Dedicated Circuit Advice

[Zaphod Beeblebrox]

On 29/08/2018 at 11:29 PM, kelossus said:

Do you think there is any issue with the 6mm cable feeding the house from the mains for a starter?

No. 6mm CSA is plenty, unless you are running some serious machinery, or an instant hot water system. 

 

On 29/08/2018 at 11:29 PM, kelossus said:

 

From the fusebox to the mains tap on my roof there would be roughly a 5 meter run.

 

The fact my house only has a 6mm feed vs 16mm in modern houses may or may not be cause for concern?

Nope.

[frankn]

I also have long cable runs - it’s hard to quantity the difference between dedicated circuits and common circuits. It depends how much is hanging off the common circuit, whether you have issues with power supply or not, many people say Australia doesn’t have a serious issue (except perhaps WA). 

All circuits go back to the main supply in the Fuse box/Main power board so they are common - if you have single phase  supply it’s impossible to seperate. If you have 3 phase power then it is very unusual to have a circuit on a single phase that is dedicated to audio as the electrician will balance the entire household load across all phases. I think the best outcome is adding the dedicated circuits to the phase that is least heavily loaded. E.g if possible don’t have the kitchen / oven / heavy loads attached to the same phase.  Talk to your electrician about getting the load optimised for your audio circuit(s).   If you have 3 phase power for A/C or running other heavy duty units you can’t do anything about that. 

 

At at the end of the day, I think it’s about peace of mind. You have done your best for a reasonable $$ outlay. 

What you do is limited by your budget,  the inherited situation & regulations allow you to do. 

For me, I haven’t been arsed to try to compare power by plugging in my system to a non-dedicated circuit and evaluate. I also use  power regeneration on top of the dedicated circuits so who knows. 

My system sounds very good, highly resolving and lots of enjoyment. FWIW Vistitors (lots from SNA) tell

me it’s one of the very best in SA. 

[Anthony1]

Some auto suggestion as it wasn’t mentioned:
Isn’t it best that each dedicated HiFi circuit has its own earth spike as close as possible to the GPO.

[frankn]

Can be difficult to achieve the star type grounding that I think you mean. Proper star grounding is supposed to have a minimum spacing between each ground pole, and have a minimum depth. 

You are better off having a single very good ground rather than several not so good grounds. 

[Buddy No.3]

I was kinda pushing for a 32 amp circuit but I think 20 amp circuits would suffice. I was just imagining have two huge Krell Monoblocks and wanting a larger circuit for them. Will likely never materialize though.
 
The main concern for me is the 6mm mains. I would really like to change it to 16mm, in line with current homes but having to move the meter boxes is a pain in the arse. Was hoping a sparkie on SNA would inform that their is no need/obligation to move the meter box or that 6mm from the mains would be enough. I doubt the latter though.
 

Hi, I just went through this exercise myself less than a month ago.

I too was considering running dedicated 20amp or 30amp circuits for my Krell monoblocks because that’s what the manual recommended. However in taking with the Krell distributor they correctly pointed out that the manual is referring to USA power running at 120 volts whereas we’re fortunate to have 240 volt AC and therefore you just need to do the math to work what is the maximum power draw at peak output of your amps to work out what you need.

From the manual the maximum peak power for each monoblock is specified as 3,600 watts. We have to allow for a variance of +/- 10% in our 240V supply in Australia, which is 215 - 265 volts, so the maximum current draw will be between approx. 13 and 16 amps (Power = Current x Voltage).

This means I was fine with a 15 amp circuit as the chances the voltage will drop that much at the same time the amplifier is running at peak capacity would be near impossible.

So I installed 2 seperate 15amp circuits (one for each mono lock) and an additional 15amp circuit in case I ever need one for a power conditioner or other component and also a seperate 10amp circuit.

I figure this should have all components covered.

I’m now on the search for after market power cables that are rated at 3600 Watts.

Hope this helps.

Cheers

[kelossus]

Just an update. Sparky is coming next Wednesday to do the job. Costing $1350 in total and this includes:

 

2x 20amp Circuits run in 4mm. 3x Dual Gang Auto Switch Clipsal GPO's.

Two new 16mm drop wires from the mains to replace my 6mm mains.

Install an earthstake as the house is currently earthed of the mains water.

 

I am quite happy with the price.

 

Edited September 5, 2018 by kelossus

[almikel]

possibly a bit late to this discussion, but I'm dubious of any benefit of running multiple circuits as long as the current draw is safely within what 1 circuit can support.

The reason I say this, is if you have any earthloops in your gear, they will be exacerbated by traversing back to your switch board and back to the room.

 

Better to have a single circuit of ample supply and keep any earthloops in the room.

 

Sure well designed gear should not have earth loop issues, but they are a pain to track down and fix, and why make them potentially worse with multiple circuits?

