Connect a 14-2 to a 10-2
 

The gauges are so different. Should I solder them together or twist them together and cap them

If either was done you would limit yourself to a 15 amp breaker from using 14-2. 10-2 is usually on a 30 amp breaker and a fire hazard would result if 14-2 connected to it.

It is possible to twist them together but not the easy job if you have never done it. Strip lots of copper and try bending the #10 around the #14.

What is it your really trying to do?
I'd hate to see someone get hurt.

I'm tring to run 100 feet of 10-2 to a new outlet at the end of my driveway. The existing outlet had a 14-2 and will be using for power

Why 10-2? Seem a little over kill for just an outlet? What do you plan on powering?

I'm using it. 10-2 will prevent more loss of volts. Correct?

Sure, but the voltage drop depends on what load you have on the circuit. At only 100 feet I don't think you'd have to worry about it.

For a 100' run (200' total circuit length):

• #14 = 0.505 ohms
• #12 = 0.318 ohms
• #10 = 0.200 ohms
• (source)

Voltage drop, assuming a 15 Amp load (max for #14):

• #14 = ~7.5 volts
• #12 = ~4.8 volts
• #10 = ~3.0 volts

Whether the 4.5 volt difference is worth the extra cost and trouble of using #10 is up to you.

Where are you from? If from Canada, the voltage drop is limited by code to 3% on a branch circuit.

It is just a recommendation in the states, not a code issue.

That's why I posted that. Doesn't say in his profile

Is the total length 200?

Live in virginia

Just use wire nuts, align the ends and install wirenut.