Gina's Observatory - The Build

[RogerTheDodger]

Amazon are sneaky like that, you are tracked with your browser cookies - if you spend a lot with them, then some prices are higher. I see it as £13.75 as I don't use them much.

[michael8554]

On my account it says £18.75 too

But just under the price it says

"5 new and used from £13.75"

Click on that and you're offered a choice from £13.75 up

[Gina]

£13.75 plus £5.61 shipping!

[Gina]

Today's Progress.

Yes, actually done something to my build today Preparing for it's eventual permanent power supply. Been removing concrete blocks and trench digging. That's my exercise for today!

The weather started off frosty and almost cloudless and turned into a nice sunny day with the temperature rising from around freezing at dawn to 5C this afternoon. Having spent the morning making the big shed goat proof, I made use of the afternoon for a bit of "ME" time

In detail :-

1. Unscrewed part of wall panel and pulled it out a bit to get to bottom of framework.

2. Drilled hole through framework to take armoured cable.

3. Fed armoured cable up through hole into wall cavity.

4. Removed concrete blocks along path by side of house to provide part of the trench for the cable.

5. Started digging trench from warm room end towards house.

Here are a couple of photos of the work done.

[Freff]

I thought you'd finished with the spade Gina.

[Gina]

I thought you'd finished with the spade Gina.

Maybe I have - I've been using a grub-axe alias Mattock today

[Gina]

Today's Progress.

After a cloudy start, today turned out to be a nice sunny day again and warmed up in the sunshine, reaching 8C this afternoon. So made use of the good conditions to continue "planting" my mains supply cable, across the lawn.

Used a spade today to cut through the turf and make a slit to drop/push the cable into. It's now well below ground level as far as the back porch, which is where I intend to take it indoors (up through the floorboards). I also drilled a hole through the wall panel in the warm room to take it into the RCD/CB box. It's in there now ready to be connected up just before I do the house end. Meanwhile, the RCD (and hence all the obsy mains electrics) is still connected to cable and 13A plug and plugged into an extension cable from the house.

Here are some photos. The first shows the armoured cable coming up through the hole in the framework of the west wall of the warm room, from where it goes on up and out through a hole in the panel to the RCD/CB unit. The others show the trench and part of the slit for the cable to be buried under the ground.

[Gina]

A bit of progress today.

Miserable drizzle day most of the time but I did manage to get the final ceiling panel measured up, cut to size and screwed up to the roof framework.

[dark knight]

Gina it would be a good idea to place bricks on edge over the armoured cable and then the turf/soil back. This will provide additional protection to the cable and stop someone sticking a spade through it in the future. It's all too easy to forget the route of the cable after awhile and this could save someone's life from a nasty surprise.

[Gina]

Gina it would be a good idea to place bricks on edge over the armoured cable and then the turf/soil back. This will provide additional protection to the cable and stop someone sticking a spade through it in the future. It's all too easy to forget the route of the cable after awhile and this could save someone's life from a nasty surprise.

Yes, I did think of something like that but thought they might rub on the cable and eventually wear into it. Something a bit softer in between is a thought, but not wood as it rots.

[MikeWilson]

Can you put the cable in some uPVC pipe? That's how the power cabling to our shed is protected.

[Gina]

Yes, I could do that.

[Aoraki]

If it's SWA cable, I don't really see the need for further protection if it's buried deep enough.

[Gina]

If it's SWA cable, I don't really see the need for further protection if it's buried deep enough.

It is, and that was what I thought.

[dark knight]

Fair enough if it's SWA.

[dark knight]

Gina, just for info on burying cables,

also it would appear that wiring up the obsy is governed by Building Regulations Part P as notifiable works. Srry just the ex Building Regs Inspector in me coming out.

http://www.pistonheads.com/gassing/topic.asp?t=1009136

[GJBC]

yep had to follow those regs on the obs at Cardiff went down 600mm and used the tape on top of fine gravel surrounding the cable before covering with back fill. we had the mains cable connected both ends by a qualified electrician as that was the only way they would certify its correct installation we also had the cable run approved by an electrician before we could cover it in. we also had to have the observatory mains and lighting installation certified as all as it was a permanent connection to the mains.

the one thing we had to follow the full procedure as we had to get full planning permissions as it was near a listed building and used by the public. building regs only were concerned with the electricity due to nature of the building. the grounds owner stipulated we had to have it certified as it is on council grounds. the electrical fitter was Part P qualified and he brought in an outside contractor to certify his work. i am sure that any new extension to the household mains will need certification. worth checking out..

if it was mains connection by extension cable that was classed as temporary and a different level of certification was needed. at a lesser level. crazy i know but we always knew we would have to do it so it never came as a supprise.

Like Gina the electrical run was the last thing to go in but it was supposed to be there by time our base went in. so our base had a waste pipes burred to allow for later running of the armored cable.

we also had to have the correct size armored cable installed at the insistence of the electricians and building regs due to the length of the run and voltage drop over that length so it never got overheated.

we done the internal fitting out ourselves but we had been given clear instruction by our electrician on what we needed to do to meet certification Ian has an electrical qualification himself but the person we were working for (I.E. our electrician) would be putting his name against the installation so he had to have it correct. as it was we had to alter one cable run as the sleeve on the cable never quite made it into the plug box took two mins to sort out and he was happy. the pier had to be earthed as well as the mains circuit board to ground outside the obs.

sorry bit of a ramble as things came into my head

[dark knight]

Safety should always come first, ya don't get many second chances when it comes to electricity. Just want you to be safe Gina, I have seen the resulting burns from mains electrocution and he was lucky, he only got burnt.

