PRINTED CIRCUIT BOARD CLEARANCE

BASED ON IPC-2221

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IPC-2221 is widely accepted throughout the world as a generic PCB design standard. The table below (which is not an official IPC table) is derived from "IPC 2221", Table 6-1, and provides recommended minimum spacing between conductors and component leads as a function of working voltage level and application. Note that IPC table gives the spacings up to 500V and provides formulas for the spacings above 500V. For your convenience, I added calculated spaces for voltages above 500V and added the columns with inches (IPC currently provides all distances only in metric units). For power conversion circuits IPC-9592 provides the following circuit board spacing requirements: SPACING (mm) = 0.6 + Vpeak x .005. For products covered by UL safety standards the creepage and clearance requirements of the respective UL/IEC standard shall take precedence over IPC.
Note that all IPC standards are voluntarily rather than mandatory. For more information see the Guide to PCB Spacing.
This page is for a general reference only and does not constitude a professional or a legal advice. Consult with respective standards for final design decisions.

	Bare Board								Assembly
	Internal layers		External conductors, uncoated		External conductors, uncoated, >3050 m		External conductors coated		External conductors with conformal coating		External component leads, uncoated		Component leads with conformal coating
Vpk, V	mm	inch	mm	inch	mm	inch	mm	inch	mm	inch	mm	inch	mm	inch
15	0.05	0.002	0.1	0.004	0.1	0.004	0.05	0.002	0.13	0.006	0.13	0.006	0.13	0.006
30	0.05	0.002	0.1	0.004	0.1	0.004	0.05	0.002	0.13	0.006	0.25	0.01	0.13	0.006
50	0.1	0.004	0.6	0.024	0.6	0.024	0.13	0.006	0.13	0.006	0.4	0.016	0.13	0.006
100	0.1	0.004	0.6	0.024	1.5	0.06	0.13	0.006	0.13	0.006	0.5	0.02	0.13	0.006
150	0.2	0.008	0.6	0.024	3.2	0.13	0.4	0.016	0.4	0.016	0.8	0.032	0.4	0.016
170	0.2	0.008	1.25	0.05	3.2	0.13	0.4	0.016	0.4	0.016	0.8	0.032	0.4	0.016
250	0.2	0.008	1.25	0.05	6.4	0.26	0.4	0.016	0.4	0.016	0.8	0.032	0.4	0.016
300	0.2	0.008	1.25	0.05	12.5	0.5	0.4	0.016	0.4	0.016	0.8	0.032	0.8	0.032
500	0.25	0.01	2.5	0.1	12.5	0.5	0.8	0.032	0.8	0.032	1.5	0.06	0.8	0.032
1000	1.5	0.06	5	0.2	25	0.99	2.33	0.092	2.33	0.1	3.03	0.12	2.33	0.092
2000	4	0.158	10	0.4	50	1.97	5.38	0.22	5.38	0.22	6.08	0.24	5.38	0.22
3000	6.5	0.256	15	0.6	75	2.96	8.43	0.34	8.43	0.34	9.13	0.36	8.43	0.34
4000	9	0.355	20	0.79	100	3.94	11.48	0.46	11.48	0.46	12.18	0.48	11.48	0.46
5000	11.5	0.453	25	0.99	125	4.93	14.53	0.58	14.53	0.58	15.23	0.6	14.53	0.58