What's the difference between 10 2 wire and 10 3 wire?

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asked Nov 3, 2020 in Do it yourself by Dimitri (960 points)
What's the difference between 10 2 wire and 10 3 wire?

1 Answer

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answered Nov 4, 2020 by GrinJule (1,740 points)
The difference between 10-2 wire and 10-3 wire is in the amount of wires in the wire and what it's used for.

10-2 wire is a 10 AWG wire size that has 2 wires that are insulated and then 1 wire for the ground.

So with 10-2 wire the wires would be 2 hot wires and a ground.

10-3 wire refers to wire that has 3 insulated wires inside it and a bare copper ground wire.

10-3 wire usually has a black wire, red wire and a white colored wire.

10-3 wire is used commonly where you need a neutral and 2 hots or where you have a light switch at the top of the stairs and a light switch at the bottom of the stairs that operate one light.

A 10-2 AWG wire can carry up to 30 amps of electricity.

When you install a 10-2 wire it can handle 50 amps but only for a short time such as on startup.

However if you have something is gonna pull 50 amps on startup you likely need a 50 amp circuit breaker and should use the 8 AWG wire size.

Copper also carries more amperage than aluminum does and smaller copper wire can safely carry more amps than larger aluminum wire.

10-2 AWG Copper wire is rated for 30 Amps in most installations.

50 Amps calls for 6 AWG Copper wire or 8 AWG high temperature cable.

12-2 copper wire carries up to 20 amps on 120 volts but you can also use 12-2 wire to run 220 volt circuits which means that 12-2 copper wire can then carry the 30 amps just fine.

I have 12-2 copper wire on my electric water heater.

I was concerned but it has been fine and never has the wire heated up.

I consulted with an electrician about it and he said that it was not recommended to install 12-2 wire on the water heater but it is safe to do so.

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