Dimensions of Connecting Pins and Sockets 4TPI
	Connecting Pins
	Nominal diameter	Nominal Pin size			Overall Length "L"
	of electrode	"d1"	x	"L1"	Maximum	Minimum
Inches	4	2.750	x	4.000	4.000	3.938
mm	100	69.850	x	101.600	101.600	100.010
Inches	5.1/8	3.125	x	5.000	5.000	4.938
mm	130	79.380	x	127.000	127.000	125.410
Inches	6	3.625	x	5.500	5.500	5.406
mm	150	92.080	x	139.700	139.700	137.320
Inches	7	4.250	x	6.500	6.500	6.406
mm	175	107.950	x	165.100	165.100	162.720
Inches	8	4.812	x	7.000	7.000	6.906
mm	200	122.240	x	177.800	177.800	175.420
Inches	20	10.625	x	18.000	18.000	17.906
mm	500	269.880	x	457.200	457.200	454.820
Inches	22	11.750	x	18.000	18.000	17.906
mm	550	298.450	x	457.200	457.200	454.820
Inches	24	12.500	x	18.000	18.000	17.906
mm	600	317.500	x	457.200	457.200	454.820
	Electrode Socket
	Nominal diameter	Depth of		Length of	Nominal	Pitch of
		socket "L3"		thread "L2"	diameter	thread
	of electrode	Minimum		Minimum	"d2"	"P"
Inches	4	2.187		2.000	2.750	0.250
mm	100	55.560		50.800	69.850	6.350
Inches	5.1/8	2.687		2.500	3.125	0.250
mm	130	68.260		63.500	79.380	6.350
Inches	6	2.937		2.750	3.625	0.250
mm	150	74.610		69.850	92.080	6.350
Inches	7	3.437		3.250	4.250	0.250
mm	175	87.310		82.550	107.950	6.350
Inches	8	3.687		3.500	4.812	0.250
mm	200	93.660		88.900	122.240	6.350
Inches	20	9.187		9.000	10.625	0.250
mm	500	233.360		228.600	269.880	6.350
Inches	22	9.187		9.000	11.750	0.250
mm	550	233.360		228.600	298.450	6.350
Inches	24	9.187		9.000	12.500	0.250
mm	600	233.360		228.600	317.500	6.350
AS PER NEMA STANDARDS
IEC STANDARDS ALSO AVAILABLE