Electrical Panel Clearances

[ponycar17]

I've recently been asked to document the specific regulations concerning temporary storage of items in front of electrical panels. I realize that by NEC 2005 Article 110.26 Table 110.26(A)(1), that our 480 VAC control cabinet must have a minimum of 42" of working space in front of it. The problem I have is that this seems very vague with respect to closed cabinets. OSHA regulations seem to blur the NEC requirements to mean that the cabinet has to be "easily accessible." Does this mean that temporary storage, such as that on a cart, is acceptable?

Is there a specific NFPA, OSHA or even NEC regulation that covers access to control cabinets, even when the item being stored in front is readily moved?

Thanks for the help in advance!...

 

[BJC]

Open or closed the clearance is 42". Easily accessable means you can get to it, no ladders, no climbing under or over stuff, no rmoving ceiling panels etc. Generally it means you can walk to it.
Storage is storage - on a cart, in a carton, etc.
The standard practice is to paint the required clearance in yellow on the floor. Nothing goes in that space and you can walk to it.

 

[ponycar17]

Any idea which code says "open or closed?"... That's the real problem. I understand that 42" should be the clearance, but getting other non-technical (read management) folks to understand that without specific references is another matter entirely.

Thanks

 

[davidbeach]

The code does not make any distinction, the required clearance is the required clearance. There are no conditions listed for which the required clearance is not required.

 

[dpc]

You can call your state electrical inspector and ask a hypothetical question. You will almost certainly get the same answer you are getting here and that will be the end of discussion.

 

[ponycar17]

NEC 2005 Article 110.26 Table 110.26(A)(1)states a voltage level and 3 levels of exposure. 1) Exposed energized parts adjacent to an insulated area 2) Exposed energized parts adjacent to a grounded area and 3) Exposed energized parts adjacent to other exposed and energized parts. I'm not following how that tells you a closed panel needs a clearance of 42 inches. I understand what you guys are saying, and agree with you, however it's hard to convince non-technical types who have more leverage than you... I need something in writing.

 

[BJC]

You arn't going to find it in writing.
If the panel is close I guess you could assume it doen't need any clearance.
The purpose of the code seems intuitively obvious to me. Something happens ( some light go out, a water heater pops a circuit breaker etc) an electrican goes down and opens the panel to see what happened. But wait he can't, he's got to move a bunch of crap. What if it's an arcing fault feeding a fire? What if it's someone caught in a machine, or someone with a live wire laying on them etc. It could also be the person opening the panel if they decide in am emergency to open the panel with only 12 or so inches of clearance.
In short the question of open vs closed clearance is to dumb to get an answer in writing, a laugh is a good probability.
If your management won't accept the fact that the clearance is open or shut, write a letter to them clearly stating what is needed, that you strongly object and that you are requesting an outside review by sending a copy of the letter to the local AHJ. If you get fired it may be a good career move.

 

[stevenal]

The table is not a standalone requirement, you must look at the referencing text. 110.16(A)(1) is clear: "Distances shall be measured from the exposed live parts or from the enclosure or opening if the live parts are enclosed."

 

[waross]

In the Canadian code, there is a table giving clearances from energized equipment. Another chapter deals with working space around electrical equipment. In Canada this is the rule that would control the clear space in front of a normal breaker panel. I don't have a copy of the NEC with me, but I am sure that the US regulations are similar.
respectfully

 

[ponycar17]

From BJC,
"If your management won't accept the fact that the clearance is open or shut, write a letter to them clearly stating what is needed, that you strongly object and that you are requesting an outside review by sending a copy of the letter to the local AHJ. If you get fired it may be a good career move. "

Believe me, I've thought the same thing on E-stop and other safety requirements recently... It's rather hard to cope in an environment where there's low turnover, and the average employee has 30 years experience within the same company (and likely the only company they've ever worked for)... 1970s logic for safety is commonplace... It's going to take a long time getting used to this culture vs. my previous workplaces...

 

[rob46]

Article 110.26.A.(1)of the 2004 California Electrical Code clearly states "Distances shall be measured ...from the enclosure...".

 

[ponycar17]

rob46, that's what NEC 2005 says, yes... However, it says "distances shall be measured ...from the enclosure...", but the table specifying distance doesn't cover distance from a closed and grounded panel door; only exposed and energized parts... So, therein lies my dilemma. My thoughts are that the "distance from the enclosure comment" can be interpreted as only applicable when the exposed and energized parts are present (given the table's definition of clearance requirements)... Our safety guy says that OSHA says that electrical panels "must be kept clear" for 36", or so he thinks... If that's so, that's a start...

