[mclsound]

Well I just got a Krell FPB700cx in the room and was testing her limits on Madonna's Vogue,and shut down the breaker....so now I am going to run some 10awg wire and a 30amp breaker with,I guess,a good 20amp receptacle??
Any suggestions without the $100-$200 price tag.
I currently use levitron 20amp hospital grade decore(red) that I got from a local electrical shop here in Ontario for around $15 each.
thanks john

[srb]

If you are wiring a single receptacle to a 30A breaker with 10ga wire, then the receptacle needs to be rated at 30A, which requires a special plug.
 

 
Most electrical codes require a receptacle that matches the breaker rating if there is only a single outlet on the circuit, but they also may allow a receptacle rating that is less than the breaker rating if multiple outlets are installed on the circuit.
 
However, in your case, if you are actually drawing more than 20A for your device, then having a receptacle rated at only 20A on a 30A circuit puts you at risk of overloading the receptacle's capacity and could result in overheating, meltdown or even fire.
 
There might however, be other factors involved.
 
1.  The circuit run is sufficiently long that there is too much voltage drop and a 10ga wire might be needed on the 20A circuit
 
2.  The breaker is weak and is tripping prematurely and should be replaced.
 
Since Krell recommends a 20A circuit for that amplifier, I would think that one or both of the above conditions might possibly exist.
 
Steve

[Speedskater]

"srb" I agree that the code rules may regulate what receptacles may be used.
But it would be hard (very hard) to overload a receptacle with audio equipment. Wire has a nearly 100 % overload safety factor and I believe that a receptacle's safety factor is much greater than wire. In any case the amperage rating is based on 3 hours of continuous current.

[srb]

The fact remains that Krell's recommendation is a 20A dedicated line to run this amplifier.  So either
 
a.  Additional components are also being run off of the same circuit
 
b.  The breaker is tripping prematurely and should be replaced
 
c.  This is the Music God's response for even owning or playing "Madonna's Vogue"
 
Still, I wouldn't personally put a 20A receptacle on a 30A circuit to run this amplifier for a variety of code, safety and insurance reasons.
 
Steve
 
 

[Don_S]

I agree with Steve's comment on the breaker condition:

"2.  The breaker is weak and is tripping prematurely and should be replaced."

I had this problem with an amp that did not have a soft-start.  Sometimes the breaker would trip (dedicated 20 amp circuit) when I turned the amp on. I had a similar situation running my vacuum cleaner off of a different circuit that served the bedroom.  In both cases I replaced the breaker and the problem was solved.
There is no need to get exotic or complicated.  Try the simple/inexpensive solution first. Good luck.

[Speedskater]

"srb" save for the one small detail about "overloading the receptacle's capacity" I agree with everything that you have written.

[mclsound]

Steve,play nice.I only use her for testing the bottom end and she flipped the breaker.I use four dedicated 20a lines and will install a 30a this wknd.Prbably not weak as I was testing the waters and it probably did overload the circuit(my hair was moving).I have no probs putting in a 30a receptacle but need to see about the Krell cable.
thanks guys
john

[Speedskater]

NEC Table 210.21(B)(3) limits receptacle's on a 30 Amp circuit to only 30 Amp receptacle's.
The NEC rules prohibit cutting a 15 Amp or 20 Amp plug off of a line cord and replacing it with a 30 Amp plug.

[srb]

Steve,play nice.

John, I was about to say WTF?, then I realized ..... it was the crack about Madonna.
 
It is somewhat rare to trip breakers on a dedicated amplifier line rather than the amplifier's fuses, but that is a beast of an amplifier if there ever was one.  You did at least get some thoughts for consideration on the 30A circuit, although you haven't yet gotten any 20A receptacle recommendations that you asked for.
 
You certainly are well supplied with 4 - 20A dedicated lines.  Good luck.
 
