Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_celestial_motion.thumb.jpg.a9e9349c45f96ed7928eb32f1baf76ed.jpg

Uranium235

Electrical safety & operating temp

Recommended Posts

Hiya,

I will be getting my first scope and mount tomorrow (150p + CG5 GT)... Yay!! I will probably spend the daylight hours checking collimation and aligning things up.

And in preparation, Ive made space in the shed for a chair and a table for the laptop - I need to be in the shed to avoid the attentions of the neighbours PIR security light sensor :) (Ive had so many shots ruined by that damn thing!).

The plan is to run a mains extention into the shed from a powerbreaker socket in the kitchen. Im just a little concerned with the amount of snow on the ground and the kind of temperatures I will be working in if i decide to have a go this weekend (probably -10).

Would it be a good idea to get a plastic box (with lid) that i can dump all of the electrical connections in (eg: adapters, 4 gang socket) to protect them from any possible contact with snow, water or dew?

Also there are the safe operating temperatures of the equipment. My cameras (D60) minumum operating temp is 0 - so how would it cope with -10? (then there is the laptop too) If theres any chance that that damage could result, then it might be better to wait til its warmed up a bit.

Is there a temperature that would be considered "too cold" for safe/useful operation?

Many thanks in advance :)

Share this post


Link to post
Share on other sites

If there is any likelihood of water getting into contact with something electrical - protect it. You don't need to worry about cabling across the ground, but if you have a plug/socket half way across the snow, you should insulate it from the snow...

Share this post


Link to post
Share on other sites

Remember to press the test button on the Breaker to make sure its working properly... and then reste it for use...

As Arad said keep the mains stuff other than the cable off the ground and as dry as possible...

Share this post


Link to post
Share on other sites

Okey doke :) will check the test switch and keep it to just the main cable on the floor, its a 10 metre extention so most electrical connections will be inside the shed, Though im not sure how long the CG5 power cable is yet.

I need it to be at least 3 metres becuase the Maplins cigarette lighter mains adapter I have doesnt give much in the way of cable length (about 0.5 metres). The adapter has massive warnings on that it shouldnt be used outdoors, so its something ive got to keep super dry.

If the CG5 cable isnt long enough then its going to be another trip to maplins @ merry hell (groan) :)

Thanks for the assist guys :mad:

M42..... Im on your case!! (assuming its clear skies!) :mad:

Share this post


Link to post
Share on other sites

I think the bottom line here is the old adage "electricity and water don't mix"

Professional electricians refer to a book called the 'On site guide'

IEE On-site Guide; BS 7671 : 2008 IEE Wiring Regulations 17th Edition

IEE On-site Guide; BS 7671 : 2008 IEE Wiring Regulations 17th Edition: Amazon.co.uk: The Institution of Engineering and Techn: Books

Anything outside must have proper RCD protection, if your house has bee wired to Part 16 or above you will have RCD protection on all ground floor sockets anyway - at least you should have !!! (Kitchen sockets should definately have RCD protection - think it's a legal requirement now-a-days check your distribution box)

Don't have a plug and socket half way, daisy chaining extensions is not 'good practice' (although we've all done it. How long is the cable run? too long a run makes your RCD in-effective!

Best bet is buy yourself a roll of blue Arctic cable and make your own extension to length.

Very best bet is have a look through the On-site Guide and dig yourself a trench (1/2 a meter if memory serves me) and bury some 2.5mm three core SWA terminating in an IP56 socket in the shed (don't forget to drill the 3mm hole for condensation). It'll be handy for the lawnmower too!

I know it costs more but an electric shock is a c##p way to learn about electricity.

I think one of the biggest issues with electronics and temperature is the build up of condensation inside, sorry to be the bearer of bad news, but if it says don't use below zero and you use it, who do you blame, as a habitual chancer myself ... I've been through similar angst after it all went horribly wrong!

Personally, I'd turn the laptop on inside, (they generate so much heat that I reckon they're probably self defrosting) then once warmed up carry it out and plug it back in - I haven't done this so again up to you mate.

Share this post


Link to post
Share on other sites

Sound advice there, thanks! :)

Ive already checked the distribuiton box and it seems ok, if anything gets tripped its just going to be the one switch. Its about 8 metres to the shed so I dont think distance will be a problem.

If ever in doubt, before poking anything electrical... keep one hand in your pocket (it will save your life). That message was constantly hammered home while doing my 224.

