3 prong range outlet

Question

I wired a 3 prong range outlet using 8/2 wire. I had a black insulated, white insulated, and a bare single strand copper wire. In the outlet I wired the black wire to one hot side and the white wire to the other hot side. I wired the bare copper wire to the neutral prong. For the breaker I used a 2 phase 40amp breaker and wire the black wire to one side and the white wire to the other side. I then wired the bare copper to the ground bar ( not the neutral). Is this correct or should I redo it in a different manner?

Answer 1

For an old installation, there are some "shortcuts" grandfathered in, but even those are based on "no ground but have a neutral". You have the opposite - and much worse - problem of "no neutral but have a ground".

• Rip out the 8/2 and put 8/3 in place. That will give you two hots (typically black & red), neutral (white) and ground (bare or green).
• Replace the 3-prong outlet with a 4-prong outlet NEMA 14-50. This has connections for 2 hots, neutral, ground.
• Replace the 3-prong cord with a 4-prong cord. You will likely have to make a small change inside the range to separate ground and neutral.

What you have right now is unsafe on many levels. It happens to work because on a typical range the neutral carries relatively little current most of the time. But it violates code in several ways:

• White should not be hot.
• Ground and neutral should be separate.
• Neutral should be white or gray, and definitely never bare.
• New installations should always use a 4-prong outlet.

Answer 2

You can't do that. That's been outlawed since 1989.

You need to redo the circuit using 8/3 cable (or 6/3 if you aim to breaker it for 50A).

You need to wire a separate neutral/ground and bring it into a NEMA 14-50 receptacle (if you use receptacles, that's not required).

You also need to jumper the oven for a 4-wire connection, which means removing a jumper between neutral and ground.

Why?

The pre-1989 wiring was a throwback to the 1960s before any grounding was done at all. Appliance manufacturers argued that big appliances don't need grounding because it would ruin appliance sales if everyone had to rewire their house to replace an appliance. When asked "How do we ground the appliance, then", the manufacturers said "To the neutral" (i.e. bootlegging ground; which was never allowed anywhere else). Their logic was that ranges and dryers were rarely plugged in and were unlikely to fail.

Of course, if the neutral wire does fail, this neutral-ground bootlegging guarantees the chassis becomes electrified the moment you open the oven door or start the dryer. And yeah, this kills people.

It's usually put in the newspapers as "faulty wiring" but that's not true. Faulty wiring is when you connect it wrong from the start. There's nothing faulty about a wire that merely breaks. Electrical wiring is meant to be resilient, and a simple wire break is normal enough that it shouldn't create a hazard. The NEMA 10 style wiring you just did violates that principle.

If the inspector doesn't fail this inspection, he or the buyer will getcha when you try to sell the house. Might as well fix it now when you have access to the route. Also for safety.

Answer 3

Electric ranges use a three wire 220v/110v circuit with a neutral wire splitting the voltages between the hot legs. There is also supposed to be an earth ground, which is a fourth wire.

The old code allowed the ground wire to be omitted, but that is ancient history. Not acceptable for new work. Pulling 8/2 wire was incorrect.

Wiring the bare copper grounding conductor to the neutral prong is incorrect. The neutral must be an insulated wire. When you have the correct neutral wire, it should be connected to the neutral bar of the breaker box, not the grounding bar. In the current configuration, you are running current through the ground bar, which is not great.

Connecting the white wire to the hot leg of a circuit is not safe, someone might think it is neutral and electrocute themselves or cause a fire. Your wiring will also look like 110v but be energized with 220v. Hopefully whoever works on it next will notice they had to turn off a 220v breaker, but they might not!