Din Rail Mounted Circuit Breaker is Exposed.


Senior Member
My point exactly, is there anything that can be done to make it safe. the people going into these cabinets, some of them don't know what a circuit breaker is. I just want to make sure everyone is safe.
No different than a homeowner removing his panel

tom baker

First Chief Moderator
Staff member
At the traffic signal shows I used to attend, the mfgs of “pluggables”, conflict monitors, load switches loop detectors traffic controllers did not and would not get any of those products UL listed due to the cost and complexity as there is no demand for it.
What I experienced in Washington state the inspectors would come out to inspect a signal and inspect the service and then open up the signal cabinet and nothing was listed and the job would stop. This was typically for a signal like at Walmart where they had just paid $200,000 for the signal and needed to get it turned on so they can open the store. The issue would go up the chain of command and will come back down to approve the signal, of course the reason it wasn’t approved is nothing in the cabinet was listed,
As a result in Washington state we have a state code rule that allows the municipal jurisdiction to accept responsibility for the equipment and wiring in the cabinet, there is a formal process for that.


Staff member
San Francisco Bay Area, CA, USA
Electrical Engineer
Those are not IEC style DIN rail breakers, that’s a Square D QOU surface mount type, which became DIN rail mountable some years ago. The “pitch” (distance between poles) is not the same as it is in IEC breakers, so none of the accessories for those will work.

You CAN get finger safe covers for the terminals of QOU breakers. You may have to buy more than you need, I believe they come in a bag of 40, but they are cheap.



Senior Member
Northern illinois
I have seen these style of breakers mounted in a small junction box through the door which has cutouts for just the handles. They were mounted on a channel that is tall enough that the breaker just touches the back of the door.

I never thought it was worth the effort but it does create a totally enclosed circuit breaker with no exposed live parts.

I have put other stuff inside junction boxes inside control panels where I knew people were likely to be working live on other things since I know that very few people will bother to suit up.

But you cannot truly protect people from being unsafe who insist on being unsafe. Eventually it is going to catch up with them, no matter how many finger safe terminals you use, or insulating barriers you put in. The unsafe will find a way to hurt themselves or someone else.