I had the same situation and put in 4-20 amp dedicated lines...3 for Analog and 1 for Digital..Best upgrade I ever did...
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I suggest the dedicated 20A circuits have an isolated ground from the rest of your household AC.
Also, if you have room, consider installing an isolation transformer at or near the service panel for the dedicated audio circuits. I have not done this due to several factors that make it prohibitive, but if the location of our service panel lent itself to installing a large isolation transformer, I'd likely do it.
Lots of opinion on this topic, but on a basic level almost everyone agrees on dedicated 20A circuits and isolated ground.
also tell them to be careful, do not nick the copper when removing insulation, be sure to use the correct gauge wire, 10 is good...you can use a separate ground, as suggested above. If you want the ultimate AC upgrade, have solar put in. It gets your AC from the local star, you would not believe the difference when listening in mid-day! off the grid is an unbelievable experience.
A caveat to the isolated ground suggestion...
Since isolated ground requires isolated ground receptacles in addition to the isolated ground wire, you will be precluded from installing the fancy, shmancy aftermarket audiophile outlets since none are the isolated ground type (as far as my search has revealed).
In my system, the isolated ground circuit with the accompanying service grade Pass and Seymour isolated ground receptacles has resulted in a quieter system than when I had the non-isolated ground circuits with cryo'd Hubbell hospital grade receptacles.
1-get full size electric boxes, some of the renovation size ones are too shallow.
2-have him run any cat-5 and/or cable runs that you may need.
3-have him pull cable for the tv or projector. You can have this terminated in boxes even?
4-don't let them close up the walls until you check it out.
5-make sure that any lines that have to cross do so at 90 degree angles.
6-I would run non-electrical wiring at a different height to avoid touching power lines.
7-New drywall? Double layer, staggered seams on the outer layer, soundproofing around any junction boxes...
8-What kind of lighting?
9-are you having the surround wiring put inside the walls?
Surge protection at the service panel.
Also have your electrician check the outside ground to the panel...by luck my house had two. One at the panel and another further down from the panel. Check the AC noise once everything is installed as value added.
If I had a "do over" surge protection and filter at the service panel.
Make sure all breakers are wired in phase.
Also the grounds between circuits must be at exactly the same potential.
With dedicated lines you can have a ground loop when you hook up different devices together which span the different circuits.
I recommend that the projector circuit is a junction off of the main circuit used for the surround processor, this will eliminate the chance of ground noise in the picture.
Hubbel hosipital grade outlets are cheap and very good.
Make sure all circuits are 20 amp and use the heaviest gauge you can get.
BX cable is better than romex due to the bx's metal shield.
If you run any signal cables run them at 90 degree crosses over any electrical lines and keep cables at 6 inches or further from any ac lines.
A missed thing is cooling and heating a proper theater room will have an ambient noise floor of less than 50db, the quieter the room the better, split ducless ac units are great, central air can be great but the ducting must be of adequate size with an optimal number of bends to slow down the air velocity to create quiet cooling.
Hire a licensed Contractor! Call your local contractors association or board and check up on them. Make sure all the electrical work is performed by a journeymen not some guy who says he know what he doing. In most cities this type of remodel work requires a permit and inspection. Please remember if you want it cheap, thats just what you will get.
Sound like a fun project. Good Luck.
Make sure your electrician follows the National Electrical Code (NEC). Don't do
things that will violate NEC even if someone tells you it may sound better.
Safety should always come first. Some electricians will do anything you tell
him. So make sure you ask him if what you want will violate NEC. If he is not
sure, hire someone else.
Isolated Receptacles. Where installed for the reduction of electrical (electromagnetic interference) on the grounding circuit, a receptacle in which the grounding terminal is purposely insulated from the receptacle mounting means shall be permitted. The receptacle grounding terminal shall be connected to an insulated equipment grounding conductor run with the circuit conductors. This equipment grounding conductor shall be permitted to pass through one or more panelboards without a connection to the panelboard grounding terminal bar as permitted in 408.40, Exception, so as to terminate within the same building or structure directly at an equipment grounding conductor terminal of the applicable derived system or service. Where installed in accordance with the provisions of this section, this equipment grounding conductor shall also be permitted to pass through boxes, wireways, or other enclosures without being connected to such enclosures.
