15A vs. 20A power cord questions

A 20-amp power cord must have 20-amp rated connectors on both sides along with #12 or larger conductors.

I would agree, for a 20 power cord.

If you have a cord that has #12 or larger conductors (or multiple conductors totaling over 12awg in area) but 15-amp connectors on either or both sides, it is still a 15-amp cord. Manufacturers usually call that a "high current" or "amplifier" cord but they cannot call it a 20-amp cord.

Again, I would agree with your above statement.

If your equipment -- like most equipment -- has a 15-amp connector (C-14 receptacle) then you cannot use a listed 20-amp cord because it will not fit.

And again I agree.

But what if the manufacture of a CDP installed a 20 amp IEC male connector on the back because he believes the 20 amp IEC connectors connection is better than a 15 amp IEC connectors and the FLA on the piece of equipment is, say, 2 amps.

If he supplies the power cord for the amp The IEC female connector will naturally be 20 amp and I can guarantee the male plug will be a NEMA 5-15P (15 amp) plug. The conductors of the cord who knows. Could be #14, it could be #16 gauge.

Because it has a 15 amp male plug, and the conductors are 16 gauge can you truly call that a 15 amp power cord?

See that’s the problem with IEC connectors. There isn’t any real standardization. They are not idiot proof.

What happens if the user someday finds it in his odds and ends box and uses it on a big Krell power amp, (he just bought used that didn’t come with a power cord), that has a 20 amp IEC connector on the back of it. Must be ok to use. It plugged in the back of the amp and the plug plugged into the wall 15 amp duplex receptacle. If the cord is 6ft long and the wire is 16 gauge because of the VD + heat that will be generated by the connected load to the hot and neutral conductors add that to a possibly long length of the in wall #14awg branch circuit wiring there is a chance the current passing through the 15 amp circuit breaker may be less than 15 amps. In that case the breaker could very well not trip open.

The power cord will not affect the power consumption or current draw of the amplifier. Your amplifier’s fuse will limit the current well below the 80% listed amp threshold for the power cord.

Well not in the sense power consumption meaning it can deliver more power than the branch circuit can deliver but it is possible depending on the wire size used in the cord and the connected load VD, voltage drop, could be a factor, there in limiting power to an amplifier. Even if the fuse is a slow blow 8 amp fuse it will easily pass short spurts of current draw well exceeding the fuse’s 8 amp rating if the power amp is being driven hard playing high dynamic music.

Best regards,

Jim

I am an easily confused old man.

My Atma-Sphere MA-1 140 watt tube amps use 5 amp fuses.

When I look at these fuses, the wire connecting one end to the other is absolutely tiny. At my age I need reading glasses to see it. Yes it is that thin.

This is the conduit through which the electricity flows. All the electricity.

The question I have: do you have an isolated ground with this dedicated 20amp service?.

This involves running a new wire outside, connected to a new copper rod, and having that rod driven into the ground, deep.

I am an easily confused old man.

My Atma-Sphere MA-1 140 watt tube amps use 5 amp fuses.

When I look at these fuses, the wire connecting one end to the other is absolutely tiny. At my age I need reading glasses to see it. Yes it is that thin.

This is the conduit through which the electricity flows. All the electricity.

The question I have: do you have an isolated ground with this dedicated 20amp service?.

This involves running a new wire outside, connected to a new copper rod, and having that rod driven into the ground, deep.

LOL, there is a lot more to many aftermarket power cords than merely the size of the conductors used. Nothing posted thus far has addressed any of that.

>>>>>>>>>>>>

Here is a quote from a post from Ralph, of Atma-Sphere:

"With power cords its all about voltage drop across the cord. Some of that is at 60Hz, and some of that is much much higher- well above 30KHz-100KHz depending on the power supply in the unit with which it is being used.

I’ve seen a 2 1/2 volt drop rob an amplifier of about 30% of its output power. The cord was rated for 10 amps, and the draw was about 6 amps. This measurement was done with a simple 3 1/2 digit Digital Voltmeter.

The more insidious problem is high frequency bandwidth. The power supplies of most amplifiers have a power transformer, a set of rectifiers, and a set of filter capacitors. The rectifiers only conduct when the power transformer output is higher than that of the filter caps. So:

When the caps are fully charged the amp is able to play. As it does so, the caps are discharged until the AC line voltage waveform gets high enough again that the rectifiers in the power supply are able to conduct. Depending on the state of charge of the filter capacitors, this might only be for a few microseconds or it might be a few milliseconds. Either way, the charge is a spike which has very steep sides- and requires some bandwidth to make it happen.

If the power cord has poor high frequency response, it will current limit on these spikes. This can result is subtle modulations in the power supply or even a sagging power supply voltage.

Romex wiring found in many buildings actually works quite well. So it really becomes all about that last few feet and also how well the power cord is terminated- molded cords generally are not terminated very well. If the ends of your power cord get warm after a while, you know you have a problem!

This can be measured, its quantifiable and also audible as many audiophiles know. Anyone who tells you differently probably has not bothered to do any measurements- please refer them to this post.

I can go into more depth but this is it in a nutshell. Incidentally, Shunyata Research is refining an instrument that does a more in-depth analysis of what this is all about. At the link you will see that their tests essentially confirm what I have said here."
http://www.theaudiobeat.com/visits/shunyata_visit_interview.htm

End of quoted material.

>>>>>>>>>>>>>>>>>>>>>>>>>>>

Agon thread Link:
https://forum.audiogon.com/discussions/audiphile-power-cords#41

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As for the use of an isolated earth ground rod, that’s a no, no.

The purpose of the safety equipment ground is to provide a low resistive path for ground fault current to return to the source. Mother earth is not a low resistive path. If the earth is used as a path for ground fault current, and there is a ground fault event, the area around the earth driven ground rod works great for hunting fish worms.

The earth does not possess some magical mystical power that sucks nasties from an audio system.

Hi gs5556,

Glad to see you posting again.

Most manufactures of audio equipment want and need to use a 15 amp plug to feed their equipment. As you know the majority of the convenience outlet branch circuits in homes are 15 amp, using #14awg copper wire. Only a 15 amp receptacle can be installed, connected, to a 15 amp branch circuit.

Audio Manufactures wouldn’t sell much equipment if they used a 20 amp male plug. So they need the 15 amp plug if they are going to sell audio equipment to home consumers in the US and Canada.

I think the problem with some manufactures, that build big amps, isn’t that their equipment draws more than 12 continuous amps. That’s a lot of amps for an amplifier in a home. 12 amps X 120Vac = 1440 VA, watts.

The problem is some manufactures are too tight to install a soft start circuit for powering up the amp. Without a soft start circuit the full inrush current trips the 15 amp branch circuit breaker at the electrical panel. And the bad thing, the manufacture probably knows it’s going to happen.

Sometimes in the owner manual it might say the amp should be fed from a 20 amp dedicated circuit. And that is the manufacture’s way out. In some cases even a standard 20 amp breaker will trip due to inrush current.

Jim