Instructions to electrician about dedicated line

I just bought a Krell KAV-3250 and also am building a new house. What kind of specific instructions should I give to the electrician when he installs the 15 amp dedicated line. Krell recommends a 15 Amp line for the KAV-3250 amp. Is that all I need or should I ask for a 20 Amp line? Could I also hook up the receiver to this line?
If your going fro scratch. Put in a dedicated line for each component. As a bare minimum. Keep the digital seperate. Do not put any digital devices on any lines that will have PRE or amps or anything else.
Also keep amy Vidoe devices on seperate lines.
Dedicated lines are the best thing you can do.
Make sure you get a Electricain who gets it.Who knows what he is doing. Most have not a clue. They are wire pullers. Make sure you dont get a wire puller to do the job.
I'd go ahead and request three dedicated lines: Power amp, digital equipment and other (this assumes a cost of about $50-$75 per dedicated line). If you want a bit of insurance, you may wish to consider two to three more: Future second mono amp, TV / video (if that is in the same area) and analog if you are considering going there in the future. Unless there is an issue with the total fuse box capacity, the 20 amp circuit provides more future upgrade potential.

I am also building a house and have five dedicated lines at 20 amps each: Power amp about 5 ft left of center, power amp about 5 ft right of center and three circuits in the middle. I chose to go with 10 guage twisted solid wire (Southern Wire Co available at Lowes or Home Depot). I've left additional length (i.e., there is about 10 additional feet of wire between the outlets and fuse box) in the event I choose to go with a star grounding scheme later and add another ground rod. I'd love to go with ceramic fuses but am running into some code issues around that.

Search some prior posts -- there are a ton of them on the topic and there's lots of great advice. Look up "dedicated line". Good luck. Don't forget the outlets -- lots of good choices here too.
Should you install multiple dedicated a/c lines, be sure they are all "in phase" with each other. Your electrician will know this term. Be sure to use quality duplexs as well. They can really put the icing on the cake. Happy listening and good luck with your new home!
dedicated audio
I had the electrician install ten gauge wire and 30 amp breakers with 20 amp hospital grade receptacles. This is what I have done, but this was against the advice of my electrician, who suggested 20 amp breakers. Of course, I did a lot of searching on this discussion forum for more information that was helpful, but adding even heavier gauge wire to the formula is the only "twist" I can add to the extensive list of helpful tips listed on this site. Spend an afternoon searching.

Use up all the spare space on the panel. It seems you can never have enough outlets.

I also have added 2 category 5 wires and two rg-6 coaxial drops for every location you want to have stereo.
I agree that several dedicated 20 amp lines will give you versatility in the future. I recently had three 20 amp lines added for my audio/video equipement in our living room. Because the main panel from our house was over 25 feet from the equipment position and fairly full (no room for three circuits all in phase with one another) we installed a 60 amp subpanel in the basement under the living room, and ran the dedicated circuits directly to that (therefore much shorter run of wire to the subpanel than would have been necessary to the main panel). Use 10 gauge wire-- it'll sound better. And (for what it's worth) we had Cutler-Hammer whole house surge protectors installed on both main and subpanels. Avoids the need for point of installation surge protection (I use a Hydra, which does without) and adds peace of mind in thunderstorm season without (as far as I can tell) affecting the sound.
If you are starting from scratch, install a 100 amp sub-panel off of the main breaker box. You can then run as many 15 or 20 amp circuits as is necessary. I'd use 10 gauge for all the runs regardless of the amperage rating of the breaker. If possible, twisted pairs would offer additional noise cancelling and rfi protection. Stick with 15 amp breakers for line level components, digital components, etc... The only ones that would ever benefit from a 20 amp breaker would be a big amp that is being pushed hard. Using this approach, you could literally have four 15 amp lines and two 20 amp lines at your disposal. All of this on dedicated lines. Make sure that each outlet is wired with its' own hot and neutral with each sharing a common ground amongst them. Some electricians will run dedicated hots and share neutrals. Sean
If you can afford it, use BX and make it 10 ga.

Run 220 vac if you can to iso transformers for step down.

OR, use a single large ISO tranny in the basement to provide
local power... isolate each line with an RFI/EMI filter.

Put a big ass GROUND wire on your main service, and use
a real copper ground rod, have the earth prepared properly too.

