Can I use a removable breaker lockout clip?

Not to satisfy the code. NEC 110.25 requires the provisions for locking to remain in place with or without the lock installed, so the hardware must be permanently mounted.

Does a lockable breaker replace a disconnect within sight?

Only where the applicable section permits it. Where a section requires the disconnect to be within sight, Article 100 defines that as visible and not more than 50 feet distant, and a lockable breaker elsewhere does not comply.

Which sections require a lockable disconnect?

Common ones include NEC 422.31(B) for appliances, 430.102(B) for motors, 440.14 for air conditioning equipment, and 620.51(C) for elevators, all of which point back to 110.25.

Does a breaker need to be a special type to lock open?

Not a special breaker, but you do need a specific kind of locking accessory. Section 110.25 of the 2023 NEC is short and it is the section that trips people up, because it does not care whether a padlock is installed. It cares whether the thing that accepts the padlock stays attached to the breaker.

The exact requirement

Section 110.25 states that where a disconnecting means is required to be capable of being locked in the open position, the provisions for locking shall remain in place with or without the lock installed. In other words, the lockout hardware has to be a permanent part of the equipment. A universal breaker lockout that you clamp on during the work and take home in your tool bag afterward does not satisfy 110.25, because the moment you leave, the provision for locking is gone.

The fix is a listed lockout accessory that screws to the breaker or to the deadfront and stays there permanently, or a breaker or enclosure that comes from the factory with a lockable handle mechanism, or a lockable enclosure door. Most manufacturers sell a low cost, breaker specific lock off kit that mounts with a screw and stays put.

Where the requirement comes from

Section 110.25 only applies when some other section requires the disconnect to be lockable. Several do. Section 422.31(B) requires a permanently connected appliance rated over 300 volt amperes to have a disconnecting means, and where the disconnect is out of sight from the appliance it must be capable of being locked in the open position per 110.25. Section 430.102(B) covers motor disconnects and its exception permits a remote disconnect where it is individually capable of being locked in the open position with provisions that remain in place per 110.25. Section 440.14 covers air conditioning and refrigeration equipment disconnects. Section 620.51(C) covers elevator disconnects. Section 700.10 and Section 645.10 have their own lockable requirements.

Lockable is not the same as within sight

The common design decision is whether to install a local disconnect at the equipment or to use a lockable breaker at the panel. Article 100 defines in sight from, or within sight, as visible and not more than 15 m (50 ft) distant from the other. Where a code section requires the disconnect to be within sight, a lockable breaker at a panel around the corner does not satisfy the rule no matter how good the lockout hardware is. Read the specific equipment article before deciding.

Handle ties and multipole devices

For a multiwire or multipole circuit, the lockout has to hold all the ungrounded conductors open. A two pole breaker with a common trip handles that with one lockout. Two single pole breakers with a listed handle tie under Section 240.15(B)(1) can be locked as a unit if the lockout accessory is sized for the tied handles.

Field takeaway

Use a listed, permanently mounted lock off kit for the specific breaker. If the accessory can be removed without tools and taken away, it fails 110.25. And confirm whether your equipment article wants lockable or within sight, because they are different requirements.