# Chapter 84 vs Chapter 85: Where Machines End and Electronics Begin

Source: https://hscodescout.com/blog/2026-11-15-classify-chapter-84-vs-85-machines-electronics/

Cross-border operations guide · November 15, 2026


**Short answer:** Chapter 84 covers machines and mechanical appliances, and Chapter 85 covers electrical machinery and equipment. Both sit in Section XVI, and the line between them is the principal function: what the product principally does. Section XVI Note 3 says a composite machine is classified by its principal function. When the principal function cannot be determined, GRI 3(c) sends the tie to the heading that occurs last in numerical order, which usually means Chapter 85.

## The principal function decides

Chapter 84 and Chapter 85 both live in Section XVI, and the notes to the section do most of the work. Section XVI Note 3 says a machine that performs two or more functions, or a composite machine made up of two or more machines, is classified by its principal function. A machine that principally does mechanical work goes to Chapter 84. A machine that principally does electrical work goes to Chapter 85. The question is never what the product contains. It is what the product principally does.

The notes also settle the parts question. Section XVI Note 2(a) says parts that are themselves goods of a heading in Chapter 84 or 85 stay in their own heading, rather than following the machine they belong to. A motor that is itself a good of heading 8501 stays in 8501, even when it is built into a machine of Chapter 84. A part that is not itself a good of a Chapter 84 or 85 heading follows the machine, under Note 2(b), if it is suitable for use solely or principally with that machine.

## Why the tiebreaker favors 85

When the principal function cannot be determined, the classification falls back to GRI 3, and the fallback inside GRI 3 is GRI 3(c): the heading that occurs last in numerical order. Chapter 85 headings carry higher numbers than Chapter 84 headings, so a genuine tie goes to Chapter 85. That is not a policy choice. It is arithmetic, and it is why close calls between the two chapters usually land in 85.

The smartwatch is the product that shows the rule in action. A smartwatch tells time, which points to Chapter 91, and it transmits data, which points to heading 8517. CBP rulings have classified smartwatches under 8517.62, on the ground that the principal function is communication, not timekeeping. The timekeeping is a feature. The communication is the function. That is the principal-function test applied to a real product, and it is the test that decides the close cases.

## The exclusions that override everything

Chapter 90 Note 1(m) excludes goods of Chapter 90 from Chapters 84 and 85. A measuring instrument that would otherwise fit Chapter 84 or 85 goes to Chapter 90 if the note says so, and the note wins over the heading text. That is the pattern to watch: the notes override the headings, and the chapter notes override the section notes when they conflict. Read the notes before you read the headings, and read the exclusion notes before you read anything else.

The practical habit is to classify in this order: check the exclusion notes first, then the principal function, then the parts notes, then the tiebreaker. A classification that starts with the heading text and never reads the notes is a classification that will be wrong on the products that matter, because the products that matter are the ones that sit on the line. For the smartwatch case in full, [classifying a smartwatch, 8517 or 9102](https://hscodescout.com/blog/2026-11-14-classify-smartwatch/) walks the ruling, and [classifying a bicycle under 8712](https://hscodescout.com/blog/2026-11-14-classify-bicycle/) shows a case where the heading text alone settles it.

## Frequently asked questions

### What is the difference between Chapter 84 and Chapter 85?

Chapter 84 covers machines and mechanical appliances, and Chapter 85 covers electrical machinery and equipment. Both sit in Section XVI, and the line between them is the principal function: what the product principally does.

### What is the principal function test?

Section XVI Note 3 says a machine that performs two or more functions is classified by its principal function. A machine that principally does mechanical work goes to Chapter 84, and one that principally does electrical work goes to Chapter 85.

### Why do close calls between 84 and 85 usually land in 85?

Because of GRI 3(c). When the principal function cannot be determined, the tiebreaker sends the product to the heading that occurs last in numerical order, and Chapter 85 headings carry higher numbers than Chapter 84 headings.

### Where does a smartwatch classify?

CBP rulings have classified smartwatches under 8517.62, on the ground that the principal function is communication, not timekeeping. The timekeeping is a feature; the communication is the function.