A composite wood component is comprised of a wood filler core having opposed parallel flat side and end surfaces and opposed parallel top and bottom surfaces. The system includes multiple pole-unit assemblies each of which is totally self-contained and generates a tripping signal in response to overcurrent conditions to operate a ground-potential operating mechanism. The carrier shafts are arranged distributed on a circumscribed circle radius of the rotor and are each configured to take up a plurality of filament bobbins.