MORE is always better in AC power.
Time out for a question!?!?!!!Does going with dedicated 20 amp lines allow for use of power conditioners like say PS Audio 600 or can they not use this much current?Thought I had read somewhere that these devices could not handle this amount of current but to do it anyway as dediucated lines would have greater impact on sound just don't waste $$ on conditioners latter?
As (almost) always great thread
Chazzbo, the current draw on a 20 amp line is a maximum of 20 amps (then the fuse blows). The actual current draw depends on the equipment being hooked up to it and will generally be much less than 20 amps in any typical home system. You are, I believe, correct in stating that the PS Audio 600 is not designed to handle the maximum amperage a 20 amp line can deliver (it translates to about 2200 watts). But it also won't be able to handel all the amperage a 15 amp line can deliver (about 1650 watts). That's OK so long as the equipment being hooked up toe the PS Audio 600 does not demand more than the 600 can deliver (BTW, you can still use the other outlet on a duplex plug for other things). Why get 20 amps? In my mind, for future upgrades only -- and probably for big power amps only. Sean makes a good point about mixing and matching on a dedicated subpanel.
What if you ever change amps? I put in a whole house surge protector as well. It prevents outside problems from interfering but will not protect you from inside trouble(ie feedback from your a/c compressor). For that reason, I also use a line conditioner/surge protector at the unit. I like using GFIs also.
The answer to the, "Why 15A or 20A circuits" is really a code question. The smallest wiring allowed by the NEC for a power circuit in a residence is 14 gauge with 12 gauge being common. Since a 14 gauge wire will carry 15A, it's typical to install a 15A breaker on a 14 gauge circuit. Likewise with 12 gauge and 20A breakers.

Sean's (and others') suggestion to use 10 gauge wire in a 20A circuit is to reduce voltage drop in that circuit. 10 Gauge wire will carry 30A and could have a 30A breaker installed in the circuit. From a power delivery standpoint (up to 20A, of course), this circuit won't be any different with a 20A or 30A breaker installed. However, one might be able to find a higher quality 20A breaker for the same price as a regular 30A breaker.

The thing to remember is that wire is sized to carry a load and the breaker is sized to protect the wire, not the other way around. So, while it's OK to install a 20A breaker in a circuit wired with 10 gauge wire (your electrician will look at you funny, but what does he know?), it is NOT good (or legal) to install a 20A breaker on a circuit wired with 14 Gauge wire.
Macdonj, thanks for clarifying why i stated what i did. In that respect, you were right on the money. However, i would like to add that i don't personally feel that 10 gauge is sufficient for 30 amp service. Regardless of what most "professionals" will tell you, 10 gauge will produce a very noticeable voltage drop under a 30 amp load if it is anything more than a few feet long. I have measured sizable voltage drops using 8 gauge at lengths of under 20 feet while trying to pull 30 - 35 amps through it. As such, i would consider 10 gauge "adequate" for a 20 amp load using the normal length runs that one might find in a house. 12 gauge should be considered minimum for a 15 amp circuit. That is, if one is looking to reduce series resistance / voltage sag to a minimum.

As i've mentioned before, i'm simply sharing / passing on my personal point of view based on the experiences that i've had. As such, my comments are worth just slightly less than what you paid for them : ) Sean
Bear: While i can understand your thoughts about using one BIG isolation transformer to feed the A/V breaker box for sake of simplicity, what are your thoughts on using multiple smaller ( 15 - 20 amps each ) yet identical transformers wired in parallel ? Sean
Sure, Sean, that's pretty good in principle - but you have to think about what happens to the grounds too...

Also, are you saying multiple 240vac lines, or 120vac lines?
One of the advantages of the 240-->120 stepdown is that it makes for a way stiffer line in general.

I'd be worried about voltage drops over multiple lines being different, and causing a ground problem on a 120v-->120v iso set up. With 240vac you have two hots and a dedicated ground there... dunno, I haven't thought this through all the way...
I'll have to get back to you later tonight. Running late today : ( Sean
Bear, the system that i was thinking of would make use of multiple high current isolation transformers all wired in parallel. These would be used for one 120 volt feed into a secondary breaker box. This box would be used strictly for A/V gear and would have a dedicated ground.

