If the plug on the power cord is a NEMA 5-20P 125V 20 amp rated plug then per NEMA, UL, and NEC code the amplifier continuous FLA (Full Load amps) cannot exceed 16 amps. 20 amps X 80% = 16 amps. Continuous is 3 hours or more. Per NEC electrical safety code the required branch circuit size is 20 amp. Also because of the FLA, imo, the 20 amp branch circuit should be a dedicated circuit strictly to power the amp. If it were me I would have #10awg wired installed. The breaker at the electrical panel has to be 20 amp. Receptacle, 20 amp. IF the amp does not have a soft start circuit for start up and causes the circuit breaker to trip once and awhile due to high inrush current you may need to have a 20 amp HM (High Magnetic) breaker installed. A HM breaker has a longer lag time for inrush current. DO NOT install a 30 amp breaker. Example of a 20 amp HM breaker: Standard QO115 and QO120 circuit breakers are manufactured to have a magnetic trip point at approximately 8x to 10x the breaker rating. There are some applications, however, in which a load has an inrush current high enough to cause these standard circuit breakers to trip. Examples of these loads include area lighting for athletic fields, parking lots, or outdoor signs. To allow the high inrush current without tripping the circuit breaker, a high magnetic breaker should be used. These high magnetic breakers have a magnetic trip point set much higher than the standard circuit breakers. They can be identified by the HM suffix on the catalog number (QO115HM). Current production HM breakers are also identified with a "High Magnetic" label on the side of the breaker (see photo).http://www.schneider-electric.us/en/faqs/FA96714/ |
Your dealer told you wrong information. That amp does not use near 2400 watts. Here is the info showing 800 watts total . A 15 amp circuit is sufficient! https://www.cambridgeaudio.com/products/851/851a |
Loads of amps (for example many Audio Research amps like my Ref 40 and Phono 2SE or my VTL MB 450s) use 20A female IECs like this. They do not need a special outlet. Also they use standard male plugs just like all the other items in your hifi, youll just need a 20A IEC power cord. The 2400W rating is a peak value that is likely to be reached rarely if ever and likely only for an instant. Clearly don't try to plug this in to an extension cord (and as others have noted make sure your wiring is up to spec) but other than that you should have no issues. |
Ps @yogiboy is wrong he gave the specs for the 851A, which clearly Has a 15A IEC. The 851W amp is specified at 2400w peak see the tech specs here https://www.cambridgeaudio.com/products/851/851w |
Hodu, At 200 watts per channel amp if you will be pushing the amp with high dynamic music don't let the electrician talk you into using #12awg wire. #12 is bare minimum for a 20 amp circuit. Stick to your guns and tell him #10 wire. You want the mains voltage to hold constant and not fluctuate when the power supply is trying to recharge the Caps. IF you can have him install 10-2 with ground NM-B cable. (Romex is a Trade Name of). Whether or not he can use NM-B will depend on the local electrical code as well as whether the wiring installation of NM-B will meet local code. If he cannot use NM-B ask him if he can use 10-2 with ground solid conductor MC aluminum armor cable. NOT stranded wire. |
You can use ohm's law. Here is a calculator that shows you will need a 20 amp circuit for peak power with this amp. http://www.ohmslawcalculator.com/ohms-law-calculator |
Je48 sounds like he knows his stuff! I'd listen to him! But I will add that I just got a Krell FPB-300, with a 20amp plug, and it came with a cord that has the 20amp connector for the amp on one end, and the other end has a standard 15 amp plug on it. I plugged it into my APC power filter, which has a gauge on the front to tell how much current is being used, and so far I've never seen it move, or even get to the yellow, never red. So in practice you can get away with a 15 amp circuit. But, after reading what je48 said, I'm also considering a dedicated circuit for it! Certainly a good piece of mind. And isolate it from the rest of your gear. |
Can I use this amp in my house? Cambridge Audio 851W Safe with normal power points and normal 10amp cords That will be maximum "peaks" just on clipping, half that and half it again, for something closer to the real thing even that's stretching it.. Cheers George |
