This is a good question and a common issue when dealing with modern breaker types like QO plug-on neutrals and AFCI/DF breakers with larger handles and test buttons. The older style lock-offs were designed for standard breakers and often don't fit well with the newer designs.Here are a few things to consider and some potential solutions

1. Lock-Off Compatibility:
Specific Model Numbers

The critical thing here is the specific model number of the lock-off device you're using. Many generic lock-offs won't work. You need to find lock-offs specifically designed for QO breakers, especially ones with AFCI/GFCI features.

Manufacturer Documentation

Check the manufacturer's documentation (product sheets, websites, etc.) of the lock-off device to see if it lists compatibility with QO breakers and, even better, if it mentions specifically being compatible with AFCI or DF breakers. This is crucial.

Online Reviews

Scour online reviews for the lock-off device you're considering. Look for comments from other electricians who have used it with QO AFCI/DF breakers.

Local Electrical Supply House

Talk to your local electrical supply house. They should be familiar with common issues and may be able to recommend specific lock-offs that they know work. They often have demo units you can try.

2. Potential Lock-Off Solutions



Eaton CHMLO - Compatible Lock-Off

Eaton CHMLO breakers have a lock-off device that attaches to the panel cover, and then locks over the handle to keep the breaker from being turned on/off.

Square D (Schneider Electric) Specific Lock-Offs

Call your local Square D supply house and inquire about the correct lock-off for the breakers. Square D typically offers various lock-off devices. Look for part numbers specifically designed for QO AFCI/DF breakers. Be prepared to provide the specific breaker model number.

Custom Solutions

If you're handy, you might consider modifying an existing lock-off, but only if you can do so without compromising its structural integrity or ability to securely lock. This is generally not recommended unless you are very experienced and confident in your ability to modify the device safely.

Consider Larger Lock-Out/Tag-Out Devices

These are larger, more industrial-style lock-out devices that clamp onto the breaker and are designed to accommodate larger breaker handles. They're a bit bulkier, but they may be the only option that works reliably.

3. Code Compliance and Disconnecting Means



NEC Requirements

Review NEC 422.31 (for appliances) and other relevant sections for requirements regarding disconnecting means. You need to ensure your lock-off solution meets these requirements. The disconnecting means must be readily accessible and capable of being locked in the open (off) position.

"Readily Accessible" Definition

Keep in mind that "readily accessible" means capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, and so forth. The lock-off must be readily accessible to qualified personnel.

4. Appliance Cords as a Last Resort (and when Permitted)



Code Restrictions

Check the NEC and local codes regarding appliance cords for dishwashers and range hoods. Generally, they are not permitted for hardwired appliances unless specifically listed and labeled for cord-and-plug connection. Usually only dishwashers have a version designed to be cord-and-plug connected. Range hoods are almost always hardwired.

Listing and Labeling

If appliance cords are permitted, the appliance must be listed and labeled for cord-and-plug connection, and the cord must meet specific requirements for size, type, and length. The receptacle must also be readily accessible.

5. Best Practices



Documentation

Document everything you do, including the lock-off device model number, breaker model number, and any modifications you make (if any).

Photos

Take photos of the installation to show compliance with code.

Consult with an Inspector

If you're unsure about any aspect of this, consult with your local electrical inspector before* you complete the installation. They can provide guidance on acceptable solutions in your area.

In summary, finding the correct lock-off device that is compatible with QO AFCI/DF breakers is the key. Start by contacting Square D and Eaton directly and your local electrical supply houses and be prepared to provide them with the breaker model numbers and the specific application. Avoid using appliance cords unless absolutely necessary and permitted by code. Flag for review