To achieve this, you would have a parallel feed coming from the mains of the houses' primary breaker box feeding the isolation transformers. In order to protect the transformers should a winding(s) short out, fuses would be installed on both the hot and neutral legs between the transformers and the mains. The parallel wired transformers would then feed the input of the A/V breaker box.

In effect, every circuit connected to this box would be filtered and isolated from the rest of the house and whatever noise was coming in via the outside lines. Not only would you have dedicated lines, those lines would all be filtered. One could then use smaller isolation transformers at the component feedpoint as needed. My primary thoughts are that one would want to use such an approach for digital gear. While this is not so much to further filter what is going into the digital components ( although it would do that), i was thinking more along the lines of keeping the hash and trash that such gear generates from being pumped back into the line and other components.

The total output of the parallel wired transformers would be rated for a higher level than what the secondary breaker box was rated for. This would insure that the transformers could not be damaged due to pulling on them too hard. If such a situation started to develop, the main breaker on the A/V box would trip long before the transformers could come close to saturation. At the same time, running more isolation transformers than needed would also guarantee a measurable amount of headroom so that core saturation would never take place. This would keep the power cleaner with less distortion than what other current limited filters might introduce.

Does this sound like a plan ? Any thoughts / suggestions ? Keep in mind that i've partially based this on the fact that i already have several "beefy" identical isolation transformers. I have not ruled out going to one "huge" transformer as that would surely be far simpler to install. At this point in time though, i've not run across anything that was reasonably priced although i have been looking. Sean

My comments were strictly regarding CODE requirements. The NEC only considers heat generation withing a cable when specifying its ampacity (current carrying ability). Many electrical engineers make their living sizing cable to carry power to voltage sensitive equipment.

I like your idea of isolation transformers on your system's dedicated lines. It would be easy for me to incorporate that addition to my system. One question, though: if cleaning up power is as easy as installing a transformer, then why are the PS Audio Power Plants so popular? It would be interesting to try a Power Plant in the same system using an isolation transformer and not using an isolation transformer. Then you'd know how much regenerating the AC sine wave contributes to the effect of the PP.
I'm not claiming that isolation transformers are better or equivalent to power regeneration. There is NO substitute for power regeneration. Regenerators start from scratch and provide the best that they can give you whereas isolation transformers are simply trying to separate the good from most of the bad. With isolation transformers, you can still end up with a high level of distortion if the sine wave is not "clean" to begin with. TRUE "power regeneration" corrects this problem but is EXTREMELY inefficient ( high levels of thermal losses / heat build-up ). This is not to say that i think that the PS is the best that one can do in terms of having "clean AC", but it is probably the most commonly used amongst audiophiles.

Having said all of that, i do think that isolation transformers have their place. So long as you never come close to saturating the transformer, i think that they are less detrimental to AC than most PLC's and many times, do a better job of getting rid of noise. There are a few "good" PLC's that simply make use of multiple smaller isolation transformers with additional circuitry supplementing the job that the transformer is already doing. Obviously, a smaller transformer is suitable for line level components and / or sources, but you would not want to run a power amp through one. Personally, i would not want to run a power amp through a smaller PS Power Plant either. If you had a very small amp or one that ran in Class B or was a "switcher" and had high efficiency speakers, i would not see a problem with doing so. Since most all of my speakers are low impedance and low efficiency and most of my amps are relatively inefficient high bias designs, that would not work for me.

If i had my "druther's", i'd "druther" have my own high current AC generator ( with a BIG muffler ) and a "kick ass" voltage regulator in the backyard OR be able to run off of a bank of batteries. Neither is practical for me though, although the generator might be more feasible depending on where i relocate to. I will probably leave an option in the wiring to either draw off of the AC line or be able to insert a generator into the path if / when i move.

Right now, i have enough transformer ( 170+ lbs worth ) to isolate at least 60 amps of current at 100% duty cycle and up to 80 amps for an extended period of time. I'm working on doubling that capacity. I'd like to have all of the "goodies" that i need to do this before i relocate. That way i can get everything wired in / laid out prior to moving in all of my "junk".

As i mentioned, this will feed a breaker box that will feed MULTIPLE systems, not just one. That is why i want such a high current capacity. While i will never have all of the systems "cranking" at one time or be able to pull that type of power at once, i am a firm believer in designing for "worst case scenario". My motto has always been "over-kill baby, over-kill". I'd rather "feast all the time" rather than "famine" just once : ) Sean