# Forum Home Renovation Lighting  Power and lighting wiring for home studio

## madmuso

Hey guys, 
I am located in Melbourne.
I am currently in the process of converting my garage into a small music production/ rehearsal space.
Its a long single car garage, I will be turning it into two rooms by building 2 rooms within the garage dwelling. 
I have been reading up on wiring but I am getting confused due to differing suggestions and also due to the fact that some of the info is based in US. 
I only want to do the roughing in of most of the electrical and then get a licensed sparky to fit off everything. 
I have already run a 4mm tps cable from my house meter to the new sub board location in the garage. It was a 25 meter run. Im not sure at this stage how to rough in the cables for power points and lighting. I want to make sure that I dont get any ground loop/hum issues with my audio equipment so here are a few questions. 
1) Does the new sub board need to have its own ground stake? Is it legal to do so? Will it make a difference? I have read about star earthing which requires each power point to have its own ground rod, im pretty sure this is based on US reg's but thought id mention it in case we have a sort of equivalent here in Aus. 
2) I have been told that the power point cable should come from its own separate line/circuit from the sub board and the lighting cable should come off another line/circuit. Is this right? 
3) Does each power point simply get "daisey chained" to the next? Or should each power point location have its own cable running back to the sub board? 
4) Due to voltage spikes and dips in mains supplies, I have been recommended a power conditioner which will maintain a constant 240V and this should be fitted at the sub board which supplies the "conditioned power" to the two rooms. Is this a must? Are these units crap? Does our power really vary in voltage a fair bit? 
5) This is a question regarding roughing in the lighting cable. 
Both rooms will have a single light and light switch, but I also want to be able to control "room B" light from "Room A". Im not sure how to rough this in. This way I dont actualy have to go into the other room to turn the light on or off. 
I hope I have provided enough info, as I mentioned already, my main concern is making sure I dont have any hum, noise or interference in the audio system. 
Any advice at all is greatly appreciated,  
thanks,

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## chalkyt

Oooh! This is potentially another of those "call the electrician" posts. You will find that trying to "rough in" yourself without the electrician's supervision/O.K. is likely to create more problems than it is worth. I would be wary of completing a job like this and issuing a Certificate of Compliance, especially if I couldn't see how the 4mm cable was run, how deep, etc, etc. 
Having said that, it sounds as though you need a bit of information so that you can talk some sense to the electrician. This doesn't answer all of your questions but should point you in the right direction. Firstly, don't expect the electrician to be an expert in avoiding earth loop interference with your audio gear. Seek some knowledgeable audio advice on this (you might even get some from the forum). 
Ideally have separate lighting and power circuits. Power circuits driving amplifiers etc are more likely to be overloaded etc than lighting circuits, so if this happens and the power fails, you don't want to be stumbling around in the dark as well. 
Daisy chaining the power outlets is the normal arrangement. Re the "power conditioner", this is a case of "suck it and see". It shouldn't be a big issue to retrofit something like this if you find you need it. Once again advice from an audio source is the go. Generally the power supply in our major cities is pretty good. 
For the light switching, you need what is called "two way switching". The electrician will know what this is and wire it correctly. 
Overall, know what you want and get the electrician to do it. You really won't save much (if anything) on a relatively small job like this since the electrician will spend as much time checking out what you have done as they would doing it themselves (at least I would, even if I was prepared to sign off on someone else's work).

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## Uncle Bob

One of the band members a sparkie? Or a friend? As, like mentioned above, it might be difficult to find a sparky to sign off on this. 
As for the ground loop hums, these have nothing to do with the MEN (Mupliple-Earth-Neutral) grounding, but all to do with audio signal returns. Best practise is to use only one signal return earth path between components. Even better is to use Balanced audio signals. See here and the links on that page for a great over view Perreaux High End Audio Blog: Balanced vs. Unbalanced Audio 
Cheers Bob

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## Random Username

See the link in my sig for more information on the correct way to do it.   
It's the DIY documentation from the electrical regulator in NZ, where the standards (AS/NZS3000) for electrical wiring happen to be exactly the same (bar a few assumptions about ambient temperature) as Australia.  Unlike Australia, in NZ you've been able to do your own wiring for, oh, something like the last 20 years. 
I understand that the vast majority of electrical providers here prefer/insist that the earth for a sub-main be run back to the main earth. 
Other than that, good luck on finding a sparky to sign off on what you've already done! 
(for more information, you can also use your favourite torrent site for the "aus electrical and telecommunication rules" torrent.)

