NEMA and IEC Standard Taper and Connection Sizes for Graphite / Carbon Electrodes

Material Specifications and Characteristics

The following are standard of NEMA & IEC 3, 4 TPI Taper standards, and male / female size connection sizes for Manufactured graphite and carbon electrodes.

3 TPI Taper Connecting Rod
Electrode Nominal Diameter		Diameter (Maximum)		Length (Maximum)
in.	mm	in.	mm	in.	mm
9	225	5.5	139.7	8	203.2
10	250	5.5	139.7	8	203.2
10	250	6.125	155.58	8.667	220.13
12	300	6.125	155.58	8.667	220.13
12	300	6.975	177.17	10.667	270.93
14	350	6.975	177.17	10.667	270.93
14	350	8.5	215.9	12	304.8
16	400	8.5	215.9	12	304.8
16	400	9.5	241.30	14	355.6
18	450	9.5	241.30	14	355.6
18	450	10.75	273.05	14	355.6
20	500	10.75	273.05	14	355.6
20	500	10.75	273.05	18	457.2

4 TPI Taper Connecting Pin
Nominal Diameter of Electrode		Diameter (Maximum)		Length (Maximum)
in.	mm	in.	mm	in.	mm
3	75	1.8125	46.04	3	76.2
4	100	2.75	69.85	4	101.6
5.125	130	3.125	79.38	5	127
6	150	3.625	92.08	5.5	139.7
7	175	4.25	107.95	6.5	165.1
8	200	4.813	122.24	7	177.8
9	225	5.5	139.7	7	177.8
9	225	5.5	139.7	8	203.2
10	250	6	152.4	7.5	190.5
12	300	7	177.8	8.5	215.9
14	350	8	203.2	10	254
14	350	8.75	222.25	14	355.6
16	400	8.75	222.25	14	355.6
18	450	10.625	269.88	14	355.6
18	450	10.625	269.88	18	457.2
20	500	10.625	269.88	14	355.6
20	500	10.625	269.88	18	457.2
20	500	11.75	298.45	18	457.2
24	600	12.5	317.5	14	355.6
24	600	12.5	317.5	18	457.2
28	700	9.5	374.65	18	457.2
28	700	14.75	374.65	22	558.8

Male / Female
Nominal Diameter of Electrode		Male End				Female End
Nominal Diameter of Electrode		Length		Pitch Diameter		Socket Depth		Pitch Diameter
in.	mm	in	mm	in.	mm	in	mm	in.	mm
7	175	4.112	104.44	2.931	74.45	4.313	109.54	6.30	160.02
8	200	4.688	119.06	3.329	84.55	4.813	122.24	7.167	182.04
9	225	5.188	131.76	3.779	95.99	5.313	134.94	8.08	205.23
10	250	5.668	144.46	4.112	104.44	5.813	147.64	8.88	225.55