 

cheers

Mike

[Primare Knob]

Is the max power draw from your equipment not a bit unreasonable to calculate the required fuse and cable thickness. I am running a complete HT setup with multiple power amps and subwoofers of a single 16amp circuit without tripping anything.

[andyr]

On 05/09/2018 at 6:07 PM, kelossus said:

Just an update. Sparky is coming next Wednesday to do the job. Costing $1350 in total and this includes:

 

2x 20amp Circuits run in 4mm. 3x Dual Gang Auto Switch Clipsal GPO's.

 

Sounds good.  But why only 3x dual GPOs - why not put, say, 4x dual GPOs on each 4mm circuit?

 

On 05/09/2018 at 6:07 PM, kelossus said:

Two new 16mm drop wires from the mains to replace my 6mm mains.

 

That should be great - and will remove any doubt that you would probably have had, if you had kept your original 6mm.

 

On 05/09/2018 at 6:07 PM, kelossus said:

Install an earthstake as the house is currently earthed off the mains water.

 

Can only be a benefit! 

 

3 hours ago, almikel said:

possibly a bit late to this discussion, but I'm dubious of any benefit of running multiple circuits as long as the current draw is safely within what 1 circuit can support.

The reason I say this, is if you have any earthloops in your gear, they will be exacerbated by traversing back to your switch board and back to the room.

 

Better to have a single circuit of ample supply and keep any earthloops in the room.

 

Sure well designed gear should not have earth loop issues, but they are a pain to track down and fix, and why make them potentially worse with multiple circuits?

 

cheers

Mike

 

For my new house (which we moved into almost 3 years ago), I specified 13 separate circuits (with single GPOs) for my "hifi room" - so 1 circuit for each component.  These 13 circuits are on 1 phase - the only other item on this phase (which forced us to have 3-phase power) is the lift ... so when the lift is not in operation, nothing else shares this phase.

 

I can assure you this "works" - ie. there is absoloootely no hum from earthloops.

 

Whether this produces a better sound than if I had just one circuit for all 13 components ... is a moot point!    But with a new build, it's a marginal cost increase - and it stops me from wishing, down the track, that I had done it when I had the chance!    And it might even produce better sound ... by separating power amp power draw from source component power draw.

 

Andy

 

[kelossus]

8 minutes ago, andyr said:

 

Sounds good.  But why only 3x dual GPOs - why not put, say, 4x dual GPOs on each 4mm circuit?

Hi Andy

 

1x Dual GPO for one circuit. This circuit will be my power amplifier/monoblocks/integrated amplifier circuit only.

 

I have a lot of Nordost gear so any spare outlets will have either a QX4/QV2/QK1 in any unused outlet.

 

2x Dual GPO's or possibly 1x 4-Gang GPO for the other circuit. I will only really use one outlet to connect my Qbase powerboard. This circuit will be for a preamp (if I don't go integrated) and a phono stage. A CD player too but not for critical listening.

 

Again any unused outlets will be have the nordost gear plugged in. I may add stereo subwoofers at a later date as I have pair here.

 

It really depends on once I get the room up and running and measured. Will take it from there afterwards.

[almikel]

On 08/09/2018 at 6:48 PM, andyr said:

the only other item on this phase (which forced us to have 3-phase power) is the lift

is the lift motor 3 phase? - I love 3 phase stuff - there's an elegance in the concept of 3 phase star/delta connected kit - or was it just load that forced the 3 phase upgrade and you went single phase with the lift?

 

In our last house I upgraded to 3 phase because it didn't cost much to do so.

With AC and a bunch of serious pool pumps for a "swim jet" a single phase was "sort of" approaching the limit of a single phase...but I upgraded to 3 phase mostly because I wanted to...

 

After installing 3 phase power my sparky questioned why I wanted a 3 phase power point installed - easy answer - because I could...

..I had plans for building 3 phase power amps just because I could (way less ripple after rectification) - but then we sold the house ...

 

On 08/09/2018 at 6:48 PM, andyr said:

I specified 13 separate circuits (with single GPOs) for my "hifi room" - so 1 circuit for each component

I'm sure your sparky was delighted and bemused all at the same time.

On 08/09/2018 at 6:48 PM, andyr said:

the only other item on this phase (which forced us to have 3-phase power) is the lift ... so when the lift is not in operation, nothing else shares this phase.

In a household situation no doubt the lift is not used much - but a lift motor is like a fridge or a pool pump on steroids with major load variations with starting and stopping...

 

...If it's a 3 phase lift motor you have no choice, the load is across all phases...

 

...If the lift motor is single phase it's an interesting choice you've made for the lift to share the same phase as the power for the stereo room for someone that chose to run 13 separate circuits for their stereo room...