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## madmuso

thanks for the help guys, I have a family friend who is a qualified sparky who will be fitting everything off, I will get him over to inspect what I have done, anything that needs changing I will do.  
I did some more hunting around on the net and found a really good site and page. After reading it im not so sure that daisey chaining the powerpoints is a good idea. Check out 6.4. and 6.6. on the link below, the whole thing is a good read though!  Wiring a Studio: THE GROUND RULES - 6. Laying Down The Ground Rules 
thanks guys,

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## koshari

so i see you chose 4mm^2 cable for your run,  
just interested in your voltage drop calculation and how you came to choose 4mm?

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## madmuso

> See the link in my sig for more information on the correct way to do it.   
> It's the DIY documentation from the electrical regulator in NZ, where the standards (AS/NZS3000) for electrical wiring happen to be exactly the same (bar a few assumptions about ambient temperature) as Australia.  Unlike Australia, in NZ you've been able to do your own wiring for, oh, something like the last 20 years. 
> I understand that the vast majority of electrical providers here prefer/insist that the earth for a sub-main be run back to the main earth. 
> Other than that, good luck on finding a sparky to sign off on what you've already done! 
> (for more information, you can also use your favourite torrent site for the "aus electrical and telecommunication rules" torrent.)

  I didnt realise that electricity providers prefer you to run an earth from the sub board back to the properties main earth. Does this mean you would need to run the tps cable from the sub board to the main meter box as well as a stand alone "ground" cable from the sub board to main meter box? 
thanks,

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## Uncle Bob

> Wiring a Studio: THE GROUND RULES - 6. Laying Down The Ground Rules

  Hmm, interesting.
I wonder what they do in a commercial studio? Maybe all components are run via isolating transformers.

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## madmuso

> so i see you chose 4mm^2 cable for your run,  
> just interested in your voltage drop calculation and how you came to choose 4mm?

  It was recommended to me by an electrician who said it would be enough for what I will be running, which is basically a computer, single guitar amp, and microphone preamp (these wont be running all at the same time though).

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## oldtrack123

> thanks for the help guys, 
> [1] I have a family friend who is a qualified sparky who will be fitting everything off, I will get him over to inspect what I have done, anything that needs changing I will do.  
> [2]I did some more hunting around on the net and found a really good site and page. After reading it im not so sure that daisey chaining the powerpoints is a good idea. Check out 6.4. and 6.6. on the link below, the whole thing is a good read though!  Wiring a Studio: THE GROUND RULES - 6. Laying Down The Ground Rules 
> thanks guys,

  Hi 
[
1]In that case ASK HIM how HE wants it done 
He can /or should be able to go through the whole lot & tell you EXACTLY what you can do!!  
He is the one who puts his neck in the noose if it is not done correctly 
[2]using the net as a source can be a trap,as the Australian Standards overide any other suggestions 
Earthing of ALL equipment SHALL be in accordance with AUS STANDARDS 
Be wary of using NZ threads, again they do not give the full details of what is required in AUS 
PeterQ

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## Random Username

> Earthing of ALL equipment SHALL be in accordance with AUS STANDARDS 
> Be wary of using NZ threads, again they do not give the full details of what is required in AUS 
> PeterQ

  
I will agree that it's quite hard to understand which rules in AS/NZS3000 apply to Australia (only) and which to New Zealand (only), and I figure that grappling with this complex issue is one of the main reasons you shouldn't undertake DIY electrical work without four years of training.    _If only,_ I mean,_ if only_ there was some sort of key in the Standard as to how to solve this difficult and vexing question...maybe with something like the note shown below, which could be, you know, say, just f'instance, located on page 19 of the Foreword...

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## oldtrack123

> I will agree that it's quite hard to understand which rules in AS/NZS3000 apply to Australia (only) and which to New Zealand (only), and I figure that grappling with this complex issue is one of the main reasons you shouldn't undertake DIY electrical work without four years of training.   _If only,_ I mean,_ if only_ there was some sort of key in the Standard as to how to solve this difficult and vexing question...maybe with something like the note shown below, which could be, you know, say, just f'instance, located on page 19 of the Foreword...

