How to Replace or Convert Bosch Dryer Power Cord

Before you start#

• Tools: Phillips screwdriver or nut driver for the terminal cover, a flat-blade screwdriver, and wire strippers if the cord ends need trimming.
• Part: a UL-listed 4-prong or 3-prong dryer cord rated for 30 amps.
• Safety: Unplug the dryer and switch its breaker OFF before starting — never work the terminal block live. This is a 240V circuit capable of a lethal shock.

Step by step#

1. Pick the right cord. Look at the wall outlet: four slots is a 4-prong NEMA 14-30 (current code), three slots is a 3-prong NEMA 10-30 (older homes). Buy the cord that matches the outlet.
2. Open the terminal block. Remove the terminal-block cover on the back of the dryer (usually 1-2 screws at the lower rear). The block has three or four points where the cord wires land.
3. Note and remove the old cord. The layout is: left terminal a hot (red or black), center terminal neutral (white), right terminal the other hot. On a 4-prong setup the green ground goes to the frame ground screw, separate from the block; on a 3-prong setup a bonding strap ties the center neutral terminal to the frame ground. Loosen the terminal screws and remove the old cord.
4. Connect a new 4-prong cord. Red to one hot terminal, black to the other, white to the center neutral, and green to the frame ground screw. REMOVE the bonding strap between neutral and frame ground, because a 4-prong cord has its own dedicated ground.
5. Connect a new 3-prong cord. The two hot wires go to the outer terminals and the neutral or center wire to the center terminal. INSTALL the bonding strap between the neutral terminal and the frame ground, since a 3-prong setup has no separate ground and neutral does that duty. Tighten every terminal screw firmly with no bare wire showing past the terminal.
6. Secure and test. Route the cord through the strain relief on the back panel and tighten its clamp so the cord cannot pull out, then refit the terminal cover, plug in, restore the breaker, and run a cycle to confirm normal operation.

If something is wrong#

• Trips the breaker immediately: a hot wire is on the wrong terminal (ground or neutral) — recheck the wiring against the diagram on the terminal cover.
• Mild shock when you touch the cabinet: the bonding strap is wrong for the cord type — removed for 4-prong, installed for 3-prong.
• Plug fits loosely in the outlet: the receptacle contacts are worn — have an electrician replace the outlet; it is not a cord fault.

Why 3-prong and 4-prong both exist#

Older homes were wired with a 3-prong (NEMA 10-30) dryer circuit where the neutral conductor also served as the ground, which is why a 3-prong cord bonds neutral to the dryer frame. Modern code separates those roles: a 4-prong (NEMA 14-30) circuit carries a dedicated ground wire in addition to neutral, so the frame is grounded independently and a fault on the neutral cannot energize the cabinet. That is the whole reason the bonding strap moves — it ties neutral to the frame on a 3-prong setup and must be removed on a 4-prong one, because the 4-prong cord brings its own ground. Getting that single detail right is what keeps the dryer cabinet safe to touch.

Seat the strain relief properly#

Do not skip the strain relief where the cord enters the back panel. A cord that can be tugged loose eventually works a terminal screw loose too, and a loose 240-volt terminal arcs, overheats, and can start a fire. Clamp the relief snugly on the cord jacket — not on the individual conductors — so any pull on the cord is taken by the clamp and never reaches the terminal block.