"Ideal" power line from Service Panel

[tryonziess]

speedskater,
Along with following the national electrical code to the letter for your project I would install a totally separate, isolated earth ground. The standard NEC ground is a 10 foot long rod driven into the earth where all of the grounds eventually terminate.
For your audio room you can install a single separate ground going to a 10 foor copper rod driven into the earth as close to the audio room and as far away from the house panel.
I have this setup and I get zero transients from any electrical apparatus in my home. No hum, buzz, static just nothing on the ground side.
The power side is a lot more complicated. The isolation transformer is a good place to start. The hot side is much harder to completely isolate aside from using batteries.

Tad

[Printer2]

So I took a quick look and see you are running a 200w amp and will possibly running a second. A dedicated circuit in your panel is not a bad idea. Everything else sounds like a waste of time and money.

The transformer, as was said before just a way of raising the supply impedance to your components. The direct connection to the utility system through your service panel will give you more instantaneous capacity. In an industrial setting you have to fuse for the interrupt capacity of the circuit, sticking a transformer (one to one transformer) between the bad boy outside reduces the size of the fault current. Other than making you feel you have something special you are worse off.

Running your power lines in a pipe, plastic, copper, steel, what is the point? Do you know why you are doing this? It will in no way add or subtract to the quality of the power you will have.

Plug all your components into one point to eliminate the problem of ground loops.

Solid core, stranded wire, it makes no difference. Use standard 12 gauge wire and be done with it. With the length of the run you have any more will not have an effect. Just more of a pain to hook up. Ohm's law is your friend.

You do not need anything special wire. Forget skin effect, capacitance, all the other reasons for different wires. You are transmitting 60Hz after all. The wavelength is so long you will not get any transmission line effect, any other exotic reasons you can think of.

Get a good surge arresters, if you want to spend some money get a whole house one and install it in your panel. Then put a secondary surge arrester at your components. This should kill any spikes that come down the line.

Not to be contrary but did you have problems with your stereo before that makes you want to take all these actions? Your home is not a harsh environment and what gets thrown to your components should be easily handled by them. Run cabling for sensors for hundreds of feet in industrial environments is a different story. Might be time for a little sanity check.

[Jim Leach]

Hello, Tad.

I believe a single earth ground is all that is permitted for a single-service installation, and it has to be as close to the service entrance as possible.

I think someone mentioned earlier it plays havoc with GFI protected circuits when I mentioned the ground rod and they thought I was planning to do what you are suggesting (add a second ground rod).

However, I will mention that all our robot installations have an earth ground rod next to each robot, and we also have one on our grit blast cabinet to dissipate static charge. These were installed by the electrical contractors, so I guess there are cases where it is permitted... (but that is an industrial installation, not a home). Also the CNC machining centers have them as well I just remembered.


Attached are pics of the 'beast'. Seems to have a large transformer and 4 good sized caps... Star ground inside too! I'll gut the outlets out of it and probably just make a new end panel with two penetrations: in and out...

[star882]

The presence of the big capacitors suggests that it is a ferroresonant transformer. It should work well for regulating voltage. Just install a switch so you can turn it off when not in use as the standby losses are probably significant.

[scid714]

the best is to have a say maybe a 25 kw ups system with large wet cell batterys. battery filters power like nothing else. and isolates your system from outside spikes brownouts ground noise ect...

[Speedskater]

Originally Posted by tryonziess

speedskater,
Along with following the national electrical code to the letter for your project I would install a totally separate, isolated earth ground. The standard NEC ground is a 10 foot long rod driven into the earth where all of the grounds eventually terminate.
For your audio room you can install a single separate ground going to a 10 foor copper rod driven into the earth as close to the audio room and as far away from the house panel.
I have this setup and I get zero transients from any electrical apparatus in my home. No hum, buzz, static just nothing on the ground side.
The power side is a lot more complicated. The isolation transformer is a good place to start. The hot side is much harder to completely isolate aside from using batteries.

Tad

Not only is that against NEC / CEC rules, it's very dangerous!

