I am building out a dedicated listening room in a house we just purchased. There is a dedicated 200 amp breaker box for a hot tub we are getting rid of. So, I will have this breaker box deducted for a listening room. Assume i have a rig with mono blocks (ss), multichannel amp (ss) ,pre/pro, universal disc, dac, large led tv, cable box, distributed audio/video controller (control 4). The room is in the basement not very far from the breaker box (running lines would not be a problem). Also, the walls will be opened for the renovation so adding outlets and running wire not an issue.
I have read many of the threads on the subject here and am often confused by conflicting info and partial advice
So, what I would like is for any friends out here to put yourself in my shoes and imagine you are telling the electrician (who from what I have read will typically be amused and a bit confused by the Audiophile focus and perhaps not the best source of advice) what to do. So, would be great if the post is you imagining you are speaking to the electrician and saying. "ok, here is what I want you to do ......"
Assume I want to do it right and legally (so no non code separate grounds).
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.
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.
If you are going to put in multiple circuits, make sure that all those connected with interconnects are on the same side of the phase. Balance the load by put everything else on the other side of the phase. You may want to provide him with special wall outlets.
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!
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. Cheap insurance.
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.
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.
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.
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, thatÂ’s just what you will get.
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.
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.
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? 10-have fun!
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.
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