# FCC Part 15 Class A vs Class B: Which Applies to Your Product?

FCC Part 15 divides unintentional radiators into two classes with very different emission limits — and choosing the wrong one means either a product that can't be sold in residential environments or a failed retest that sends you back to the lab. This short explains the Class A versus Class B distinction, how to determine which applies to your product, and why erring on the wrong side is expensive.


## Transcript

### Why the classification matters

When you test to FCC Part 15, you'll test to either Class A or Class B limits — and the difference isn't a paperwork formality. Class B limits are tighter, and certifying to Class A by mistake means a full retest. Get it right.

### Class A vs Class B explained

Class A covers digital devices marketed exclusively for commercial or industrial use. Class B covers anything that may be used residentially — a deliberately broad standard covering most consumer and dual-use products. Class B limits run six to ten decibels tighter, affecting PCB layout and shielding. Switching from Class A to Class B is a new authorization, not an amendment — meaning a full retest.

### The decision rule

When in doubt, test to Class B. Meeting tighter limits at the design stage costs far less than a full retest after certification. If your product could ever end up in a home, through any channel, Class B is the right call.

Tags: FCC, Part 15, Class A, Class B, EMC