Look through the papers that I posted links to at the start of this thread (post #2) and see if any of the paper recommend a separate ground rod.

[SoNic_real_one]

It is amazing how many "know it all" are on this world - that give advises without bothering to read first a few links.
It is dangerous and banned by local and NEC codes to install a separate ground rod. Also it doesn't improve nothing in the audio power supply - the "pops" are coming from shared neutrals, undersized wiring, bad/old joints in the electrical path (like the in-out from the old receptacles).

Also suggesting USP systems for audio systems - that urban legend keeps popping everywhere on the net perpetuated by people that have no clue how an UPS is working and how "dirthy" is the output voltage.
What's next?

Originally Posted by star882

The presence of the big capacitors suggests that it is a ferroresonant transformer. It should work well for regulating voltage.

It might regulate the voltage, but if you read about how they are really working you will find out that are deforming the sin wave (therfore creating harmonics) and also there are terible slow to react to transient loads. Not what you want for an amplifier power supply.

[scid714]

Originally Posted by SoNic_real_one

It is amazing how many "know it all" are on this world - that give advises without bothering to read first a few links.
It is dangerous and banned by local and NEC codes to install a separate ground rod. Also it doesn't improve nothing in the audio power supply - the "pops" are coming from shared neutrals, undersized wiring, bad/old joints in the electrical path (like the in-out from the old receptacles).

Also suggesting USP systems for audio systems - that urban legend keeps popping everywhere on the net perpetuated by people that have no clue how an UPS is working and how "dirthy" is the output voltage.
What's next?

It might regulate the voltage, but if you read about how they are really working you will find out that are deforming the sin wave (therfore creating harmonics) and also there are terible slow to react to transient loads. Not what you want for an amplifier power supply.

well mister know it all i have never seen" dirthy" voltage. but if it is good enough to run the worlds network every piece of medical equipment a hospital could have i don't know. how else are you going to have a supply void of noise, spikes and other transiants without a really good battery plant and inverter system. it's electricity inherently dirty and not pure. please correct me if i am wrong.

[anatech]

Hi Jim,
Just one comment. Well, maybe two.

Use only a single ground point for your electrical system. Aside from single grounds being code, multiple grounds (or "technical grounds") don't normally work well. What will help would be to confirm that the existing ground is a good one, and that the soil is always moist (I can't imagine why that's important! ). What you could do if needed would be to install a rod deeper into the ground. That's the solution for a ground spike not well installed.

Some recording studios I have done work in did try to use "technical grounds". They were a fad at one time, but they didn't work. The only sites still like this are the ones that Ontario Hydro doesn't know exist. As far as worrying about the conduit material, don't. Just go to code. Any situation a home will be in will not be helped by using a shielded (or magnetically shielded) conduit. Filters at your equipment end will be the proper way to deal with that. Note that you can also get entry filters intended to be installed right at the panel. They are ULC / UL / CSA approved devices. Same goes for surge protection devices.

If you know of a maintenance person for AM radio stations, talk to them. They have instruments designed to test the ground quality of grounding systems. In fact, they need to confirm large area grounds for the antenna systems.

The ferro-resonant transformer you have there does not output a sine wave. You probably want to rethink that idea. And yes, the power loss is significant as well as the fact that they can be extremely noisy in operation. These are used mainly to regulate the AC voltage, not to isolate noise.

A good isolation transformer built on an EI core that includes an electrostatic shield would be the device you are looking for to block noise on the line. Your amplifiers should probably go direct if they are high power, your signal equipment can go after the isolation transformer. I can see this working to attenuate the possible electrical noise you may have.

I moved into a new house about 10 years ago now. I was allowed to do extra wiring myself before the walls were closed up. All I did was run a heavier gauge wire to a dedicated outlet for my sound stuff. I used that for the amplifiers, and the normal power installation for my signal stuff. Yes, they are on the same phase. Really, that's all that was needed in my situation. No high power radio stations or heavy industry around here.

-Chris

[Jim Leach]

OK. I guess the isolated ground and no transformer with #12 wire (maybe #10) is what the final solution is.

Anyone want a big heavy transformer?