What are breaker lock outs for. I often seem installed but they aren’t locking anything out. I also know its impossible to prevent a breaker from tripping if it needs to trip. So what are they for?

ppe during service, repair or replacement

There are lock-outs and lock-ons. Lock-ons keep someone from inadvertently turning off the CB. Lockout as Barry stated are for installing a lock to keep the CB in the off position during maintenance, repair, etc.

Thanks Barry. You are always so helpful. I did not really explain it well. Here is what I was talking about.


Those are used in instances when you don’t have a disconnecting means within sight of an appliance, machinery, etc. and allow for a lock to be installed.

Ok thanks!!

Lock Out-Tag Out is an OSHA requirement and there are a multitude of devices that attach to breakers, valves, plugs, etc. to lock out energy sources so they can be worked on safely.

Lock On’s are usually used to prevent inadvertent flipping of breakers. Happens when general lighting breakers are located adjacent to the server or HVAC breakers. Creates havoc.

Robert’s telepathy has you covered :mrgreen:

Any appliance that does not have a disconnect within sight of that appliance will require a lockout be installed on the overcurrent device by the NEC.
This is for non-motor appliances such as cooktops, built in ovens, and the most common, water heaters.

If the appliance has a motor then the disconnect must be within sight of the appliance such as air handlers and air conditioners.