How do I wire a 220v-4 wire breaker box connection to a 3 wire piece of equipment?

Answer 1

The only place that white neutrals should be connected to the ground wires is upstream of all branch circuit breakers at the ground bus bar inside the main breaker panel.

The answer given below gives DANGEROUS ADVICE because it fails to explain exactly what a separate ground wire does.

Where they are provided in a circuit - such as in 4-wire 240 volt outlets - the green or bare copper ground wires must be kept separate from the neutral (white) wires everywhere except in the main breaker panel at a single point upstream of all circuit breakers.

The whole purpose of providing a ground wire in a circuit is for it to be connected directly to any the internal metal frame and external metal casings of all appliances which it supplies with power.

Then, if an accident occurs which causes physical damage to the appliance (or its connecting cord or plug) - or if some electrical insulation fails or some other kind of breakdown occurs, which could make the appliance catch on fire or electrocute the user - the ground wire is there as a safety wire to "ground" the fault condition.

The result is: before any further damage is caused to users or their home, the heavy fault current the ground wire takes will make the circuit breaker trip to cut off the electricity.

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In normal households in North America and other countries which use the same 60 Hz supply service -

4 wires are Red (Hot), Black (Hot), White (Neutral) and Bare (Ground)

3 Wires are Red (Hot), Black (Hot), Green (Neutral/Ground) - generally not used for 220-240V - or may be Black (Hot), Red (Hot) and Bare (Ground) or Black (Hot), White (Hot), Bare (Ground).

The following advice is dangerous and should not be followed:

There is NO difference between the White, Green, or Bare wires. They all get connected to the same place in the breaker box - the neutral strips on the sides of the box. Use of the bare ground is for personal safety only - however the white or green wire does the exact same job.

So to answer your question

(Breaker Wire : Appliance Wire)

Red : Red

Black : Black

White : Green

Bare - connects to the frame or case of the outlet/box you're wiring into.

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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.