But I will add that I just got a Krell FPB-300, with a 20amp plug, and it came with a cord that has the 20amp connector for the amp on one end, and the other end has a standard 15 amp plug on it.Crazy ain’t it? And it might even be a Listed power cord assembly. Maybe even by UL. A power cord with a 20 amp female receptacle on one end and a 15 amp male plug on the other end. Oh, the plug will easily handle 20 amps. But what about the 15 amp in wall branch circuit wiring it might be plugged into? But what If? On the back panel of the Krell amp, usually by the IEC power inlet, what is the FLA, or power consumption (in watts or VA)? If the Krell is a Listed piece of equipment it should say, somewhere on the back panel. If the FLA is 12 amps or less the IEC inlet can be 15 amp. (15 amp X 80% =12 amps). If over 15 amps but not more than 16 amps then it has to be a 20 amp. (20 amps X 80% = 16 amps). Just curious, what is the size, wire gauge, of the conductors/wire in the power cord? 16 gauge? 14 gauge? If it is a Listed power cord it should say on the cord. 16 gauge is plenty big for a 15 amp Listed power cord. What do you think though? Do you think 16 gauge might have any impact on the SQ of the amp when you crank up the music level? Try to buy a short power cord with a standard NEMA 5-20R 20 amp female connector on one end and a NEMA 5-15P 15 amp plug on the other end that is Listed by any recognized third party testing laboratory. You won’t find one. Why do you suppose that is? . |
@jea48 So I live in a rental home and aren't free to add dedicated lines. etc. I am considering buying a stereo amp or a pair of monoblocks that like @alpha_gt described have 20A female IEC and comes with PC with 15A male prongs. The house is has 1950s-50s era wiring with fuses not circuit brakers if that matters. Should @alpha_gt's experience give me comfort that similar will not cause a problem here, or do I need to go for the smaller amp option with the standard 15A IEC? Cheers, Spencer |
sbank, What size of amp/s are you looking at? I should have mentioned in my last post, just because the manufacture installs a 20 amp IEC inlet on the back of his equipment doesn't mean he had to do it to meet bare minimum electrical industry standards. He may of used the 20 amp IEC inlet because he thought it made a better male to female connection than the 15 amp IEC connectors/connection. When it comes to IEC connectors I don't think there is anything that says he can't. Unlike Nema electrical standards from my experience. Just a guess Krell had to on a 300 watt per channel power amp. I believe Krell uses a pretty hefty over built power supply in their amps. If the amp is driven hard will it continuously draw over 12 amps of power without blowing its' AC line fuse, or circuit breaker if that is what it uses? If so then Krell had to use the the 20 amp IEC inlet connector. That is, imo, if it is Listed. . |
Audio Advisor says: "In fact, the 851W is so powerful that a normal AC power cable can’t deliver the current required. We supply the 851W with its own dedicated, high performance 20 amp AC power cable."What a load of r****sh This is it at clipping tested by Newport Labs. 8Ω loads, the 851W was able to deliver 223-watts 4Ω loads, it delivered 351-watts per channel 2Ω loads, and able to deliver 509-watts The clipping indicators came on right at the onset of clipping Cambridge pulling more than 200-watts from your mains power supply during normal operation, and nearly 700-watts when you’re listening at high volume levels. Cheers George |
sbank, From the manual, Full Power Balanced Power Amplifiers600, 300, 200 Stereo650M, 350M, 250M Monaural AC Power Considerations See page 12 Trouble shooting.http://krellonline.com/assets/support/FPB_ORIGINAL_SERIES_MANUAL_V982.pdf So The way I understand it as long as you do not push the amp hard a dedicated 15 amp circuit is fine. Note dedicated 15 amp circuit. If a 15 amp convenience outlet branch circuit were used the amp may not preform to specs. It might/would depend on what other loads were sharing the branch at the time you were listening to the amp. One other caution. If it is plugged into a 15 amp convenience outlet branch circuit the circuit breaker at the electrical panel may nuisance trip occasionally when the amp is first turned on from a cold start up. The standard breaker may not be able to pass the high in-rush current draw from the amp’s power transformer and charging the electrolytic caps in the power supply. If you bought the amp and it trips the breaker, the more times the breaker trips, the more often it will trip, as it gets weaker. That’s the good news. The bad news is possibly at some point the breaker may malfunction and will no longer trip. At that point it is nothing more than an on off switch. The #14awg branch circuit wiring will no longer be protected. There is an old thread on Agon, somewhere, I was involved in. Guys posted the breaker in the electrical panel was nuisance tripping. They were told to just change it out to a 30 amp breaker. Big mistake! Jim . |
You are looking at specs for the foreign model that uses a 240v line. This amp uses way less wattage than a microwave. I run this amp on the same circuit thru my Panamax as my tv, DVD player, wifi, DIRECTV, 851n, 851e, and this amp in a large open room with 12ft plus ceilings. The Panamax has never indicated that I had any voltage draw issues |
