Unplug the Whipper Snipper's power cord to avoid injury while replacing the wire spool.
Turn the Whipper Snipper upside down so the bottom of the trimmer faces up.
Press the locking tabs on the spool cover toward the center of the spool. Lift off the spool cover.
Lift the old wire spool out of the spool compartment.
Remove the tape from the end of the new wire spool. Insert the new wire spool onto the shaft in the spool compartment. Feed the end of the wire through the hole in the side of the compartment.
Replace the spool cover. Press it down until the cover locks into place.