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Got big amp-help with 20A line and receptacle

So, I just purchased a Krell FPB 400cx, which I'm told requires a dedicated 20 amp line. Yes, I have read some Agon threads on running dedicated lines, as well as 20 amp receptacles. But they are mostly several years old and I am interested in some current basic recommendations.

I am not looking for the most expensive or esoteric setup, but do want to do it as best I can. The receptacle location is in the family room, which I estimate will require about 50-60 feet of cable from the breaker box in the garage.

So, at first all I knew was that I would be running a new line from the breaker box and that it would be grounded there. But some posters here and elsewhere stated that I should have an isolated ground installed outside the house and at least 6 feet from the existing ground. There were also suggestions around exactly which location IN the breaker box to place the new line and breaker.

We do have three refrigerators here, one in the kitchen, one in the utility room, and another in the garage. Of course, we we have all the other typical appliances in the house. One good thing is that, in my current setup with no dedicated lines, I don't hear any noise through the speakers unless I use the dimmer in the family room. So, maybe the power in the house is pretty decent.

With regard to receptacles, I've read various comments about the different brands, as well as the various effects of gold, rhodium, or other plating. To start with, I would like to try the most neutral sound I can get.

I did speak with two electricians today, and neither seemed to have much familiarity with the considerations for audio quality that I mentioned to them. Therefore, I would like some input on what to ask of them. If I am making this too complicated and harder than it needs to be, I'd like to know that as well. I would really appreciate any tips and input!
mtrot
jea48
2,944 posts
 

they want me to use a 30 amp single pole breaker so that my amp will run smoother, less heat, draw more current on demand, my sound stage will sound bigger and taller, and everything else, remember, all this is what krell swears too, they run my amp and the 750mcx amps on a 30 amp breaker thier at the factory, also,
11-11-14: Audiolabyrinth

Audiolabyrinth'

"They" told you wrong. First off the current carrying guts inside of a 20 amp breaker are the same as a 30 amp breaker. Only the trip unit settings are different. A 20 amp breaker will pass short bursts of current of over 100 amps all day long.

Per NEC Code a 20 amp NEMA 5-20R receptacle can only be connected to a 20 amp breaker. Minimum size branch circuit wire, #12 awg. The breaker size determines the size of the branch circuit. If # 10 wire is used the breaker still has to be a 20 amp if the receptacle is a NEMA 5-20R receptacle.

IF by chance the breaker is tripping occasionally on start up from high inrush current most breaker manufactures make a breaker with a longer lag time for high inrush current.
Example
>http://www.cesco.com/b2c/product/33471?gdftrk=gdfV25445_a_7c1847_a_7c7081_a_7c33471&gclid=CIurm-rygMICFY6EaQodj0MAvg

Two or more 15 amp NEMA 5-15R receptacles can also be installed on a 20 amp branch circuit. Per Code a 20 amp receptacle cannot be installed on a 15 amp branch circuit.
audiolabyrinth's avatar
audiolabyrinth
4,483 posts
 
Thankyou Jea48, You are correct, however, useing the 30 amp breaker on my 10 awg 3/1 romex cable will allow for more current with a furutech GTX-D recepticle, although the recepticle is 20 amps, it is overly built and will with stand a 30 amp load!,my amp will never continously play at these amps, we both know that, but krell said that my amp will spike over the 20 amps quite often, thus useing the 30 amp breaker will allow me to get more current, I can tell you for fact from exsperience that when I owned a Krell FPB 200 amp years ago, I pluged it into the house wireing recepticle, talking about a laughing matter, the amp litterally blew light bulbs and dimmed the others in a apartment I use to live at, when I installed the correct circuit, and back then I had a dedicated ground, all was well and sounded alot better, thanks for the info you posted, I enjoy learning all I can from you and others,BTW, My current 20 amp set-up does trip from time to time, mostly when I am breaking in some audio equipment or cables,that is very strange,, Jea48, also I have talked to many FPB 600 owners here on audiogon over the past couple of years that did the 30 amp breaker, their findings were the same as krell specified to me about the out come of doing so, cheers.
jea48
2,944 posts
 
Audiolabyrinth,

Were you told by a Tech at Krell over the phone or through an email? Just guessing it was over the phone. See if the guy will send you an Email stating "Krell" recommends you use a 30 breaker to feed a 20 amp rated receptacle. Tell him you want to post it here on Agon.

As I said in my previous post the current carrying guts of a 20 amp breaker are the same as a 30 amp breaker, exactly the same.In fact they are the same as 40 amp breaker. Only the thermal and magnetic trip settings are different. And of course the number printed on the breaker handle.

As for the FLA rating of the Amp IF the amp is UL/CSA Listed the most continuous power the amp can draw is 16 amps, 80% of 20 amps. If it is over 16 amps the manufacture would then have to use a 30 plug mated to a 30 amp receptacle connected to a 30 amp branch circuit to get the UL/CSA Listing.
audiolabyrinth's avatar
audiolabyrinth
4,483 posts
 
Jea, My amp can be accomidated to run 220!, it's their at the krell factory now!, I do not understand what you are saying, your facts are based in general, not my particular amp!, I know my amp very well, and I know what I am doing, I did all my electrical here, works with no issues at all, I will give my impressions when I am done with what I will do, read and learn what is possible from a Krell 700cx or 750mcx amplifier, I am sorry to come across so direct, when having the factory and many users tell me what i am doing is correct, it feels right for me to do what is said, cheers.
csmgolf
479 posts
 
To the op and others considering doing this, please follow the advice of Jea48 and make sure that you follow electrical code in your area. Re read all of his posts and read the links. Great info. You seem to be doing the correct investigating before beginning.
It would be wise to be very leery of the advice from a person telling you to do it this way because I said so and it is how I did it. Heck, he still has breakers tripping and is not sure why. Think Tim "the tool man" Taylor from the show Home Improvement. More power! Woof, woof, woof. You know how that normally turned out for him.
Good luck with your project.
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