   
Hi 
Oooh yes, you are so correct :Roll Eyes (Sarcastic): 
That is in the foreword to THE Standards 
But no such advise/info is given in YOUR NZ download link
Which are simply part extracts , reworded to be RELEVANT TO  NEW ZEALAND
THAT Is my point!!! :Wink 1:   
PeterQ

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## Random Username

> THAT Is my point!!!  
> PeterQ

  Ohhhhh - you mean these points of difference... (From AS/NZS3000, 2007 edition)
Pg 19 - the Foreward 
Pg 50 - electrical supply tolerances (+10% to -6% for Aust, +-6% for NZ)
Pg 97 - type of RCD (NZ ones should trip on pulsing DC current as well as AC)
Pg 108 - NZ switchboard location notice locations shall comply with NZ Building Code
Pg 117 - Ambient temperatures to use when calculating current carrying capacity using AS/NZS3008 
Pg 136 - "This information can also be found in NZS3604"
Pg 147-8 - Other standards to refer to when looking for fiddly details for separating services
Pg 187 - In NZ, you can't permanently wire in a freestanding, not built in cooker
Pg 190 - Extra requirements for electrical heating cables in NZ
Pg 207 - Telecoms Reference Conductor specs are in AS/ACIF S009 for Australia
Pg 217 - Minimum earthing stake penetration (NZ ones go deeper/longer)
Pg 236 - Telecoms standards numbers again
Pg 242 - Zone 1 height for over a bath with a shower in it (NZ is 0.25m lower)
Pg 310 - High voltage installations
Pg 313 - Standards for electrical fitout on boats in Australia
Pg 326 - Labels for RCDs in NZ 
And that's all I could find in all 458 pages of AS/NZS3000.  17 mentions.  Squidging them all together would give you two pages of text, maximum.  That's 0.004% of the content.  Less, if you take out the silly stuff.   
About the only one that would even vaguely concern me is the Zone 1 height for baths, but considering I am sitting not three meters away from a GPO (installed by an Australian licensed sparky) that is too close to a basin to conform to Australian (or even the identical New Zealand) standards, precision in complying with wet area exclusion zones doesn't seem to be an area of concern in the industry, so I'm not going to be too precious about it either.

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## oldtrack123

Hi Ransome 
Yes, those you listed  may be the only differenceS!!
But  that short reworded extract link hardly give a DIYer ALL the applying rules Or do NZers not need to know them?? :Roll Eyes (Sarcastic):  
I am not just talking about the differences & am talking about ALL the other applicable rules that  one requires the FULL standard
I see nothing about points per circuit, Calcs of max demand, loop impedance, & the list goes on
 Incidently , perhaps that power point went in a long time ago, before the current distances were set  :Roll Eyes (Sarcastic): 
PeterQ

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## Random Username

No, they _are_ the only differences in AS/NZS3000 until you provide detailed proof otherwise, not just speculation. 
And the power point that is incorrectly installed went in just over two years ago, so yes, it is wrongly located for the applicable standard. 
With the NZ DIY, I'm working on the assumption that the government body that is responsible for electrical safety in NZ probably has more of a grasp of what the 'absolute amateur electrician' needs to know than I do, seeing as it's their day job. 
It covers all the usual sort of stuff that a handyman would need to know, and if you more than glanced at it you'd see that yes, it does cover points per circuit, wire sizes, underground cables, lighting and power schematics, IP ratings, clearances for recessed lighting and some other handy to know things.   
It may not cover them in a 'this is how you calculate demand on a circuit', but I don't think someone who is replacing a power point really needs to know that - in pretty much the same way I don't think a sparky recalculates circuit demand when running an extra power point on an existing standard circuit - it's just 'grab some 2.5mm and run it'. 
Anyway, if people want the Australian Standards (3000, 3008, 3017, 3080, 1680, 3018 and so many more I can't list all 156 megabytes of 'em) there's always the aus communications torrent. 
I always love debates like this, as every time I have one, there's a spike in downloads via my sig link; just today (17th) there's been 15 downloads, five times as many as the previous day! I recon it'll be over 4,000 downloads before the end of its first year!

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