Clearance from Electrical Panels
- Thread starter mac5631
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- Lockport, IL
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- Retired Electrical Engineer
Re: Clearance from Electrical Panels
The simple answer is ?no.? Reference is NEC 110.26(A). The rest of the answer is a question: ?How will you make sure that the panel will be turned off before anyone tries to work on it?? What you will need to do is convince the inspection authority that you have a good answer to this question.
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: Clearance from Electrical Panels
Bennie,
I can't seem to find that in the code book.
Please help me out!
Bennie,
I can't seem to find that in the code book.
Please help me out!
Re: Clearance from Electrical Panels
Equipment that requires being worked on while energized, does not exist. The word "require" is a demand implying there is no alternative. There is always an alternative, therefore nothing requires exposing live conductors while energized.
I posted a million dollar bond to anyone who could show me a system that could not be shut down.
Equipment that requires being worked on while energized, does not exist. The word "require" is a demand implying there is no alternative. There is always an alternative, therefore nothing requires exposing live conductors while energized.
I posted a million dollar bond to anyone who could show me a system that could not be shut down.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Clearance from Electrical Panels
Equipment likely to be worked on while energized does exist.
[ October 01, 2003, 09:19 PM: Message edited by: ryan_618 ]
I agree. I believe the phrase " likely to be worked on while engergized" is the article that we are trying to find compliance with.
Equipment likely to be worked on while energized does exist.
[ October 01, 2003, 09:19 PM: Message edited by: ryan_618 ]
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Clearance from Electrical Panels
When performing infrared scans on panelboards, it is required to be open and energized while performing this maintenance test.
When performing infrared scans on panelboards, it is required to be open and energized while performing this maintenance test.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Clearance from Electrical Panels
When certain problems arise, thermographic testing is "likely to be required". The text from the code is likely, not shall be or must. Likely is a word with many conotations, and you surely could poke holes.
The answer is, talk to the AHJ. He/she is the only opinion of the definition of "likely" that matters. Most consider likely to include all.
When certain problems arise, thermographic testing is "likely to be required". The text from the code is likely, not shall be or must. Likely is a word with many conotations, and you surely could poke holes.
The answer is, talk to the AHJ. He/she is the only opinion of the definition of "likely" that matters. Most consider likely to include all.
G
Guest
Guest
Re: Clearance from Electrical Panels
When I did electrical service work I had a supervisor. When he was an apprentice he worked at a hospital. He is a skinny man. He was probably 18 to 22 years old as an apprentice fresh out of High School.His duties (he claims) included crawling around the bussing and dusting it off while it was energized. The hospital chose not to de-energize the busses while Mr. Skinny dusted them off.
I have also watched PG&E (POCO) use a water cannon to rinse off the insulators on the high-tension primary wire towers. They choose not to de-energize them.
The POCO guys are all trained in bare-handing. They have had less booms since going to bare-handing. They decided it's safer to go bare-handed.
I am posting this for informational purposes, not to support any thesis. Carry on with the thread. Read this, and move along
When I did electrical service work I had a supervisor. When he was an apprentice he worked at a hospital. He is a skinny man. He was probably 18 to 22 years old as an apprentice fresh out of High School.His duties (he claims) included crawling around the bussing and dusting it off while it was energized. The hospital chose not to de-energize the busses while Mr. Skinny dusted them off.
I have also watched PG&E (POCO) use a water cannon to rinse off the insulators on the high-tension primary wire towers. They choose not to de-energize them.
The POCO guys are all trained in bare-handing. They have had less booms since going to bare-handing. They decided it's safer to go bare-handed.
I am posting this for informational purposes, not to support any thesis. Carry on with the thread. Read this, and move along
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Clearance from Electrical Panels
This is another case in which language fails us. There is no clear answer, nor can there be. It fits into a category that I once coined as, ?precision ambiguity.? Into this category we can place all phrases (1) That are vague, and (2) For which the exact nature of the vagueness can be precisely described. In this specific instance, the ?precisely ambiguous? phrase is ?likely to require.? Many arguments can be put forth, with regard to the intended meaning of this phrase. Few can be effectively refuted. So where does that leave us?
I suggest that we turn our attention to the purpose of 110.26. If you touch 120 volts, and if the current exceeds the ?let go? value, and if your hands therefore refuse to obey the ?let go command? given to them by your brain, one thing that might keep you alive is having the weight of your body (i.e., as it collapses from loss of muscle control) pull your hands away from the circuit. If you don?t have enough clearance, your body won?t be able to fall far enough away. Many of you have had personal experiences related in some way to this process, whereas I (fortunately) have not. But as a design engineer, I will always fight to provide working clearance, even though its need may seem (on paper, at least) questionable. My simple reason is that some electrician might someday be pressured by his or her boss to work something live, even though I thought it should only be worked de-energized.
I now refer the reader back to my initial posing within this topic.
This is another case in which language fails us. There is no clear answer, nor can there be. It fits into a category that I once coined as, ?precision ambiguity.? Into this category we can place all phrases (1) That are vague, and (2) For which the exact nature of the vagueness can be precisely described. In this specific instance, the ?precisely ambiguous? phrase is ?likely to require.? Many arguments can be put forth, with regard to the intended meaning of this phrase. Few can be effectively refuted. So where does that leave us?
I suggest that we turn our attention to the purpose of 110.26. If you touch 120 volts, and if the current exceeds the ?let go? value, and if your hands therefore refuse to obey the ?let go command? given to them by your brain, one thing that might keep you alive is having the weight of your body (i.e., as it collapses from loss of muscle control) pull your hands away from the circuit. If you don?t have enough clearance, your body won?t be able to fall far enough away. Many of you have had personal experiences related in some way to this process, whereas I (fortunately) have not. But as a design engineer, I will always fight to provide working clearance, even though its need may seem (on paper, at least) questionable. My simple reason is that some electrician might someday be pressured by his or her boss to work something live, even though I thought it should only be worked de-energized.
I now refer the reader back to my initial posing within this topic.
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