[deleted] t1_ir1eiso wrote on October 4, 2022 at 5:05 PM

[deleted]

Sparkykc124 t1_ir1px5z wrote on October 4, 2022 at 6:17 PM

I am an electrician and this is not true, at all.

Randomperson1362 t1_ir1mt8r wrote on October 4, 2022 at 5:57 PM

I'm not an electrician, so don't listen to me, but what is the harm in going with smaller wire?

Lets say you have 60 amp wire, then in a junction box you add connect 40 amp wire to lengthen the circuit. Assuming a 40 amp breaker* is that an issue?

Obviously using a 60 amp breaker is a very bad idea.

Princess_Moon_Butt t1_ir1ztv8 wrote on October 4, 2022 at 7:18 PM

Exactly. If you use wire that's rated for less than the breaker's capacity, yes, that's bad.

This guy's talking about using a 40-amp breaker, with a mix of 60-amp wire and 40-amp wire. There's no concern there, because the most that will go through that 40-amp wire is 40 amps.

eerun165 t1_ir1vd96 wrote on October 4, 2022 at 6:51 PM

Wire size can be increased in size to account for voltage drop.

Decreasing wire size from its corresponding breaker is a fire risk. The wire is not rated for the higher current and will heat up (think of the small wires in a toaster).

Viper67857 t1_ir324xm wrote on October 4, 2022 at 11:33 PM

It's still a 40A circuit on a 40A breaker, it just has wire rated for 55A along most of the run. Using a couple feet of 8ga at the end will not hurt anything.

You already downsize the massive 200A cables coming into your service entrance with 15-20A wires going to most of your devices, then those devices may have some tiny 20+ga wires inside them. You use what you need for the individual load, you don't just carry on the larger cable for consistency.