Locking Disconnect Switch Cover - Requirements or Best Practices?

P

physensation

Member
Location
New Hampshire
Occupation
Electrical Engineer
Many disconnect switches include a provision to lock the cover itself. In the image below this is shown at the bottom right of the cover.

Is there an OSHA or NEC reference requiring locks on these to prevent unauthorized users from opening them and becoming exposed to live conductors? What best practices have you encountered in terms of style of lock to use on these?

Thanks for any thoughts!


image.jpg
 
From a local Significant Changes Class, this is new in the 2023 NEC. Code language is paraphrased to fit on one slide.

Slide66.JPG

A lot of switches similar to the one you have pictured cannot be opened while energized, is that the case with this one?
 
Don't tell anyone, but if you zip tie it closed, they will need a tool to cut the zip tie and therefore be compliant...
 
physensation said:
Is there an OSHA or NEC reference requiring locks on these to prevent unauthorized users from opening them and becoming exposed to live conductors? What best practices have you encountered in terms of style of lock to use on these?
Click to expand...
A lock on that switch will not prevent it from being opened if it's in the open position.
 
In large plants & hospitals if we were going to LOTO a safety switch or circuit breaker more then present shift we had to install a shackle that usually had six holes for other trades to install their own locks. Each lock had to have person & companies name & phone # on LOTO tag. I used a paint marker to place my name on the dozens of padlocks that I had. Our 6 man shop had a different color lock for each sparky and senior electrician & Forman had a master key to open our locks. .
 
NEC Inspector said:
From a local Significant Changes Class, this is new in the 2023 NEC. Code language is paraphrased to fit on one slide.

View attachment 2579778

A lot of switches similar to the one you have pictured cannot be opened while energized, is that the case with this one?
Click to expand...
Thank you, this reference is very helpful! I see this in 404.30 of the 2026 NEC. "shall be dead-front unless it requires a tool to access"
 
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