[Gina]

I totally agree with great care being required for mains wiring and I have had a fair amount of experience - I even did it as part of my job some years ago. And to a higher standard than domestic supplies. As for household electrics, when I bought a pre-war bungalow many years ago and needed a mortgage I was told a complete rewire was required as the wiring was the original 1938 vintage rubber covered cable. I completely rewired the premises including consumer unit ready for connection by the electricity company. The installation was checked by both the building society approved electrician and council (I think) plus the electricity company who reconnected the supply. I was actually praised on a good job I have also done other domestic wiring.

[Gina]

As for the connection at the house end, I have been thinking a lot about how to connect it to the household supply. Although permanently wiring into an unused fuse in the fusebox directly would probably be the ideal arrangement, it would require a lot of work to run the armoured cable to the fusebox. I'm now thinking of using an RCD unit connected to the household supply by a 13A plug, probably connected by standard power cable to the spare fuse (currently a 15A one). It's much easier running ordinary twin & E cable than the thick, stiff and heavy armoured cable.

Having an RCD unit indoors would provide protection from any possible problem with the feed to the obsy. I still think an RCD consumer unit in the obsy is worthwhile as it provides independent switching and overload protection to the power and lighting circuits in addition to earth leakage detection.

[JamesF]

I wouldn't take the armoured cable any further than the wall, Gina. Internally I'd have standard twin+earth of an appropriate size back to the consumer unit (or into an RCD that is cabled up to the spare fuseway in the CU), then join both cables in an appropriate junction box.

(FWIW, you *may* be able to get an RCD that fits into your CU even if it's only designed to take fuses. The sparkies who did the work for our solar panels told me that we should be able to get them for our CU which is designed for cartridge style fuses.)

Given the choice I'd not go anywhere near the CU in the house and just take another feed off the meter tails into a combined cut-off switch and then out to the obsy, but putting the junction in the meter tails is certainly not a game I'd want to play myself.

James

[Gina]

I wouldn't take the armoured cable any further than the wall, Gina. Internally I'd have standard twin+earth of an appropriate size back to the consumer unit (or into an RCD that is cabled up to the spare fuseway in the CU), then join both cables in an appropriate junction box.

I've be looking through my stuff and found an RCD junction box with 13A fuse. I could connect the armoured cable into that and run T&E from there to the spare fuseway.

(FWIW, you *may* be able to get an RCD that fits into your CU even if it's only designed to take fuses. The sparkies who did the work for our solar panels told me that we should be able to get them for our CU which is designed for cartridge style fuses.)

There's very little room around the fuse bank and main switch so that wouldn't be on.

Given the choice I'd not go anywhere near the CU in the house and just take another feed off the meter tails into a combined cut-off switch and then out to the obsy, but putting the junction in the meter tails is certainly not a game I'd want to play myself.

James

I'm not going anywhere near the meter tails without having the incoming main fuse out and that needs to be done by the electricity supplier which would involve cost and inconvenience. I don't work on live circuits if I can possibly avoid it.

[JamesF]

I've be looking through my stuff and found an RCD junction box with 13A fuse. I could connect the armoured cable into that and run T&E from there to the spare fuseway.

That seems like the most sensible approach then.

I'm not going anywhere near the meter tails without having the incoming main fuse out and that needs to be done by the electricity supplier which would involve cost and inconvenience. I don't work on live circuits if I can possibly avoid it.

I know a few people who think it only needs to be done by someone with a supply of the tamper-evident seals for the fuse cover However, I agree with you completely. (Again, when we had the sparkies in for the solar panels) we had a kill switch for the entire house installed immediately after the meter so fortunately we won't need to deal with the supplier when we have other circuits added in the future.

James

[Gina]

With inclement weather lately, I'm concentrating on getting all the kit working. Currently trying to sort out computers to go in the warm room. The netbook is rather small and poor spec for what I'm proposing to do so I'm sorting out a couple of towers. Yes, a couple because they're old machines running Pentium 4 HTs at around 2-3GHz with 2GB of RAM. Plenty of HD space available though. Running the DSLR (1100D) in RAW will produce vast amounts of data.

I'm already running the netbook with a 17" monitor (bought 2 from Morgan for about 70 quid the pair). I have in mind running the mount control (and guiding later) on one machine and image capture on the other. I will be having 2 USB2 cables from warm room to mount to keep control separate from data.

I have yet to work out how everything fits together software-wise. I don't know if DSLR control wants to be on the same machine as the data recording - I imagine it does as there's only one USB lead to the camera.

The machine I'm working on ATM has built-in wireless LAN so I'll probably use that for imaging with thoughts of transferring image files to my main dual core machine indoors, for processing. I rather think a P4 HT would be rather underpowered for image processing.

[pritc]

I have yet to work out how everything fits together software-wise. I don't know if DSLR control wants to be on the same machine as the data recording - I imagine it does as there's only one USB lead to the camera.

Gina,

For complete Canon DSLR control/capture of lights/bias/darks,APT is the way to go.

For the price,it is fantastic program.

Ivo the developer is always improving the software,with regular update releases.

www.astroplace.net - APT - Introduction

Wayne