How to pull wire over ceiling

1. Are your running the wire parallel to the joists or across the joists? In other words are you going to have to drill the joists?

The best thing to get is to go to Harbor Freight and get a package of the fiberglass fishing rods use to fish wire. They come in a package for around $20. They are about 30" long. You can buy Klein or Milwaukee at HD or Lowes as well and they make fancy ones that glow but a lot more $$$$$. The HF ones have worked very well for me. There is plenty in the package to run 20'

If you are running with the joists and you make 2 holes you should be able to go 20' if no blocking or cross bracing bothers you.

If you perpendicular to the joists its much harder. You would have to drill every joist, or use wire mold etc.

Is this first floor or second floor do you have a basement or attic you can run it through and then fish up or down?

is the ceiling drywall or plaster?

Flat, swirled or spray on popcorn?

What size wire, what size sub panel?

Pop the recessed lights out. Use those holes and then put them back.

I've done a lot of drywall repair work. You most likely have to drill a hole in the top plate or floor joist. I have a set of electrician's 4 foot drills. If you have to cut a hole in the drywall, this is how I do it.

I mark a 6" square and put 2 lines across one edge so I know how it came out so I can cement it back as it was removed. I make my cut at a 45 deg angle at all four sides so that it doesn't fall thru when it is put back. I will use a fine hacksaw blade to make the cuts. Sometimes, I will use a large 1/4" thick paint stick I get free from Home Depot and cut it at 9" and put it across the hole and use a drywall screw at each end to secure it to the hole so that the patch that you cut out rests against it when you replace the plug.

I use drywall mud straight from the container (not mixed with water) and smear it on the cut hole and on the 4 edges of the plug and place it in the hole. I use 2 drywall screws to secure the plug to the paint stick. Remove the excess mud and let dry. When dry sand with 80 grit sandpaper. Mud again for a perfect finish and paint.

They do make an ultra thin drywall tape if you want to tape over the four cuts on a smooth wall. I don't and not on a textured wall. I match the texture.

Pulling the wire and going around a corner. I use steel fish (wire) tape but sometimes I prefer fibreglass rods that I got from Harbor Freight for peanuts. I also use nylon cord that I got from Home Depot on a spool and try and catch that and pull the cord thru the holes and attach that to the wire and then pull the wire while pushing it from the other end. Trying to catch the wire with fish tape can be frustrating, especially in a wall with insulation.

Knowledge not shared is a sin.

A lot of interesting comments from people who've never done this before and/or even looked at the picture.
You don't say where the wire is coming from and where it's going after it passes thru.
Parallel run will be easier, IF there's no solid blocking. There will be some kind of blocking but it may be metal bridging.
I personally wouldn't pull a sub panel service cable thru, fish style and let it lay on the drywall. There's no protection for the wire.
Best/proper way. With a chalkbox, snap 2 parallel lines about 6" apart. Cut them with a razor knife or multi tool, remove the drywall to expose a channel.
With a right angle drill, drill each joist in the center. You still may have to drill a top plate or some other way to get the wire in the wall unless you're passing thru to an unfinished space.
Pull your wire, drywall patch, tape, paint the ceiling. You're going to need a good taper otherwise you'll see that joint forever.
Are you sure there's no other way to route the wire for the subpanel, including on the exterior?

To respond to the other commenters:
1. I wouldn't fish a sub panel wire that big and let it lay on the drywall.
2. Wire that big doesn't come in MC, nor can you put it wire mold, only properly sized conduit.
3. There aren't enough recess lights to use that idea/method.

With regard to @HydronicMike 's item 2 above — quite correct. In restoration work I use flexible conduit for that size (for that matter, 8 gauge and up) and run the wire (THHN) in that. You can also use rigid (sort of) conduit, but in restoration work that can get difficult — to put it mildly.

Smaller wire I use armored cable ("BX"), same insulation class.

Not, mind you, that NM-B is bad cable. Great stuff. It's why arc fault interrupter circuit breakers were invented… Mice and other cute little critters just love to nibble on it.

There will be joists running one direction as illustrated below. Level of difficulty is based on if you are going in same direction as joists or having to drill holes in joists to pass wires through.

You may also be dealing with engineered 2X4 Truss joist which are simple to pass cables through; see below.

if you are running a subpanel you really need to read the code. it is online. it will tell you what protection what wiring methods need. tech flex won't do it for any line voltage wiring. larger cables have exceptions to some of the protection rules but I would try to get it at least somewhat protected. I wouldn't want to do it on the exterior both for aesthetics and protection of the wire from UV(it is supposed to be uv resistant, it is better not to test that). For #6 wire individual conductors in conduit may be easier to get in to a tight space than cable.

You can get type MC in just about any size you care to order, albeit maybe not at a big box store. 8/4 is a little over $5/ft, see https://www.wireandcableyourway.com/8-4c-mc-cable-aluminum-armored-metal-clad-cable-250ft-or-1000ft-spool for instance. Pay particular attention to the clamps, I've seen soooo many runs with clamps that can't be tightened down properly because they're not made for the cable type and/or they're the wrong size.

Around here, nearly everything can be done under a homeowners' permit, which includes X number of inspections. Presumably more inspections could be bought if necessary. Check with your building dept. if you haven't already.

& the best glow rods to use are the https://www.snapav.com/shop/en/snapav/lsdi-trade%3B-creep-zit-trade%3B-30-ft-threaded-connector-wire-running-rod-kit They're stiff enough to push across a ceiling (not like those limp large-diameter things that I see guys struggling to use all the time) and flexible enough to shove through a few ¾ EMT 90°s in a pinch. Tape a loop of pull string on the end & use a foot or two of ceiling grid wire with a tiny hook on one end & you'll see why they're called magic sticks around here.

(URLs are just the first google results I found, nothing special.)

If you are DIY wiring, I would get the US equivalent (can also get the Canadian one as 95% same) of this:

https://psknight.com/residential

Guessing the proper way to wire things up generally doesn't end well.

Around me typical outdoor subpanel feed is done with Teck ( PVC-jacketed MC) cable as it is flexible, armored and can be buried. With the current costs, almost all of it is aluminum.

Wire above the ceiling penetrating the joists needs no protection if the edge of the cable is at least 1 1/4" from the edge of the joist. They make wire protection plates you can use if you are less than 1 1/4".

Going through a masonry wall its good practice to sleeve the cable in PVC. If you need 80 amps I would run #2 SER cable aluminum.

You can go outside the house and back in with SER

As I mentioned above SER cable. You will go broke buying copper in larger sizes,.

You should look at the load because if you really need 80 ams it going to get pricy.

60C is only for nm cable afaik

I'm kind of wondering what the need for a subpanel 20 feet away is. Seems like an expensive way to get something done.

80 Amp sub panel and cheap 🤣

both the cable and the terminals in the panels and on the breaker need to be rated at 75c to use the 75c column.

if i am reading the code right, ser cable can be used at the 75c if both of these are true:

1. It does not pass through any insulation
   AND
2. all of the current carrying terminals it will connect to on both panelboards and the breaker are rated 75c.(the ground probably does not need to be 75c. the minimum ground size will come from the table in the code)

if you used raceway, ent might be most cost effective, you would buy thhn or xhhw wire or something like that.