Can panelboards be equipped with control circuits?

In an NFPA protective clothing class I'm attending, there was a question about what type FR clothing should be worn when working on a
125VAC energized control circuit. From the job hazard analysis matrices we were handed out, the only mention of "control circuits" were for MCCs(motorized control centers). The descriptions of typical jobs in 240VAC or less panelboards didn't mention any control circuits....just energized parts.
Yes, the question is vague and poorly worded...yes, in the real world, I would know whether I was working on a panelboard or a MCC or some sort of other cabinet. I guess my question boils down to whether NEC's definition of a panelboard can include the use of a control circuit enclosed within? I googled panelboard and "control circuit" together and didn't seem to find any relevant hits.
Any examples or model numbers if such a beast exists would be appreciated. Also, if someone knows the NEC and OSHA's 1910 backwards and forwards and knows that control circuits aren't in panelboards, I'd appreciate a reference.
Thanks in advance.
Danny
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wrote:

Generally speaking the panelboard is the assembly inside the cabinet that holds the overcurrent devices. If the cabinet was large enough it could also contain other equipment. I have seen assemblies that include the service disconnect, branch circuit O/C protection and MCC equipment in one cabinet. The sewer lift pump controllers you sometimes see on the side of the road is one example. It comes as a listed assembly. For the purposes of arc flash protection this is really a distinction without a difference. You should be protected for the available arc hazard, no matter what kind of equipment you are working on.
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Control circuits do exist in panelboards in the form of controlled SCR's on the mains, CT's on the branch circuits, etc. These panelboards should be listed by a nationally recognized testing lab like UL and the contol contractor installing the controls should have a UL certification. The phrase "control circuits" doesn't mean much. You have to go by the Class. Class 2 control circuits are not a shock and fire hazards in a nonclassified (nonhazardous) environment. However Class 1 control circuits are. For further info read Article 725 in the NEC.
I talked to an OSHA man in Washington DC several years ago about NFPA70E. He said that OSHA asked the NFPA to write the document, but that they were having difficulty getting it adopted. Some major players are complaining that calculating the available fault current is not an exact science, and there are four computer programs that do the calculation but they do not give the same answers.
At the IAEI NW Section meeting I went to about two weeks ago, they taught a 4 hour class on NFPA70E and the CFR's related to it. They stated the CFR's are performance standards that already require that workers protect themselves, but the CFR's do not give specifics. NFPA70E gives the specifics so if it is followed the CFR requirements will be met for this area. They stated that an electrician receives an electrical burn requiring medical treatment about once every hour for an 8 hour day or 40 injuries per week (USA.) That is significant. Accepting NFPA70E is going to take some time, but you can be rest assured it will become an accepted practice as time goes on.
Some basic rules are: Only qualified persons should be working on electrical circuits. This means they have received the training and have the experience to do the work. Work all circuits de-energized unless turning them off creates more of a hazard than working them hot. If you work them hot use the proper clothing and equipment to protect yourself from the energized circuits. This may require insulating the circuits from being contacted and insulating yourself so you do not come in contact. If you are working 480 volts hot, use a protective hood, insulated gloves (certified at 5kv), proper fire resistant clothing and insulated tools. If you are working voltages greater than 480 volts you should have specialized training for that work.
I have come very close to being seriously hurt by 480 volts twice in my life and when you consider a 40 year work history, one is very likely to get burned at least once in that time. I have been lucky, and that is all there is to it. During both near misses, I was in a hurry and did not take the proper precautions because I was trying to get the job done. Learning about NFPA70E is a big plus for electrical safety.
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