Steve

[Wayner]

This discussion has gone slightly to the out of bounds area. In the OP,  the statement was made that the single amplifier was connected to the  single 20 amp circuit and popped the breaker, if I understood that part.  A couple of comments can be made right here. Either you are driven to  destroy your amps or your speakers or both, (or hearing) and "testing  the limits of a system is pointless and futile. Would you then see how  absolutely fast your new car could go?
 
 Next, I doubt if your Krell amp came with a 20 amp plug on it, or am I  incorrect on this statement? If not, the high inrush current of your  amplifier is making the circuit breaker do it's job. I doubt there is  anything wrong with the breaker as the problem is at the other end.  Installing a 30 amp outlet is also pointless, and for what, to see how  "fast" your car, I mean your system can play? Again, this is pointless.
 
 Wayner

[mclsound]

Well there Wayner,when a amp comes with 10/3 for a power cable,well need i say more...destroy amps-this is one thing I do not do...these audiophile expensive amps are built for this and should be for a list of $14,000...as for speakers,well I used studio 40's for rears,V2's I believe,liked them better than V3's...Drums and bands for 20 some years does take a toll,for sure!!! All this is fine BUT Wayner you steped over the boundry with the """FUTILE""" statement.Audio is all about  limits
-Best possible CD,CD player,amp,speaker,speaker capability,all analog possibilities..ETC.
I will kindly ask "if you are here for POINTLESS comments,move on to the 50db site my friend.
I love my music differently than you and your MF club.As far as cars,well if I had a 1969 Dodge Roadrunner with a 440 six pack,I would see what she does as much as possible.

Steve-I had the opportunity to redo my room and have installed 8-20amp(4/front...4/rear...incase I move my room around)...I am installing a 30amp this wknd...and Yes it was the comment(LOL) on her,but that song does test waters.

[ctviggen]

I don't know if it's possible to cause a breaker to trip while merely playing music.  Especially if the amp is on its own 20 amp circuit.  And 10/3 doesn't make sense, unless the amp is 240V. 

[Wayner]

Well there Wayner,when a amp comes with 10/3 for a power cable,well need i say more...destroy amps-this is one thing I do not do...these audiophile expensive amps are built for this and should be for a list of $14,000...as for speakers,well I used studio 40's for rears,V2's I believe,liked them better than V3's...Drums and bands for 20 some years does take a toll,for sure!!! All this is fine BUT Wayner you steped over the boundry with the """FUTILE""" statement.Audio is all about  limits
-Best possible CD,CD player,amp,speaker,speaker capability,all analog possibilities..ETC.
I will kindly ask "if you are here for POINTLESS comments,move on to the 50db site my friend.
I love my music differently than you and your MF club.As far as cars,well if I had a 1969 Dodge Roadrunner with a 440 six pack,I would see what she does as much as possible.

Steve-I had the opportunity to redo my room and have installed 8-20amp(4/front...4/rear...incase I move my room around)...I am installing a 30amp this wknd...and Yes it was the comment(LOL) on her,but that song does test waters.

The 10/3 cable makes no difference. It's the plug that comes with it does and I'll bet it was the standard 15 amp. I don't care if your amp cost $14000 or 140. Your points are ridiculous.

Me

[mclsound]

obviously the end will need changed..It is not the cost of the amp anyways,its the power...a Bryston 14bsst has a 2kv transformer,Classe CA-400/2.8kv,Simaudio Titan dual 1.1kv,Krell 700 2-4kv...POWER WAYNER...she's the 440 six pack buddy

CT-Maybe 10/2,I work away from home so it's not in front of me but i'll check.

[srb]

CT-Maybe 10/2,I work away from home so it's not in front of me but i'll check.

I was looking at photos of the FPB700cx on the Krell site and could clearly see "10/3" on the Carol captive cord.  The designation of 10/3 on that type of cord means it has three conductors (and one is being used as the ground wire), as opposed to a Romex-type NM cable's designation of "10/2 with ground".
 
Steve

[linyanti]

This is such an interesting topic. "Voltage Drop" is a problem for lots of equipment besides audio. Having excess capacity on the line helps to keep this from being a problem.

But this Krell FPB700cx is insane!

