IPC Class 2 or Class 3: which one does your PCB need?
The difference between the IPC classes, what they mean for plating, annular ring and inspection, and how to decide.
What the IPC classes are
IPC is the industry association whose standards define how printed circuit boards are designed, built and accepted. The class describes the reliability the product needs, from the lowest requirement to the highest.
| Class | Typical products |
|---|---|
| Class 1 | General consumer electronics; function is what counts |
| Class 2 | Dedicated-service electronics where a long, uninterrupted life is expected — the usual baseline for industrial and most commercial products |
| Class 3 | High-reliability electronics that must not fail: medical, aerospace, military, safety-critical industrial equipment |
Which standards matter
- IPC-6012 is the qualification and performance specification for rigid boards; it contains the class requirements.
- IPC-A-600 is the visual acceptance standard used to judge what is found on a finished board.
- IPC-2221 is the generic design standard, covering for example spacing and the current capacity of traces.
- IPC-A-610 is the acceptability standard for electronic assemblies (boards with components), also in three classes.
What changes between Class 2 and Class 3
- Hole plating: the average copper in plated holes is about 20 µm (0.8 mil) for Class 2 and about 25 µm (1 mil) for Class 3.
- Annular ring (the copper ring around a hole): Class 2 allows the hole to break out of the pad by up to 90°; Class 3 requires at least 50 µm of copper around the hole on outer layers and 25 µm on inner layers, with no breakout.
- Acceptance criteria: Class 3 tolerates fewer and smaller imperfections such as voids, and requires a larger margin around holes.
- Inspection and cost: the stricter checks lower the yield and raise the price.
How to decide
- Ask what a failure costs: an inconvenience, a repair, or a risk to people.
- Check whether your customer or a regulation prescribes a class.
- If there is no requirement, Class 2 is the right and economical choice for most products.
- Choose Class 3 only if the application needs it — it is not "better" in general, it is stricter and more expensive.
What PCB-ELECTRA does
Every board gets a 100% electrical test (short circuit and open circuit, flying probe) and AOI, and our production is certified to ISO 9001:2015 and ISO 14001:2015. Our capabilities include IPC-A-610G for assemblies (Classes 1, 2 and 3). Name the class you need when you ask for an offer, so that we can confirm the requirements for your design in advance. See capabilities and how a board is built on the double layer and 4-layer pages. For an offer, use the price calculator or contact us.
Frequently asked questions
What are the IPC classes?
IPC defines classes 1, 2 and 3 of increasing demands: class 1 for general products, class 2 for dedicated service products and class 3 for high-reliability products.
Which class do I need?
It depends on the product and on your customer’s requirements. Class 2 suits most industrial electronics; state the class in your request and we confirm it.
Is an IPC class a certificate?
No. It is a set of acceptance criteria that you and the manufacturer agree on for the board.
Browse the questions and answers →
See our manufacturing capabilities
Minimum trace and spacing, drill sizes, materials, tolerances and tests for every board type, on one page.
Open the capabilities →Ask an engineer
Not sure what applies to your board? Describe it in a few lines and our engineers will advise you.