A-DOME-The top surface of the insulator.
B-CROWN-The portion between the dome and the wire groove.
C-BASE or RIM-The surface of the insulator upon which it rests.
D-THREADS- Spiral grooves in the pinhole corresponding to matching grooves in the pin, allowing the insulator to stay securely fastened to the pin. (Threading can also be on the inside of the skirt.)
E -BASE OF THREADS -The point nearest the base of the insulator at which the threads begin.
F-PETTICOAT or INNER SKIRT-An extra band of glass (or porcelain, etc.) at the bottom of the insulator, increasing the leakage path from the wire to the pin.
G-DRIP POINTS -Points or beads around base (resting surface) of the insulator which were supposed to attract moisture, from where it would drip off
H-UMBRELLA- An overhanging ledge on the insulator below the wire groove, meant to increase the leakage
I-EMBOSSING- Raised letters or numbers anywhere on the surface of the insulator.
J-THREADED PINHOLE -The cavity inside the insulator into which a threaded pin is secured.
K-EARS -Projections on top of the insulator to keep the line wire in place.
L-SKIRT -The portion of the insulator below the lowest wire groove.
M-SADDLE or CABLE GROOVE-An indentation in the dome of the insulator which holds the wire or cable.
N-EYES-Holes in the ears of the insulator
A Few Other Insulator Parts, Not Illustrated
Only one representative CD number is given for each example..
RIBS-Two or more small vertical ridges meant to strengthen the lower wire groove ridge. (CD 106.3)
TURRETS-Regularly spaced block- or round-shaped projections (miniature battlements) at the top of the insulator. (CD 206)
CLAW-Regularly spaced twisted finger like projections on the top of the insulator. (CD 206.5)
RIDGES-Narrow horizontal projections (one or more) placed on the top of two opposite sides of the umbrella, meant to deflect water from the line wire. (CD 288)
FLUKES/FLUTES-Regularly spaced vertical outward projections (flukes) or indentations (flutes) at the wire groove meant to keep the tie wire away from the body of the insulator. (CD 130.1)
O-WIRE GROOVE -The indentation where the tie wire is attached.
P- HORIZONTAL or VERTICAL RIDGE-Regularly spaced narrow projections on the dome or skirt (or both), meant to deflect rocks, etc., causing less damage to the body of the insulator.
Q-THREADS ON INSIDE OF SKIRT- Ridges designed to increase the linear surface or to help drain moisture away from the pinhole.
R-WIRE GROOVE RIDGES-Projections directly above and below the wire groove (called “upper” and “lower.”)
