Gauge wire for distance

[jimbo]

_I need to run about 170' of wire for a electric dryer, is 10-3 good or should be 8-3?_

[Dean Hoffman]

There's a voltage drop calculator here. I think 3% is still the recommended drop.

You should probably run 4 wires instead of three. You'll be ready if you want something else later. One is equipment ground. Two are for power. The fourth will be neutral for whatever timer and such the dryer will have.

[Marilyn Manson]

The "3" in 10-3 (or the "2" in 14-2) only refers to the electricity-conducting wires, not the ground.

IOW 10-3 with ground is a four wire cable.

I'm not sure you that can even buy 10-3 without ground these days, now that just about everything requires a neutral and a ground.

Since this sounds like a new installation, it requires a x-3 cable with ground, a 4 prong receptacle and a 4 prong cord. If it's a retrofit i.e. an extension of an existing 3 wire no ground branch circuit, then he still needs the 4 prong set-up, but I believe that he can get away with adding a ground at the junction box where the new wire connects to the old. That ground wire must be no smaller than 10 AWG and must be connected to:

- the panel the circuit is powered out of, or - a junction box in another circuit served by that panel which has a #10 or larger ground wire back to the panel, or - the Grounding Electrode System i.e. the bare wires from the panel to the ground rods/water pipe.

[John A. Smith]

After Bidenflation:

copper 10-3 w/g is ~$1.90/ft copper 8-3 w/g is ~$3.25/ft

Miss Trump yet?

[Ed Pawlowski]

Good point. Look what Trump did to copper prices

In after hours trading in New York, copper for delivery in March added to gains earlier in the day, hitting $2.8310 a pound ($6,240 a tonne), a

7-month high and up 8% over seven straight sessions of gains.

[Marilyn Manson]

At least we know the latest troll's (John A. Smith) modus operandi.

Every post, even if actually related to a.h.r will elicit a response like that one. Might as well get used to it. They have no life, so it's all Trump this, Trump that, even when folks come here actually looking for help..

Trump would piss on him if he every met him and he'd lap it up and come back for more.

[bud--]

3% branch circuit, 2%feeder, 5% total will provide "reasonable efficiency of operation" - as you said not required by the NEC

Seems tacky, but that is what the book says. Exposed #10 would have to be protected from damage.

[Marilyn Manson]

What seems tacky? Adding a ground wire to an ungrounded branch circuit has been an accepted practice for as long as I can recall.

Is it the 2nd and 3rd options that make you queasy?. ;-) Would you prefer a home run from the junction box?

[trader_4]

Four wires is required by code, has been since the 90s. Dryer is typically 30A, for that length run 10 is definitely out, per your calculator you get just over 3% drop with 8 gauge, so either 8 or 6.

[bud--]

Ordinary power wiring is pretty traceable. The separate ground wire can be difficult or impossible to trace. So you run a #10 ground wire from a laundry ckt j-box. It is concealed and finally goes into a basement and is split-bolt connected to the Grounding Electrode Conductor. That connection is not in a box, and far as I know doesn't need to be accessible. It can be in the ceiling and covered by sheet rock. If it goes to the service panel (a 3-wire laundry ckt can't be from a sub-panel), the panel may be recessed so the wire is concealed in the wall.

It can be as traceable as knob-and-tube wiring.

I have fewer problems with grounding 15/20A receptacles. I am not fond of the method for extending a circuit. You have a laundry ckt that is

4-wire at the receptacle and 3-wire at the panel.