Texas Electrician ExamTexas journeyman & master

Checked against primary sources 2026-08-24

Somebody has to be able to switch it off, and see that they did

The code asks the same question in twenty different articles. Learn the question once and you can answer the item without knowing which article it came from.

On this page
  1. The question every disconnect rule is asking
  2. In sight from is a defined term with two halves
  3. Where the requirement lands
  4. The lock that stands in for line of sight
  5. How the item is usually built
  6. What to do with this before test day
  7. What this page cites

The question every disconnect rule is asking

Someone is going to work on this equipment, and the code wants them to be able to kill the power and then confirm with their own eyes that it stayed dead. Everything about disconnecting means comes out of that.

It is not one rule. It is the same idea written down separately in the article covering services, the article covering motors, the article covering air conditioning equipment, the article covering appliances, and a dozen more. Each version is tuned to the equipment it governs, which is why the code never gathered them into one place.

For an open book test that arrangement is good news, because it means the equipment named in the item tells you which article answers it. Identify the equipment, turn to its article, find the part headed disconnecting means, and read. You are looking up one page, not searching.

In sight from is a defined term with two halves

Article 100 defines it, and the definition is a pair of conditions rather than a distance. One piece of equipment is in sight from another when it is visible from it and when it is no further away than a stated limit. Read the limit in your own book, because it is a number worth having in your hand rather than in your memory.

The pair is the whole point. An installation can satisfy one condition and fail the other, and an item that describes a plan view with a wall in it is testing precisely that. A disconnect twenty feet from a controller with a partition between them fails on visibility while passing on distance. A disconnect you can see clearly down a long bay may fail on distance while passing on visibility.

Notice that visibility is assessed as built rather than as intended. A door that is kept shut is shut. Shelving in front of a disconnect is in front of it. The definition does not ask what the installer meant.

This is also why the definition itself gets tested directly. Definitions, Theory and Plans carries three scored items on the journeyman knowledge portion, and a term defined in Article 100 that reappears in fifteen other articles is exactly the kind of thing a definition item is built from.

Where the requirement lands

A motor branch circuit has four separate protective jobs and they are sized from different numbers Left to right: the branch circuit short circuit and ground fault protective device, then the disconnecting means, then the controller, then the overload device, then the motor. The conductors, the disconnecting means and the short circuit device are all sized from the table full load current. Only the separate overload device is sized from the nameplate full load amps, which is a different number. Confusing the two is the most common calculation error on this topic, and getting it backwards puts an undersized conductor behind a correctly sized breaker. supply OCPD discswitch ctrl overload M short circuit and ground fault conductors and this device: sized from the TABLE full load current running overload this one only: NAMEPLATE amps the two numbers are rarely equal, and the exam knows it
Four devices, two different current values. The table value sizes the wire and the breaker. The nameplate sizes the overload. Drawn against NEC 430 Parts II through VII, and 430.6(A)(1). Values live in the 430 tables.

The drawing above is a motor branch circuit, and the disconnecting means is the second element in it. That position matters. The disconnect sits between the protective device and the controller, so opening it leaves the controller and everything downstream dead while the branch circuit device stays where it is.

Article 430 is the busiest version of the rule and the one worth reading first, because it protects two different people at once. Someone working at the controller needs a disconnect they can see from the controller. Someone working at the motor, or at the machinery the motor drives, needs the same assurance at that end.

The number to tab is NEC 430.102, titled Location. That is where the in sight from test lands on a motor circuit, and 430.102(A) is the subdivision the rest of the book points back at. NEC 440.14 sends you there for air conditioning equipment, and NEC 430.208 sends you there for motor circuits over 1000 volts, so one tab answers three articles.

Two of those get confused constantly. A condensing unit on a roof looks like a motor problem and is answered from the air conditioning article, because the compressor inside it is sealed with its motor and has no horsepower rating for the motor tables to work from.

The lock that stands in for line of sight

Where the code lets a lockable disconnect substitute for one you can see, it is buying the same protection by a different route. You cannot watch the handle from where you are working, so instead nobody else can move it while your lock is on it.

The condition attached to that permission is the one candidates drop. The means of locking has to stay with the equipment whether or not a lock is fitted at the time. A hasp that travels in somebody’s van is not a provision for locking, and a breaker that will only accept a lockout accessory nobody left on site is not lockable in the sense the code means.

Read that as a piece of engineering rather than as paperwork. The substitution only works if the locking hardware is there on the day the next person arrives, which is usually years after the installer has gone.

How the item is usually built

There are only a few shapes, and once you have seen them the wording gives the shape away.

Notice that none of those are arithmetic. Disconnecting means items reward reading, and they punish answering from a picture in your head of how the last job was wired.

What to do with this before test day

  1. Tab the definition of in sight from in Article 100 and read the distance limit once, out loud, so you know it is two conditions and not one.
  2. Tab the disconnecting means part of Article 430, which is the longest treatment in the book and the model for the rest.
  3. Read the disconnect rules in Articles 422 and 440 back to back, since those are the two most likely to arrive dressed as something else.
  4. When an item describes a layout, sketch it in the margin of your scratch paper before you read the options. The wall is easier to see in a drawing than in a sentence.

That is about forty minutes of work and it covers a subject area of its own plus a share of the largest area on the outline.

What this page cites

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Every rule here is cited to the section it comes from, and corrections are logged in public with the date. This is study material rather than electrical advice, and it does not replace your own code book or your inspector.