Lol... wish i had the option to dig a trench but the ground is more than a little solid (and buried) at the moment! The garden also faces due north - which is handy for polar alignment as ive always got a good view of Polaris, but not so great as it means the snow will take quite a while to shift (and theres more on the way).

Hmmm, I do know one way i can warm the lappy up.... just play Fallout 3 or Modern Warfare 2 in windowed mode while imaging... the gfx card (HD4530) kicks out so much heat it will probably keep the shed warm by itself :)

Its just a case of whether the DSLR can take it (is the CCD affected by cold?), I know the temp will slay the battery quite quickly so id better buy a spare i can leave on charge.

Thanks again for the advice!

Share this post


Link to post
Share on other sites

Right... off to fetch it all now.

7am on icy rural roads...... yikes. Better take some carpet and a shovel! Oh, and a flask of coffee :)

Share this post


Link to post
Share on other sites

Ahhh, so I have at least some headroom - I doubt it will reach -15 here. If im having mains power in the shed I could use the little fan heater to raise the ambient temp inside. Theres not much insulation, but it should be warm enough.

Im just setting the mount up now.... god.. Ive soon discovered that the CG5 isnt exactly portable, it weighs a damn ton!!! Reassuring though this is, its not going to qualify as a "grab n go" setup :) the power cable seems nice n' long too, just what I needed!

Next up is to check the collimation of the tube, hopefully it will be good to go out of the box.

If the weather eases off a bit I could go for first light tonight, but its pretty windy @ the mo and there has been more snow this morn....hmphh typical of this to happen!

Might be (or should i say will be!) back with more questions if I get stumped!!

Share this post


Link to post
Share on other sites

The lower them temp the better for the CCD but as you said its a battery killer which Is why i run the cameras from a PSU taht I knocked up using Dummy nbatteries to make the connection... the cameras are complaining about low battery with it in the cold weather where as at more normal temps its set for Half battery level...I could tweak it up a bit i suppose but no probs int he last week...

I have a dimplex 500W "frost" heater in the obs and so far only have the walls and flat roof insulated not the dome itself it keeps it about 4-5C above the outside temp.

Dimplex MPH Range Fan Heaters - More Info. JC Electrics Online Electrical Wholesaler

Have Fun :)

Billy...

Peter...

Share this post


Link to post
Share on other sites

Ive run into my first technical hitch :)

The balance is fine, the secondary mirror had to be adjusted a little (collimation is soooo easy) and ive tested the D60 to see if i can achieve focus ok - which i can :)

But.... with the T-Ring in place and mounted on the scope the camera is reporting "No lens attached".... is there a way to fool the D60 into not doing this?

Thanks in advance for the assist!

Share this post


Link to post
Share on other sites

If you intend to bury the cable when the ground becomes diggable again then get ready for it and run the cable through a suitable length of hosepipe. Very difficult to damage the cable and no probs when burying it. I ran a power cable (25A) from the board to my workshop, a distance of 134 ft and never had a problem. However when I have finished my obsy I shall be running a new cable from my power supply at 12v DC 30A (360 watts). the power unit is in my study. I'll put details up on my website as I get to each stage.

Share this post


Link to post
Share on other sites

I like the idea of using hosepipe as a conduit, thanks for that :)

Its unlikely I will be digging anything yet because Im expecting to move in about 2 or 3 months. Luckily the location will be semi-rural (Worcestershire) so a dark sky site should never be too far away :) Once im settled I will make the installation a more permanent affair.

Bahhh... the clouds have rolled in for the night, looks like first light will have to wait a little longer.

Share this post


Link to post
Share on other sites
However when I have finished my obsy I shall be running a new cable from my power supply at 12v DC 30A (360 watts). the power unit is in my study. I'll put details up on my website as I get to each stage.

How long is this 12V supply cable going to be? You won't need much resistance in the wire at 30A to lose a few Volts. Or does your PSU have sense inputs?

Share this post


Link to post
Share on other sites

The power supply was actually built for ham use. It has soft start and remote at point of use voltage sensing. 12v at the sharp end often means 15/16v at source. The power supply wieghs about 60 lbs!. All I had to do was get a new xformer made.

The cable will be about 50ft long and I will be using 4mm cable. I have the unit open at the mo so I'll take a pic and put it up later.

ray

Share this post


Link to post
Share on other sites

I've used my DSLR (Canon 20Da) in -21C conditions and it continued to work fine - although having to take my gloves off to change settings and batteries wasn't fun. Just be careful with the transition from cold to warm which can cause moisture build up inside.

