dryerelectrical
I am hooking up a 4 wire cord to a 3 wire dryer. I don’t see a green screw but there are two other green cords with a stripe on them that I can’t seem to turn.
Where should the green wire from my cord go?
Those are the only other screws in that terminal area.
DO NOT connect the ground wire to the grounded (neutral) conductor, as this could lead to current flowing through the body of the dryer (and potentially through you).
The installation guide for the dryer will have wiring instructions for both 3, and 4 wire configurations. Check the manufacturers documentation for proper wiring, but I would say the first image is likely correct.
Instructions from random Maytag Installation Instructions (PDF)
After doing some research, and looking at dryer wiring diagrams. It turns out that the green/yellow wire is not a ground wire, it is a neutral to case bonding wire. When this wire is not in use (in a 4-wire installation for example), it is simply connected to the neutral terminal and is unused.
Getting power to the machine is the easy part. The neutral goes to the silver screw in the center, and the two hots go to the brass screws on either side. Now the machine is powered.
Safety ground is the hard part. You really want that.
If you have a 4-wire cable with NEMA 14-30, you're all set.
If you have a 3-wire cable with NEMA 10-30, you have several options, and the rest of this post is about that.
For dryers and stoves specifically, Code allows you to "cheat": bond ground to the neutral wire. The rationale is there are a lot of old NEMA 10-30's out there, and trouble is unlikely since dryers and stoves are rarely moved and plugs are rarely unplugged. The hazard is, if the neutral fails, it will energize the chassis of the dryer at 120V and will electrocute users, and has. Sometimes fatally.
Install a 4-wire cable to a 14-30. For a dryer circuit, Romex 10/3 is the right stuff, it sells for less than $1/foot. Follow the old wire and replace if feasible. If you're not comfortable going inside the service panel, leave about 4 feet of excess length and call an electrician to make the connections. If you prefer, you could run metallic or non-metallic conduit and use single-wire THWN wire (preferably stranded for easy pulling). Ground is optional in metallic conduit, the conduit is a legit ground path.
Replace the NEMA 10-30 outlet with a 14-30 by running a separate ground wire. It must be at least 10 AWG - single wire will do, but the wire must be bare, green or greeen/yellow, and re-marking another color is not allowed. Route however you can, to either the service panel inside on a ground lug, or to a ground screw inside a box in all-metal conduit that is continuous back to the service panel. This is covered under NEC 250.130(c). Don't connect anywhere else, e.g. not to 120V outlets, those have 12 or 14 gauge ground wires - too thin. You might be able to bond to a water heater's ground, but ask a code expert before you do that.
You cannot buy or hack a 240V-only dryer (which takes NEMA 6-30) and replace your plug and re-designate the white wire to be ground instead. Electrical code does not allow that. You can remove the insulation, but you must remove all of it - hard to do in jacketed Romex.
If you install any wire or grounds, get a book on wiring installation and learn how to do it properly and legally, so the wire is not damaged and any electrician who touches it won't want to tear it out and redo.
Best Answer
I'd try the hole on the back, behind the white wire
I'd try threading a 10-32 grounding screw into the open hole on the back side of the wiring compartment and using that to land your ground. If that hole's the wrong size, then I'd get a Garvin GSST and carefully drive it into the sheet metal enclosing the wiring comparment, then land the grounding lead from the cord on that.