J asked in Science & MathematicsEngineering · 2 months ago

# Does amperage go up if a larger wire is used?

If you have something that requires a 14 gauge wire, and replace it with 6 gauge wire, this means that resistance decreases a lot, which according to ohms law should raise the amperage.

But everywhere I check on the internet, people say that bigger wire doesn't have much of an effect.

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• 2 months ago

If the 14 ga wire is large enough to carry the current then the amperage won't change much.

Larger wire is useful in two cases.

1. If there is a very large current.

2. If the run is a very long distance.

Look at the wires into any Home. Usually there is 200A service which is a large current and the run from the transformer to the house may be up to 3oo feet or even more.

Large wires are necessary and are 4-O or even 2-O wires.

• Anonymous
2 months ago

The current won't increase.

With the larger conductor size, its voltage drop will be less, so there will be slightly higher voltage at your device.  Depending on the length of your wires, that voltage might only be a few hundredths or tenths of a volt higher.  If it's a very long distance, the difference might be a few volts.

• 2 months ago

It won't have much of an effect.

The main thing that you gain by going with heavier wire is that you can run it further without experiencing as much voltage drop.

• 2 months ago

Well, yes. Wires have a certain amount of resistance depending on their cross-sectional area. That's one of the reasons we have bigger wires for a motor than for a 40-watt lamp. But there comes a time when increasing the wire size does not make enough difference to justify its extra cost and extra effort in installation.

• Anonymous
2 months ago

If the voltage is the same, a thicker wire will have a lower resistance, and thus a higher amperage

• Anonymous
2 months ago

For the ten-thousandths time....................LOAD IS CURRENT  LOAD IS CURRENT   Say it with me    LOAD IS CURRENT  Paint it on the wall    LOAD IS CURRENT   Shout it from the roof top.   LOAD IS CURRENT   Or, look it up in Glover Pocket Ref.

• Dixon
Lv 7
2 months ago

Thicker wire can carry more current before melting but the actual current in a proper circuit should depend on the load not the wire gauge. The general rule is that wire resistance should be negligible compared to the rest of the circuit, so making it thicker just makes it more negligible.

The only time wire resistance does/should have effect is for extreme lengths of wire, such as might be found in wound components like relays, motor coils etc.

• 2 months ago

The current is determined by the total resistance, which in this case is the load plus the wire resistance.  unless you are using much too thin a wire, the effect is small.

an example, a 15 amp load at 120 volts is 8 Ω

now if you have 100 ft of #14 wire that is 0.26 ohms

100 ft of #6 is 0.04 Ω

total R with #14 is 8.26 Ω, I = 120/8.26 = 14.5 amps

total R with #6 is 8.04 Ω, I = 120/8.04 = 14.9 amps

yes, goes up, but only by 2.5%

• 2 months ago

Depends on the load and the supply.  IF the load is constant there is less loss in thicker wire but no more current is drawn out of the supply.

• 2 months ago

The change in resistance is trivial so there is no change in flow.  The wire was not maxed-out before.  If it had been (if the current was limited because of wire resistance), then increasing the cross-sectional area (larger gauge) would allow more flow. If you have a resistance-governed current limitation, there is almost always lots of heat.  The wire tends to burn out fast when that is the case.  It acts as a fuse. Starts fires maybe.

Usually, the current is limited by whatever the wire is feeding.  Your wire simply has to be large enough to easily supply that amount of current without frictional heating.  Making it larger won't increase the demand at the far end.  You can, however, exceed the safe capacity of a wire by adding more energy-users at the end.  Then you would be well-advised to increase the wire gauge.