Laptop Cord from Adapter to Wall 125V vs 250V

[alwaystired5]

My Dell Inspiron N4010 laptop came with a cord that runs from the adapter to the wall outlet that specifies 10A, 125V. But that cord's third pin (the round pin at the top of the triangle) had broken out out and is missing. I am assuming that is the grounding pin? I found a cord with the same plug end, including the missing pin, but it specifies 10A, 250V. Can I still use the 250V cord, or will it damage my laptop charger/adapter? Sorry, I am not at all knowledgeable about these things.

 

[Harvey]

You can always use a power cord that is rated at a higher voltage than the maximum required by your setup. Your original cord was rated at 10A, 125V. The one you found is also rated at 10A, and it will handes 250V, twice the voltage it will actually encounter.

Bottom line - You should be good to go with the new cord.

 

[bonehead123]

You really should not use any cord that has has the grounding pin removed, especially with electronics, as this eliminates the safeguards the cord was designed to offer.

If you must do this because your receptacles don't have the (third) grounded port, you can get a 3 prong-to-2 prong adapter at the hardware store for less than $2....

You may also want to check if your dwelling is wired with or without a ground. If it is, then you should replace the current 2-prong outlets with 3-prong ones and make sure the ground wire is connected correctly.

If it is not, then there is not much you can do, except pray that you never get a high-voltage electrical discharge through your power lines (like lightening striking your house or a nearby transformer), cause it will completely fry anything & everything that is plugged in at that time.........

 

[Valantar]

You can always use a power cord that is rated at a higher voltage than the maximum required by your setup. Your original cord was rated at 10A, 125V. The one you found is also rated at 10A, and it will handes 250V, twice the voltage it will actually encounter.

Bottom line - You should be good to go with the new cord.

Unless my understanding of Ohm's law is completely off, isn't that wrong? After all, relative resistance (Ohm, &#937goes down as voltage increases (which is why long-distance power cables are run at several thousand Volts). Which means that at higher voltages, cables can be thinner.

Thus, a cable rated for 10A 125V has a resistance of 12.5 Ω (125V/10A), while a cable rated for 10A 250V has a resistance of 25 Ω. Thus, running that cable at half voltage (125V) also halves the current it can handle, as resistance is a physical property of the cable. A cable rated at 250V 10A thus is only rated to handle 5A at 125V (125 V/25 Ω=5A).

Of course, 5A at 125V is 625W. So you would still be able to run about ten laptops off that cable before reaching its limits. But as a general rule, you can run a cable at a higher voltage than its rating at the same amperage safely, but not at a lower voltage.


(Another example of this is that some modern smartphones run quick charging systems at higher voltages over the same cables that previously could only handle, say, 2A at 5V. Increasing voltage then allows you to pass more power through the same cable, without changing anything else. The Quick Charge system for Samsung's Note 4 runs at 1.67A at 9V, transmitting 15W over a cable that could previously only handle 10W (2A at 5V).)