Here's their link to their Electrical & Lighting section. If you want wires, click their Wire & Cable link.

or industrial supplier, not Lowe's or Home Depot. But I would be inclined to run conduit and pull stranded THHN wire vs. running romex. 4ga romex looks like it is 1-1/4 inch diameter, and that is going to be a beast to try and bend and pull through a house.

It does not appear that Lowes carries 4-gauge Romex wire. However, they do carry 4-gauge THHN (stranded) wire. You would have to purchase it by the foot (unless you want to spend $800+ for 1,000-foot spool), and you'd also need to install a new conduit for the THHN wire to run inside. That could be as simple as a flexible ("greenfield") conduit with a connector on each end. (See the image below - you can also purchase this from Lowe's.) I'm guessing your furnace runs off a double-pole breaker, so you will most likely need enough THHN cable to run 4 conductors (2 hots, a neutral, and a ground). I'd figure out your pathway, measure it, add a couple of feet to be safe, and then multiply that by 4. I'd probably purchase the green wire for the ground, and the black for the hots/neutral, and then use electrical tape on both ends of one hot conductor and a different color electrical tape on both ends of the neutral conductor so you can keep track of which one is which. Good luck...as BG said - don't work in your panel hot! Turn off the main breaker, but beware that even with that off, the feeders from the utility are always hot. Watch where your hands, screwdrivers, etc. are at all times! ** Edited by MP4VT2004 at 1/21/2026, 9:58:02 AM ** Edited by MP4VT2004 at 1/21/2026, 10:19:32 AM

for the conductors, one white for the neutral, and the green for the ground? I think your solution is spot on otherwise.

...Lowe's does not seem to carry red and white THHN wire. I do see now that they have blue wire. But the electrical tape trick will work. It's something I've seen actual electricians do on my jobsites, usually to keep track of phasing in a 3-phase panel...they try to evenly balance the load in the panel across the three phases, so I've seen them wrap the ends of black B-phase and C-phase hot conductors with electrical tape inside the panel so they can keep things straight. The image below provides the color standards, and the link provides more information: ** Edited by MP4VT2004 at 1/22/2026, 8:27:08 AM

w/Dominion Electric up here, probably could have gotten several different color wires for him. Personally, I would never try to do anything like that in a panel- I have an electrician friend on speed dial (that's not even a thing these days, is it lol!), and I can watch him do the install. I'll stick to wiring 3 way switches. ** Edited by PWR2LZ at 1/22/2026, 10:27:11 PM

One never knows if you need to run more wires through it...lol

...since he's running directly from his panel to his furnace, there really would be no need to run more wires in that conduit. If this was a home run conduit carrying multiple branch circuits, I would wholeheartedly agree that increasing the conduit size would be a great idea.

a different situation than you described

is the diameter. It will carry a larger amp loads for HVAC Units. As electricity travels it will lose current which is how fast the electron is traveling similar how fast water is moving in a river. ** Edited by jdkhokie at 1/21/2026, 9:48:16 AM

for you Hurley! You swapping the breaker and connecting it yourself too. Don't work hot, baby, life is too short!