caravan and corresponding lead, female socket, male input completed with RCD at the other end.

Regards

Mike