FPN: Use of an isolated equipment grounding conductor does not relieve the requirement for grounding the raceway system and outlet box.
One example of how to use two 5 KVA isolation transformers. These two isolation transformers go from my main AC panel to my sub-panel and power three different sound systems in my home.
There are whole-house surge protectors available. I'd install one.
These are not MOV type which have a lifetime, but rather another technology which doesn't wear out.
For short runs, I'm sure that 4x20amp, 12 ga. will suffice.
Small isolation transformer is good for low current stuff. I use one as part of my Panamax power conditioner and it is great. and only a 400va unit.
Buy a 'Kill-a-Watt' power meter so you can measure voltage drop, current used and most importantly, Power Factor. The meter? about 25$ and is quiet the bargain. I use my as a tool, NOT for permanent installation.
I'd need a stethoscope to hear this tranny. The Panamax is way heavy and silent.
The fan in the bathroom makes more noise at my seating position.....or even the 'fridge in the kitchen.
Know what you mean, though. Late at night, especially, stuff you can't hear during the day becomes quite annoying. But not that iso trans!
200 amp panel board for a hot tub? WOW! Usually this size panel board can run an entire house.
1. Make sure the 200a PB is fed properly. Minimum #3/0 feeders and neutral. And, most importantly, a MINIMUM of #4 ground back to source where this sub panel is fed.
If, in fact this is a sub panel... I'm guessing it is, the ground and neutral must be isolated from each other. And tell your electrician to check your main bonding and main ground at your source... make sure they are properly installed and have little resistance to ground. If the electrician seems confused... get a different electrician.
2. Most likely, the install will be with #12 romex. If the panel is more than 100' away use #10 for voltage drop. The boxes in residential are usually plastic or fiberglass attached to wood studs. If you are dealing with wood studs and non-metallic boxes... you have no need for isolated grounding.
3. If you are using fluorescent bulbs in your home, do not feed them from this panel! If possible, throw them all in the trash.
4. Isolation transformers are an extreme measure, especially since you already have some isolation with a sub panel. Transformers buzz and vibrate... eventually.
5. You can attach a surge suppressor to the panel.
6. Good quality hospital grade receptacles are adequate. Your electrician can get these for you.
7. Multiple paths to ground are BAD! Make sure the electrician understands this theory. Get the project inspected by the local authorities... talk to the inspector while onsite. Ask the inspector to check grounding. Grounding is the most important item in electrical... along with everything thing else...;)
I am a licenced electrician with 27 years experience, 5 years apprentiship.
I have been Supervision for the last 20... I have overseen Major projects such as Hospitals, Waste Treatment, Manufacturing and now Coal Burning Power House Installations. But, I started in residential.
Most importatantly... a practicing audiophile.
Best of luck with your project,
Excellent ideas, all of the above.
One addition is to ensure your circuits which feed any computer equipment are also served by armored cable (BX). The noise emitted by NM (Romex) with computers attached is terrible.
The idea of using #10 BX is a good one, but limit the circuit breaker to the rating of the receptacle (20A).
Isolation transformers serve best when connected phase-to-phase on the primary side (240V) avoiding the polluted neutral connection filled with harmonics. The secondary should be center tapped, for your equipment.
This creates a separately derived system; one which must be grounded as well. However, this ground, while connected to all available grounding electrodes (typically cold water on the street side of the main water shutoff, within two feet of the entry of the water pipe to the house) and a supplemental grounding electrode (ground rod), will be an independent connection for the derived neutral on the isolated system. This method means least electrical noise intrusion into the isolated system. BUT, it also means providing a distribution system with overcurrent protection for the derived circuits. In other words, use the transformers to feed a circuit breaker subpanel.
If your electrician doesn't immediately understand exactly what I've written above, run away fast and find a new one.
Best of luck,
Maryland State ME #7461
This creates a separately derived system; one which must be grounded as well. However, this ground, while connected to all available grounding electrodes (typically cold water on the street side of the main water shutoff, within two feet of the entry of the water pipe to the house) and a supplemental grounding electrode (ground rod), will be an independent connection for the derived neutral on the isolated system. This method means least electrical noise intrusion into the isolated system.Sepolansky,
You are saying the neutral, (The Grounded Conductor), of the secondary winding of the xfmr has to be connected to the existing grounding electrode system of the main service of the premises, correct?