AC house wiring

[carlmart]

I'm modifying my apartment, and everything will change. One if them is the AC wiring.

Where I live (Brazil) we have what we call 3-phase wiring, that is we have three live wires and a ground. Combining one live and one ground wire you get 110v, if you combine two live wires you get 220v.

On my past two houses I assembled it in such a way where I would put all high-current stuff (washing machine, fridge, etc.) on one wire, computer on a second and audio/TV on a third. AC units are 220v over here, so I would wire them accordingly, on separate protection switches.

There's some advise I would be grateful to have on two matters at least:

1) What wire gauge should I use for the audio/TV wiring?

2) As I am considering buying my wall apppliances in the US, what brand and type would you recommend? Any best place to buy them?

Thanks,


Carlos

[zigzagflux]

You may have your terminology off a little. You say you have three phase, but the system of 110/220 you describe is split single phase. Both of these systems are 3 wire plus ground (with some three phase systems being 4 wire plus ground). A three phase system will have line-neutral (ground) voltages differ from line-line voltages by 1.732. So a three phase system would be 120/208, not 110/220. So the first thing you need to do is resolve what you actually have to work with.

That being said, your general best bet is to load your system in a balanced manner, which is better for voltage drop and better for the utility grid. So putting all high current loads on one leg sounds good, but doesn't really provide any benefit for your audio system. There are advantages to placing sensitive loads on their own breaker, or in the extreme using an isolation transformer for that circuit, but we're talking an apartment here (which to me implies renting).

As far as wire gauge, just follow the NEC. An A/V system does not draw that much power, such that an increase in wire size will significantly affect operation. If you are dealing with a 500 foot run let's discuss.

Appliances, a can of worms. All I can say is avoid Viking like the plague. Worst quality and customer service, although you pay three times as much for the same hardware.

[carlmart]

Thanks for your advice.

Originally Posted by zigzagflux

You may have your terminology off a little. You say you have three phase, but the system of 110/220 you describe is split single phase. Both of these systems are 3 wire plus ground (with some three phase systems being 4 wire plus ground). A three phase system will have line-neutral (ground) voltages differ from line-line voltages by 1.732. So a three phase system would be 120/208, not 110/220. So the first thing you need to do is resolve what you actually have to work with.

My terminology is not off, it's the way it's called here. It's called trifasic. Maybe it's what it's called split single-phase in the US. Trifasic started as an industrial application use, then passing on to home use.

That being said, your general best bet is to load your system in a balanced manner, which is better for voltage drop and better for the utility grid. So putting all high current loads on one leg sounds good, but doesn't really provide any benefit for your audio system. There are advantages to placing sensitive loads on their own breaker, or in the extreme using an isolation transformer for that circuit, but we're talking an apartment here (which to me implies renting).

Not, it's not rental, we own it. In a rented house you can not do what I intend to do, which is destroying the whole apartment.

Some load will be on separate breakers, like air-conditioners, but not the rest. What I will try to provide are separate breakers to audio, TV and computer.

What I do not want is noise or spikes coming from home appliances polluting those more sensitive lines, or RFI coming from the computer affecting audio/TV AC lines.

As far as wire gauge, just follow the NEC. An A/V system does not draw that much power, such that an increase in wire size will significantly affect operation. If you are dealing with a 500 foot run let's discuss.

Where do I get the NEC table?

The apartment is 110 square meters, and I don't know much how that is in US feet. By my counts I shouldn't exceed 100 feet for any wire run, I think, maybe 200 Ft..

Appliances, a can of worms. All I can say is avoid Viking like the plague. Worst quality and customer service, although you pay three times as much for the same hardware.

I was considering Pass & Seymour or Hubbel.

[Speedskater]

"NEC" is the US National Electric Code. 2008 is the current version but 2011 will be out soon. This rule book is well over 800 pages long. Most of can be found searching the web.

Jim Brown of Audio Systems Group (also a AES committee chair) recently released an international version of his paper on audio systems and AC power.

http://www.audiosystemsgroup.com/SurgeXPowerGround.pdf

[zigzagflux]

Originally Posted by carlmart

My terminology is not off, it's the way it's called here. It's called trifasic. Maybe it's what it's called split single-phase in the US. Trifasic started as an industrial application use, then passing on to home use.

If that's the case, you either have 110/190 or 127/220. It's not that I insist you have single phase, I'm just saying three phase (triphasic) 110/220 is impossible, no matter where in the world one lives. The numbers point to single phase, while your description points to three phase.

I was considering Pass & Seymour or Hubbel.

LOL. Sorry. I was assuming you were talking about refrigerators and stoves. Yes, P&S or Hubbel are very good choices.

[dudaindc]

Originally Posted by carlmart

...
The apartment is 110 square meters, and I don't know much how that is in US feet.
...

Approximately 1100 square feet - 1184 ft2 to be more precise.

[AndrewT]

Originally Posted by dudaindc

Approximately 1100 square feet - 1184 ft2 to be more precise.

precise indeed, error less than 26ppm.

[jean-paul]

Originally Posted by Speedskater

"NEC" is the US National Electric Code. 2008 is the current version but 2011 will be out soon. This rule book is well over 800 pages long. Most of can be found searching the web.

Jim Brown of Audio Systems Group (also a AES committee chair) recently released an international version of his paper on audio systems and AC power.

http://www.audiosystemsgroup.com/SurgeXPowerGround.pdf

A good read, thanks !

[dudaindc]

Originally Posted by AndrewT

precise indeed, error less than 26ppm.

[carlmart]

Originally Posted by zigzagflux

If that's the case, you either have 110/190 or 127/220.

Yes, you're right. It's 127/220v.