FED-STD-228A
Method 3212.1
18 APRIL 2014
TENSILE STRENGTH AND ELONGATION, MEDIUM HARD-DRAWN
OR HARD-DRAWN CONDUCTORS
1. SCOPE
1.1 This method is intended for use in determining the tensile strength and elongation of medium hard-
drawn and hard-drawn solid copper or copper alloy conductors or wires of stranded conductors of
insulated wire and cable. It is applicable to both coated and uncoated conductors and wires.
2. SPECIMEN
2.1 When the diameter of the conductor is over 0.208 inch, the specimen should be a 20-inch length of
the copper conductor or wire from the stranded conductor taken from the inspection unit. When the
diameter of the conductor is 0.208 inch and less, the specimen should be approximately 80 inches in
length taken from the inspection unit. For elongation tests the specimens should be free from joints.
3. APPARATUS
3.1 The apparatus shall be as follows:
3.1.1 Testing machine as described in method 3211 except that the testing machine shall be equipped
with the wedge-type grips, and the power-actuated grip shall be adjusted to move at the rate of 2 ± ½ inch
per minute.
3.1.2 Steel scale graduated to 1/64 inch or finer, or its decimal equivalent.
4. PROCEDURE
4.1 The general procedure shall be as described in method 3211, except that the power-actuated grip
shall move at the rate of 2 ± ½ inch per minute.
4.2 Elongation of wire with nominal diameter of 0.208 inch or larger shall be determined as the
permanent increase in length, due to the breaking of the wire in tension, measured between bench marks
placed 10 ± 1/64 inch apart on the specimen as described in method 3211.
4.3 The elongation of wire with diameter less than 0.208 inch shall be determined by measurement made
between the grips of the testing machine. The zero length shall be the distance between the grips when
a force equal to 10 percent of the specified tensile strength shall have been applied and the final length
shall be the distance between the grips at the time of rupture. The zero length shall be as near 60 inches
as practicable. The fracture shall be between bench marks in the case of specimens so marked and
between the grips of the testing machine when specimens approximately 60 inches in length are involved,
and not closer than 1 inch to either the bench mark or either grip of the machine.
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