 

[davidbeach]

Look, if you don't believe all of us, why don't you just call in the local electrical inspector? The way the rule is often explained is take a refrigerator box, 30" wide, 78" tall and 36", 42", or 48" deep, and slide it up to the panel. Nothing is allowed in that box except that there may be minor electrical appurtenances that project slightly into the box below the panel. Nothing is allowed in the box. Doors open, doors closed, nothing is allowed in the box. While the box is sitting there, outline it on the floor with clearance tape, nothing is allowed in the space marked by the tape. Nothing. People may move through, but nothing may be placed there.

 

[ponycar17]

Oh, it's not that I don't believe you, but I'm playing devil's advocate... Our rather non-technical production group is not going to take anything seriously unless it's in writing. Or, that's how I've taken their reaction thus far...

 

[BJC]

"Oh, it's not that I don't believe you, but I'm playing devil's advocate... "
So stop playing (At least here). Tell the production group they are in charge of production and your in charge of electrical stuff. Do you need a cahones transplant? If your going to let yourself be pushed around then the future is going to be hell. You have the code, common sense, opions from this group, your own training and you can get a local AHJ to back you up. If thats not enough consider a career in investment banking or something.

 

[dpc]

I think you state electrical inspector would be willing to write you a letter giving his/her interpretation. That would be fairly definitive.

There's nothing to be gained from parsing the NEC looking for inconsistencies and loopholes. There are plenty to be found, but that is why the final interpretation is left to the local inspector.

 

[stevenal]

I believe the working space conditions refer to the equipment as worked, hence the title. Open the front of a dead front piece of equipment with no other access and you have condition 1, 2 or 3 depending on what is behind you. Get clearance from the table, then measure it from the opening or enclosure per the text. Note that (a) only speaks of the back and sides assuming you already have your clearance to the front.

Also note that the space must be kept clear even when no work is being performed. My "as worked" statement is only for figuring out which column to enter the table with.

 

[ponycar17]

"So stop playing (At least here). Tell the production group they are in charge of production and your in charge of electrical stuff. Do you need a cahones transplant? If your going to let yourself be pushed around then the future is going to be hell. You have the code, common sense, opions from this group, your own training and you can get a local AHJ to back you up. If thats not enough consider a career in investment banking or something. "

I appreciate your *constructive* criticism... The truth is, we're trying to build a case to take to plant management about this issue, and with several people already telling the violating party that they're doing something wrong to no avail, I came here to get a reference to an actual code... I have the cahones, no problem, but it does little good in an environment where production is everything...

 

[davidbeach]

How much production will be accomplished when OHSA shuts the place down for violating the required panel clearance zones?

 

[jraef]

Interesting dilemma really, it seems to me to be more psychological than technical in that they feel that ALL real estate in their building should be usable for whatever they want unless forced not to by specific printed rules rather than common sense. I have been in this situation several times, but fortunately for me as a consultant rather than an employee most of the time. So I could make my report and walk away when things got stupid like this (still sticks in my craw however just by remembering now).

How about this tactic;
From the sounds of it, they are not going to be able to accurately interpret the complexities of NFPA 70E (Arc Flash Safety), which not only can be interpreted to require up to 48" clearance on 480V gear, but also require a label on the outside of the box saying that anyone coming near must be dressed in a specific matter (PPE requirements) blah blah blah. I'm not saying here that this piece of equipment will require all that much, in fact is probably won't, but the complexities of Article 409 are too much even for some experienced engineers, let alone "non-technical types" with their heads up their ...

So tell them that as long as the person pushing that cart into the room or going in to remove it will need to wear a long sleeve cotton shirt, cotton underwear and fire resistant pants, they can do whatever they think is acceptable. Then show them an NFPA70E sticker example like this:

By the way, if it helps, NFPA 70E rules are very clear about whether the box is open or closed and will require at least 3'6" of clearance from any exposed live parts (implying Open) but adds "approach boundary" and "restricted space" requirements as well. Again, this applies to exposed live electrical equipment, but you can possibly exploit their likely ignorance or confusion by overloading them with this kind of info. For sure, there are scam artists out there now who are capitalizing on this to extract money from the uninformed, all you want is for them to not be stupid about storing stuff too close to electrical cabinets.

http://www.cdc.gov/elcosh/docs/d0500/d000580/d000580.html