3 prong to 4 prong dryer cord switch
#1
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3 prong to 4 prong dryer cord switch
Hi. I am changing an electric dryer power cord from a 3-wire cord to a 4-wire cord. I have attached the red, white and black as I know I should, but there is a white wire attached to the ground screw and I am not sure how to proceed. I know I need to attached the ground wire to the ground screw, but what do I do with the white wire currently attached to the ground screw? I have pictures attached, but in case you cannot see them, next to the ground screw there is an arrow pointing to the screw with the words "external ground connector". Advice is welcomed and appreciated.


#4
Your model number is incomplete and doesn't turn up under Kenmore. Can you check it and post.
The cord ground will be attached to the external ground screw. Just want to check existing white wire on a schematic.
The cord ground will be attached to the external ground screw. Just want to check existing white wire on a schematic.
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Thanks Ray. I will wait for PJ, but if it comes to needing to ohm out the white wire, I will need instructions. I have an ohm meter and can check an outlet or a battery, but will need to know just how to do this.
#8
Set your meter to the lowest ohm scale. Zero your meter.* Disconnect the white wire under the ground screw. Measure from the white wire to the ground screw. If it shows continuity leave in place. If it doesn't measure to the neutral terminal. If it shows continuity move the white wire to the neutral terminal. I'm reasonably certain it will show continuity to the neutral terminal.
*Your meter should show 0 ohms when the probes are touched together (full scale movement of the needle on analogs). If not you move the adjustment wheel.
*Your meter should show 0 ohms when the probes are touched together (full scale movement of the needle on analogs). If not you move the adjustment wheel.
#9
I found the manual. See bold type below. Remove white wire from external ground screw and replace with cord green. Move white wire to center terminal.
This dryer is manufactured ready to install with a 3-wire
electrical supply connection. The neutral ground wire is
permanently connected to the neutral conductor (white wire)
within the dryer. If the dryer is installed with a 4-wire electrical
supply connection, the neutral ground wire must be removed
from the external ground conductor screw (green screw), and
secured under the neutral terminal (center or white wire) of
the terminal block. When the neutral ground wire is secured
under the neutral terminal (center or white wire) of the
terminal block, the dryer cabinet is isolated from the neutral
conductor.
A 4-wire power supply connection must be used when the
appliance is installed in a location where grounding through
the neutral conductor is prohibited. Grounding through the
neutral is prohibited for (1) new branch-circuit installations,
(2) mobile homes, (3) recreational vehicles, and (4) areas
where local codes prohibit grounding through the neutral
conductors.
This dryer is manufactured ready to install with a 3-wire
electrical supply connection. The neutral ground wire is
permanently connected to the neutral conductor (white wire)
within the dryer. If the dryer is installed with a 4-wire electrical
supply connection, the neutral ground wire must be removed
from the external ground conductor screw (green screw), and
secured under the neutral terminal (center or white wire) of
the terminal block. When the neutral ground wire is secured
under the neutral terminal (center or white wire) of the
terminal block, the dryer cabinet is isolated from the neutral
conductor.
A 4-wire power supply connection must be used when the
appliance is installed in a location where grounding through
the neutral conductor is prohibited. Grounding through the
neutral is prohibited for (1) new branch-circuit installations,
(2) mobile homes, (3) recreational vehicles, and (4) areas
where local codes prohibit grounding through the neutral
conductors.
#10
Brian, Thanks for the heads up on this. Wish I had this info yesterday. Customer bought a 4 wire cord to replace 3 wire cord for his dryer. I told him he needs to check the grounding path but I did not know the specifics. He kind of shrugged if off. 
He was going from a 50 amp cord to a 30 amp. Apparently the original cord was jury rigged by a previous owner and the prongs were forced (bent) into the female receptical. Needless to say the unit shorted out.

He was going from a 50 amp cord to a 30 amp. Apparently the original cord was jury rigged by a previous owner and the prongs were forced (bent) into the female receptical. Needless to say the unit shorted out.
#11
Hey Norm,
Notice Ray was correct even without the manual. When removed from the frame, the white wire would show continuity to the neutral terminal, and NOT show continuity to the frame.
There is another method manufacturers use that is more common than this white wire IMO. The more common method:
- Neutral terminal will be bonded to the chassis with a bare metal strap.
- To convert to 4 wire, you will remove bond strap from chassis, then connect cord ground to chassis
Notice Ray was correct even without the manual. When removed from the frame, the white wire would show continuity to the neutral terminal, and NOT show continuity to the frame.
There is another method manufacturers use that is more common than this white wire IMO. The more common method:
- Neutral terminal will be bonded to the chassis with a bare metal strap.
- To convert to 4 wire, you will remove bond strap from chassis, then connect cord ground to chassis