Voltage drop

[tomspark1]

Yes, that is frequently the way things are done. But it would not make any difference, in the situation described by the OP.

But the OP is talking about running two lengths of wire before hitting the first load. In that circumstance, it does not matter whether the larger wire comes first or second.

But doesn't it stand to reason that if the less efficient wire (12) is fed with a slightly higher voltage it is going to produce higher voltage at the end? If reversed the 12 drops more voltage before it gets to the 10 so even though more efficient it's still not getting as much to work with. Thanks for all your responses btw

 

[weressl]

I wouldn't choose making a splice over using the larger size the whole way . . .

. . . especially making a splice in the conduit!

I agree, but the whole idea is cracked to begin with. It is possible but not practical.

 

[LarryFine]

But doesn't it stand to reason that if the less efficient wire (12) is fed with a slightly higher voltage it is going to produce higher voltage at the end?

One problem with relying on VD to regulate voltage is that the voltage will vary inversely with load, possibly being damaging under a light (opposite of heavy, not dark) load.

If reversed the 12 drops more voltage before it gets to the 10 so even though more efficient it's still not getting as much to work with.

In spite of instinct, it does not matter which size conductor is closest to the source or the load. The total voltage drop will depend on the total circuit resistance and the total load current.