From the manufacturers website this device has a maximum draw of 6,000 watts! It idles at 430 watts.

A 120 volt 15 amp circuit will provide 1800 watts steady and a 20 amp circuit will provide 2400 watts.

To have UL certification the plug on the device should be appropriate for the current. The manual states that the FPB700cx should have a dedicated (no other device on it) 20 amp circuit. I cannot tell from the manual whether it comes with a 15 or 20 amp plug.

I think that there are two options. The first would be to do what the manufacturer requests and that is to have it installed on a 20 amp dedicated circuit. If that is not sufficient then the manufacturer should be notified.

Another option which is kind of off the wall is to do something that was the rage in the early 1990's and that is to get it rewired as a 220/240 device. This is pretty easy since they already do it for the products they sell in Europe. Then a 10 gauge wire is capable of carrying twice as much current and the "voltage drop" should be less. Then have the correct plug, outlet and breaker to meet the electrical codes. A ten gauge wire can handle 40 amps easily.

I would be very interested in what a watt meter would read. I have a Watts Up device and it will show amps, volts, etc for instant, max and min. It would be enlightening to see the maximum amps needed to run the amplifier and also how low the voltage goes when the amplifier is maxed out.

It would also make sense to get some capicatance upstream from the device but the manufacturer specifically states that you should call them before you put anything in between the amplifier and the electrical outlet.

[mclsound]

steve-she is a 10/3 and must admit that it was like a anaconda when I was pulling her out of the box....well ""WE"" were pulling her 180lbs out.

L-"""INSANE""" is a lovely word in the world of audio.I figured that 1800/2400w was a little low for a pair of 4kv transformers.My speakers are a solid 4ohm but they have never been measured for dips.I am going to go 4-way(this winters project)and should add a little more to the kettle.It is a 15/20 plug on 10/3 and 220volt came to mind but I will see which route i will go.
I must admit,when the breaker blew,she was crystal clear without a lick of distortion...but ""Vogue""(sorry steve)tends to warm a room up.

[linyanti]

mclsound, there is one other issue regarding the electrical circuits in your house.

When the electrician calculates the size of the breaker panel (either the main panel or the sub) there is a standard calculation but it is not obvious.

For example, my a/v room comes off of a 125 amp sub panel. But there are about thirty 20 amp breakers on the panel. That would equal 600 amps if all the circuits were being maxed out. The calculation assumes that most of the circuits will have almost no current draw.

But since the circuit breaker panel in your situation is seeing lots of current from multiple breakers then you may be overtaxing your panel and the calculation may not be valid.

How many amps is the panel? If it is a sub panel then you may have to pull bigger wire from the main panel. Or if it is the main panel then you may be able to increase the amps of the panel without digging a new line to the house.

Regardless, this is a problem that Krell probably encounters frequently. They may have a white paper on how to increase your current.

[mclsound]

So I was in contact with Krell today and Ray and Walt say 30amp breaker,10awg wire,and a 20amp receptacle is what we want.

Hi L
I do use a 100amp sub panel but there was nothing on that night but ""VOGUE""(LOL).I use a 100amp romex(6awg???).
Now to look for a good receptacle.

[linyanti]

That sounds like a good solution if done correctly. It is proper to use a receptacle (the 20 amp duplex outlet) with a breaker larger (the 30 amp breaker) than what the outlet allows. But if it routinely trips a 20 amp breaker then maybe the amp should not come from the manufacturer with the plug it has.

However, if you are upsizing your electrical system breaker capacity then you may want to have a licensed electrician do the work rather than just going to a hardware store and buying a replacement breaker.

That is because the length of the wire (you already have 10 gauge wire) is important as is the size of the breaker box. If there are unused breaker switches in your breaker box now then you probably have enough capacity in your breaker box but the electrician knows how to calculate the total amperage load for the circuit and also the box.

I still am very curious about the current draw. If you get a Watts Up or similar current measuring device then it would be interesting to see how high the load goes and if the voltage drops. At the load of current the Krell is drawing you may see the streetlights dim during loud musical passages!