Qualified Personnel in control cabinet

nietzj

Member
In a control cabinet that has both line voltage (120v or greater) and low voltage (less than 50 volts) when can a low voltage or limited power tech work without supervision? It is my understanding that if there is a barrier that separates or protects against exposure to line voltage the low voltage tech can work unsupervised. With any exposure to line voltage you must have a electrical license or be supervised by a licensed electrician. Does this sound right?
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Engineer
In a control cabinet that has both line voltage (120v or greater) and low voltage (less than 50 volts) when can a low voltage or limited power tech work without supervision? It is my understanding that if there is a barrier that separates or protects against exposure to line voltage the low voltage tech can work unsupervised. With any exposure to line voltage you must have a electrical license or be supervised by a licensed electrician. Does this sound right?
There is no single set of national rules that govern this situation.
Generally standards like OSHA and NFPA simply require workers to be "Qualified" for the tasks they are performing. It is up to each company to create an Electrical Safe Work Practices program which establishes their own requirements. Simply 'being licensed' will rarely be viewed by OSHA as equal to 'being qualified".
 

nietzj

Member
There is no single set of national rules that govern this situation.
Generally standards like OSHA and NFPA simply require workers to be "Qualified" for the tasks they are performing. It is up to each company to create an Electrical Safe Work Practices program which establishes their own requirements. Simply 'being licensed' will rarely be viewed by OSHA as equal to 'being qualified".
Thanks Jim,
I do understand there are electricians who may have acquired their license under questionable circumstances but generally speaking a class A journeyman is in my opinion qualified. As for the PLT license that includes everything from landscapers and carpenters to highly skilled limited energy techs.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Engineer
Thanks Jim,
I do understand there are electricians who may have acquired their license under questionable circumstances but generally speaking a class A journeyman is in my opinion qualified. As for the PLT license that includes everything from landscapers and carpenters to highly skilled limited energy techs.
Please read the definition of Qualified, found in the NEC, NFPA 70E, and various OSHA standards. You will find that none of them use the word electrician, much less licensed or journeyman.
It is up to your company to determine the requirements for qualification based on the task being performed.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
In a control cabinet that has both line voltage (120v or greater) and low voltage (less than 50 volts) when can a low voltage or limited power tech work without supervision?
Why would it matter what the guy's job title is? Unless it is a union thing.

It is my understanding that if there is a barrier that separates or protects against exposure to line voltage the low voltage tech can work unsupervised.
This could be a union or company rule.

With any exposure to line voltage you must have a electrical license or be supervised by a licensed electrician. Does this sound right?
This could also be a union or company rule.

There is no electrocution hazard if an employee is not exposed to hazardous voltages. Since < 50V is not considered hazardous, pretty much any one can work on it without PPE for dealing with an electrocution hazard, short of a contractual situation or employer's rule.

The thing is that regardless of job title, the exact same PPE is required as is the exact same determination that the employee is "qualified" to perform the work.
 
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cornbread

Senior Member
A big part of being qualified is the ability to recognize the hazard. Back in my day is was easy to look at a panel and see what control wiring was verses power wiring. The old NEMA stuff, it was easy to look at a panel and see the difference. With the new IEC stuff it?s more difficult. We recently purchased a machine from a European vendor. One of more experienced guys was poking around the control panel not realizing it had 480V wiring. The darn cabinet had a 480V to 24VDC power supply, go figure. The 480V contactor looked like a cheap control relay, the 3 phase breaker had the look of a DIN rail mounted breaker one would use for control. Here we had a guy that was experienced but clearly not qualified to be working on that machine. With all the above said, we did install some labels & physical barriers in the panel to protect folks from the majority of the 480 Volt stuff. This experience was a real eye opener for me; experience has nothing to do with qualifications. How do you teach someone to recognize a hazard exists? We are trying o get our guys to pull prints and look them over before they dive head long into a troubleshooting mode, know and understand what voltage levels are where. We are doing our best to put warning labels on all panels with mixed voltage. All it takes is for one panel to slip thru the cracks.
 
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