Originally Posted By: hgordon This post was automatically imported from our archived forum.
BUT FIRST let me explain what I saw and my CONCERN:
1. These are at 2 separate inspections.
2. The Circuit Breakers they were on were in the ON position.
3. When I found them, the "device" was behind the poles which caused me to want to try to "trip" the CB's...but guess what, the poles wont move!!
4. I understand that these devices are designed to keep the CB's in a LOCKED-OUT mode while OFF...but they can also be for a LOCKED-ON mode..hmmm? Would that mean that the circuit CANNOT TRIP?
5. Finally...I would appreciate a bit of "narrative" attached to your description of the device.
Originally Posted By: bbadger This post was automatically imported from our archived forum.
I agree with Greg entirely.
UL requires circuit breakers to be of a "trip free" design. Meaning a person could do anything they want to hold the handle in the on position and the breaker will still open internally.
Along with being allowed, in some areas certain circuits are required to have 'breaker locks'.
Breakers feeding fire alarm systems and emergency lighting are often equipped with breaker locks.
Here is a small part from the NEC that is about emergency circuits
Quote:
a separate branch circuit for unit equipment shall be permitted if it originates from the same panelboard as that of the normal lighting circuits and is provided with a lock-on feature.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: Joey D’Adamo This post was automatically imported from our archived forum.
hgordon wrote:
But does the possibility exist that this would not happen due to the pole being forced in the open position?
Next time you see a tripped breaker, try to push it into the on position without flipping it to off first. It will simply spring back into the centre. So I'm guessing holding back the handle makes no difference; it is just that once it's no longer restrained it will naturally want to spring into the centre.