Share this post


Link to post
Share on other sites
The power supply was actually built for ham use. It has soft start and remote at point of use voltage sensing. 12v at the sharp end often means 15/16v at source. The power supply wieghs about 60 lbs!. All I had to do was get a new xformer made.

The cable will be about 50ft long and I will be using 4mm cable. I have the unit open at the mo so I'll take a pic and put it up later.

ray

You obviously know your stuff :)! You'd be amazed at how many blank looks I get in my job when I ask "does the psu have sense inputs?"

Share this post


Link to post
Share on other sites
I've used my DSLR (Canon 20Da) in -21C conditions and it continued to work fine - although having to take my gloves off to change settings and batteries wasn't fun. Just be careful with the transition from cold to warm which can cause moisture build up inside.

Sorry but:

IF ANYONE CAN................PETE CAN.

That should be the new Canon slogan.

Edited by LukeSkywatcher

Share this post


Link to post
Share on other sites
I think the bottom line here is the old adage "electricity and water don't mix"

Professional electricians refer to a book called the 'On site guide'

IEE On-site Guide; BS 7671 : 2008 IEE Wiring Regulations 17th Edition

IEE On-site Guide; BS 7671 : 2008 IEE Wiring Regulations 17th Edition: Amazon.co.uk: The Institution of Engineering and Techn: Books

Anything outside must have proper RCD protection, if your house has bee wired to Part 16 or above you will have RCD protection on all ground floor sockets anyway - at least you should have !!! (Kitchen sockets should definately have RCD protection - think it's a legal requirement now-a-days check your distribution box)

Don't have a plug and socket half way, daisy chaining extensions is not 'good practice' (although we've all done it. How long is the cable run? too long a run makes your RCD in-effective!

Best bet is buy yourself a roll of blue Arctic cable and make your own extension to length.

Very best bet is have a look through the On-site Guide and dig yourself a trench (1/2 a meter if memory serves me) and bury some 2.5mm three core SWA terminating in an IP56 socket in the shed (don't forget to drill the 3mm hole for condensation). It'll be handy for the lawnmower too!

I know it costs more but an electric shock is a c##p way to learn about electricity.

I think one of the biggest issues with electronics and temperature is the build up of condensation inside, sorry to be the bearer of bad news, but if it says don't use below zero and you use it, who do you blame, as a habitual chancer myself ... I've been through similar angst after it all went horribly wrong!

Personally, I'd turn the laptop on inside, (they generate so much heat that I reckon they're probably self defrosting) then once warmed up carry it out and plug it back in - I haven't done this so again up to you mate.

Excellent Advice

Being a Sparky i was just about to give some Advice but the 17th will cover zone 1-3 wiring wet rooms etc;

I will add that you can buy ready made IP rated leads & sockets for exterior use and should be the only wiring used outside the home with the exception of 110v & transformers, The IP Rating refers to the conditions & and duration of exposure the higher the Ip rating the better protection, from light moisture to fully submerged.

Either pre made leads and sockets, Or an Ip rated enclosure at Ip/65 should do the job for all but the most extreme outside conditions including snow.

And remember to check the insulation of the cables even the lightest of damage can cause injury in these conditions, electricity does not offer a warning or second chance.

If this is going to be your regular spot of use why not have an armored cable with an Ip rated disboard & outlets installed in your shed it will reduce the chance of something going wrong ten fold + insulate your shed with 25mm kingspan too keep the cold and frost at bay, both can be done very cheap.

Share this post


Link to post
Share on other sites
I've used my DSLR (Canon 20Da) in -21C conditions and it continued to work fine - although having to take my gloves off to change settings and batteries wasn't fun. Just be careful with the transition from cold to warm which can cause moisture build up inside.

Ahhh good, then the cam has got more stamina than I have then...lol.. id give up at -15! :)

Also thanks for the info in regard to the cable I should use, though I cant imagine the higher IP rated stuff being cheap. I shouldnt need much though... about 12 meters to be sure (better too much than too little!).

The sky has been a bit grey the past few days (and for the next week probably) so im still waiting for first light. In the meantime I passed some time by making a handy dewshield from laminate flooring underlay and a few staples... cheap & cheerful :)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.