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15A vs. 20A power cord questions

I'm installing dedicated 20A lines with 10AWG cable and Furutech GTX-D 20A wall receptacles. I am currently using the standard IEC power cords that came with my Rogue Cronus Magnum and VPI Scout 1.1. 

I rather not upgrade the power cables at this time. I would like to see the effect the dedicated lines and outlets have first. Are there any issues with running 15A power cords into a 20A outlet and line? Would a 20A power cord possibly sound better or is it just a matter of the blade orientation?
asp307
jea48
4,313 posts
 

As for the current handling ability of a NEMA 5-15P 15 amp plug vs. a NEMA 5-20P 20 amp plug there isn’t any. If you look at the size of the hot and neutral blades they look exactly the same. Same length, same width, same thickness.

What is different between the 5-15P and the 5-20P plug is the orientation of the neutral blade. The neutral blade is turned 90 degrees of that of the Hot blade for the 5-20P, (20 amp), plug.

A 5-20P plug will not plug into a 15 amp receptacle. A 20 amp receptacle can only be installed, connected, to a 20 amp branch circuit. ( A 20 amp receptacle can not be installed, connected, to a 15 amp branch circuit.

A 15 duplex receptacle can be connected to a 20 amp branch circuit though.


And here is the stupid thing imo. A manufacture can build, and does, a power cord that has an IEC 20 amp female connector on one end and a 5-15P plug on the other end. And what’s worse yet, be UL listed.

Note: All per NEC code.

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cleeds
5,708 posts
 
jea48
 "As for the current handling ability of a NEMA 5-15P 15 amp plug vs. a NEMA 5-20P 20 amp plug there isn’t any. If you look at the size of the hot and neutral blades they look exactly the same ..."

Quite so. But the issue is not the safety of the connector itself. It simply isn't safe to use an adapter to plug a device that requires 20A of current into a 15A outlet.

" A manufacture can build, and does, a power cord that has an IEC 20 amp female connector on one end and a 5-15P plug on the other end. "

Quite so. And, if the device itself draws 15A of current or less, that's perfectly safe.

Some manufacturers use 20A connectors - even though the component draws less than 15A of current - because the 20A connector is likely to make a tighter fit with the receptacle. ARC has done this.
zephyr24069's avatar
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zephyr24069
1,241 posts
 
Absolutely true,..by the same token though, all manufacturers of power cords sold to audiophiles have one version of that power cord and then offer 15amp or 20amp plugs as an option. They don't wire the cord any differently for 15 versus 20 amp applications; they all seem to 'overbuild' a bit for 20amp as a likely outcome.  As pointed out above, there is no difference in the connectors themselves in terms of current handling; my comments above were assuming that people know not to plug a 20amp component into a 15-amp circuit if that component truly draws well above 15 amps 'steady state'; that is how fires start, not due to the connector itself from what a couple of electricians have told me. All that assuming of course that the breaker in the box is faulty and does not trip in the first place...

If I've got any of this wrong, please let me know. I'm working off what a couple of electricians and high-end cable experts have mentioned over the years.
jea48
4,313 posts
 

jea48 said:
" A manufacture can build, and does, a power cord that has an IEC 20 amp female connector on one end and a 5-15P plug on the other end. "

cleeds
Quite so. And, if the device itself draws 15A of current or less, that’s perfectly safe.

No, the equipment shall not draw more than 12 amps FLA continuous load per NEMA, NEC, and UL for a cord and plug where the manufacture wants to use a NEMA 5-15 (15 amp) male plug.

16 amps max for a 20 amp cord and plug if the equipment manufacture wants to use a NEMA 5-20P male plug.

Works great when the equipment comes with a captive held attached power cord.


How about the guy that goes out and buys a big honken Krell amp that has a 20 amp male IEC connector on the back of the unit, a power cord made of #10 wire, conductors, with a 20 amp IEC connector and a NEMA 5-15 (15 amp) male plug on the other end. The user plugs the NEMA 5-15P plug in convenience outlet 15 amp duplex receptacle in the living room, no problem at all. Perfect fit.

The user turns on the amp and trips the breaker in the electrical panel. The user calls the dealer and says, hey there is something wrong with the amp. Every time I try to turn on the amp it trips the breaker at the panel. I tried it at least a half a dozen times. Dealer response: The breaker is probably a 15 amp, just change it out to 20 amp breaker.


Next time you go to a hardware store or Home Depot see if you can find an extension cord with a 5-20R (20 amp) female cord cap on one end and a 5-15P (15 amp) plug on the other end. You won’t find one......


asp307 OP
159 posts
 
@mofimadness @zephyr24069 @jea48 @cleeds 

thanks all, this is now clear to me. Regarding a twisted pair or standard cable to link the breaker to the outlet, any advantages or is it all about the grounding?
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