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# 250v amperage rating vs. 125v

#1
12-30-20, 09:40 AM
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250v amperage rating vs. 125v

Hello all,

I build small custom amplifiers and one of the parts I use is an IEC AC receptacle. The rating for the receptacle is 10A @ 250VAC. However, all of my amps are used exclusively in the US, so voltage is 125VAC max.

If an IEC receptacle is rated for 10A @ 250VAC, does this mean it is also only safe for 10A @ 125VAC? Or does the max amperage it can handle increase as voltage decreases?

I ask because I assume the product rating is based on temperature, so at 10A/250VAC wattage would be ~2500w whereas the same wattage at 125VAC would draw 20amps....and wattage is what plays the main role in temperature?

Thanks for clarification!

#2
12-30-20, 10:14 AM
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If a receptacle is rated at 10 amps 250 volts it is good fro 10 at 125 volts.
However by code you cannot use a 250 volt receptacle for 125 volts. You must change it a 125 volt rated receptacle. The pin configurations are different so that you cannot plug a 125 volt rated device into a 250 volt receptacle.
Also if you half the voltage the amp will double with the same load. So a device rated 10 amps at 250 volts would need 20 amps at 125 volts.

#3
12-30-20, 10:59 AM
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Originally Posted by dlaunde
f an IEC receptacle is rated for 10A @ 250VAC, does this mean it is also only safe for 10A @ 125VAC? Or does the max amperage it can handle increase as voltage decreases?
Oversimplifying, US current uses four wires, #1 is +120v #2 is -120v, #3 is the neutral that is meant to return current, and #4 is ground/earth which is a safety valve.
You can visualize this as a high school bathroom, you have a sink with hot water, cold water, and a drain, but there is ALSO a floor drain for emergencies if the sink drain doesn't work.

Generally, the IEC standards set maximums, and the cords that go into those receptacles are rated to 240V @ 10A, the rating at lower voltage depends on the gauge of the wires used.
Generally, they're interchangeable, as you'll see that older computer power supplies have a 120v / 240v slide switch, OR are listed as AUTOMATIC because they sense the chagne.

#4
12-30-20, 11:20 AM
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The IEC equipment connector was designed as a universal connection for electrical/electronic equipment under 250v. There is no 120v or 250v device. The device is 250v maximum.

#5
12-30-20, 12:21 PM
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Yes. An equipment receptacle, plays by different rules than a premise receptacle, as far as voltage rating. I’m not even sure if the machine male connector is even called a receptacle.

#6
12-30-20, 12:26 PM
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Originally Posted by PJmax
The IEC equipment connector was designed as a universal connection for electrical/electronic equipment under 250v. There is no 120v or 250v device. The device is 250v maximum.
Agreed. But the cheap knockoff cords are so thin that I wouldn't trust them with a sustained 20 amp / 125v load.

#7
12-30-20, 01:39 PM
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A 10 amp rated receptacle is 10 amps no matter what the voltage.

#8
12-30-20, 02:41 PM
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Originally Posted by joed
A 10 amp rated receptacle is 10 amps no matter what the voltage.
nope. and THAT is what puts the inspector's knickers in a twist, isn't it?!

A cord rated for 10A at 240V is generally rated for 15A at 125V.

https://www.stayonline.com/category/...A8FB439D587EF6

#9
12-30-20, 03:57 PM
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If the plug has a dual rating then it has a dual rating. But if it only has one rating of 10 amp then it is 10 amps.

#10
12-30-20, 07:02 PM
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Generally, the IEC standards set maximums, and the cords that go into those receptacles are rated to 240V @ 10A, the rating at lower voltage depends on the gauge of the wires used.
Generally, they're interchangeable, as you'll see that older computer power supplies have a 120v / 240v slide switch, OR are listed as AUTOMATIC because they sense the chagne.
All modern power supplies now have power factor correction (PFC) so that red switch is a item of the past

Agreed. But the cheap knockoff cords are so thin that I wouldn't trust them with a sustained 20 amp / 125v load
I bought quite a few cords from dubious places I had one almost catch fire with a 6A load (intermittent load from a laser printer) I cut it open and it was mostly plastic coating the inner wires were only 22 AWG (if that!).

I also had one with no ground wire it had the "standard" PC style D-shaped IEC but only a NEMA 1-15P and no it was not the 2 wire version with the ground blocked off.

#11
12-30-20, 07:06 PM
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If an IEC receptacle is rated for 10A @ 250VAC, does this mean it is also only safe for 10A @ 125VAC? Or does the max amperage it can handle increase as voltage decreases?
That jack is rated for a maximum pole to pole voltage of 250v.
The contacts are rated to 10A.

#12
12-31-20, 06:05 AM
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The amp rating is to limit the risk of thing beeing to hot, so in this case do not load more than 10 Amp, usually witin a time limit of number of hours of continus max load.

#13
12-31-20, 08:10 AM
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Thanks for all the responses.
A little more digging and the actual rating of the receptacle is listed as: 15A @ 250VAC (IEC-UL/CSA); 10A @ 250VAC (VDE)

The company selling it advertised it as only being 10A but as you can see it has two different ratings based on two different standards. Can I go by the IEC-UL/CSA rating of 15A @ 250VAC?

Also, regarding load time: being an audio amplifier if the load ever even approached 15A total (which is highly unlikely but I'm just going by theoretical max possible) it would only be for short periods of time, like 1-2 seconds.

#14
12-31-20, 08:39 AM
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VDE tends to be more conservative in their ratings.

#15
12-31-20, 04:33 PM
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Thanks for all the responses.
A little more digging and the actual rating of the receptacle is listed as: 15A @ 250VAC (IEC-UL/CSA); 10A @ 250VAC (VDE)

The company selling it advertised it as only being 10A but as you can see it has two different ratings based on two different standards. Can I go by the IEC-UL/CSA rating of 15A @ 250VAC?

Also, regarding load time: being an audio amplifier if the load ever even approached 15A total (which is highly unlikely but I'm just going by theoretical max possible) it would only be for short periods of time, like 1-2 seconds.
I found the page for the IEC 60320 specifications on Wikipedia

The C13 is the standard for PC's and the like.
It looks like my "bootleg" cord with only 2 wires should have used the C17 end and not the C13 one like that was used I destroyed that cord inside was only 22 AWG wires.
Anyway good luck with your amplifier creation ventures.

VDE tends to be more conservative in their ratings
Yes 10A is more realistic for these connectors however 14AWG/3C cables with the C13 do exist.
The early Apple Powermac G5 computers used the C19 style connectors because they used about 12A @ 120VAC so the VDE ratings are more appropriate for the size of the pins.