...With decent audio gear, I would expect the lift operation to make no difference that I could hear, even with lift high voltage relays clicking in/out and the motor starting/stopping...but I would also expect to hear no difference between 1x240V circuit that meets amperage requirements vs 13 separate circuits...

On 08/09/2018 at 6:48 PM, andyr said:

there is absoloootely no hum from earthloops.

Unfortunately I've had numerous bits of gear that were sub-optimally designed - in both consumer gear and pro gear scenarios, that when added to a quiet system, introduce a hum via an earth loop.

 

You're very lucky if you haven't experienced this.

 

If you were unfortunate enough to add a bit of kit to your system that was sub-optimally designed and it created an earth loop - be assured the hum will be way worse if the loop goes via your main switch board rather than via the earth pin in the room.

 

Mike

Edited September 9, 2018 by almikel

[andyr]

7 hours ago, almikel said:

is the lift motor 3 phase? - I love 3 phase stuff - there's an elegance in the concept of 3 phase star/delta connected kit - or was it just load that forced the 3 phase upgrade and you went single phase with the lift?

 

The lift motor has a feed from all 3 phases, Mike.  But when it's not in use, there's no "lift draw" on the hifi phase.

 

7 hours ago, almikel said:

If you were unfortunate enough to add a bit of kit to your system that was sub-optimally designed and it created an earth loop - be assured the hum will be way worse if the loop goes via your main switch board rather than via the earth pin in the room.

 

Mike

 

There is a sub-switchboard for just the 13 circuits, in the 'hifi room'.

 

Andy

 

[almikel]

On 10/09/2018 at 6:32 AM, andyr said:

There is a sub-switchboard for just the 13 circuits, in the 'hifi room'.

that makes sense - down the track if were unfortunate enough to get an earth loop it would stay in the room.

 

On 10/09/2018 at 6:32 AM, andyr said:

The lift motor has a feed from all 3 phases

very cool.

Did you get a 3 phase power point installed somewhere just for Ron? 

 

Mike

[andyr]

53 minutes ago, almikel said:

Did you get a 3 phase power point installed somewhere just for Ron? 

 

Mike

 

No, I don't think so.  But who/what is 'Ron'?

 

Andy

 

[frankn]

LateRon ???

Edited September 11, 2018 by frankn

[almikel]

On 11/09/2018 at 9:37 PM, andyr said:

 

No, I don't think so.  But who/what is 'Ron'?

 

Andy

 

 

On 11/09/2018 at 10:46 PM, frankn said:

LateRon ???

yes - "later on" - sorry - old school rhyming slang

Edited September 13, 2018 by almikel

[frankn]

4 minutes ago, almikel said:

 

yes - "later on" - sorry - old school rhyming slang

I knew exactly what you meant. My old man was a Londoner. 

[andyr]

22 minutes ago, frankn said:

I knew exactly what you meant. My old man was a Londoner. 

 

Not 'Londoner' - "cockney"!    My old man was born within the sound of Bow bells!

 

Andy

 

[frankn]

Actually @andyr cockney rhyming English (slang) was in use all over London and into the suburbs in early 19th century. 

It is associated with the language of the working class in and around London. 

I know exactly what defines a cockney since a number of my extended family “qualify” - with a number still living there. 

I use the term Londoner as per the song:

 

Maybe it's because I'm a Londoner
That I love London so
Maybe it's because I'm a Londoner
That I think of her wherever I go
I get a funny feeling inside of me
Just walking up and down
Maybe it's because I'm a Londoner
That I love London town

Maybe it's because I'm a Londoner
That I love London so
Maybe it's because I'm a Londoner
That I think of her wherever I go
I get a funny feeling inside of me
Just walking up or down
Maybe it's because I'm a Londoner
That I love London Town

 

 

[Zaphod Beeblebrox]

On 04/09/2018 at 4:00 PM, Anthony1 said:

Some auto suggestion as it wasn’t mentioned:
Isn’t it best that each dedicated HiFi circuit has its own earth spike as close as possible to the GPO.

No.

[Anthony1]

Zap, what are you saying ‘no’ too?

a) that a dedicated HiFi circuit doesn’t need a dedicated earth ?
Or
If you decide to have 2 dedicated circuits adjacent to one another then 1 earth spike is sufficient ?

[Zaphod Beeblebrox]

18 minutes ago, Anthony1 said:

Zap, what are you saying ‘no’ too?

a) that a dedicated HiFi circuit doesn’t need a dedicated earth ?
Or
If you decide to have 2 dedicated circuits adjacent to one another then 1 earth spike is sufficient ?

All the above. Power point earths, in Australia, are all run back to the switchboard, to a common earth (MEN system). ALL qualified electricians know how to run such a system to meet with the appropriate regulations. Over-thinking and over-complicating the mains power is not necessary.