(yet another) Clarification on enclosures (110.26(A)(1))

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Hamberg

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Assuming there is 56" in front of the existing subpanel (entry door closed), can you add an additional sub directly next to the existing (existing may need to be moved over for spacing)? All doors would have a min of 90° opening.



Enclosure.jpg
 
Y

yesterlectric

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PA
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The rule is you need 30" or the width of the piece or pieces of equipment (whichever is greater) and the working space provided by that width needs to extend out per the depth shown in table 110.26A1. Occasionally we get someone saying if two panelboards are side by side, that the 30" width must be able to be maintained around panel "A" when the door to access the breakers at panel "B" is opened. This is not the consensus however but occasionally is something people make an unneeded issue about.
 
infinity

infinity

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Technically the two panels would need to be the same depth when mounted next to each other.
 
infinity

infinity

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Since the two panels occupy the same working space the front edges of the panels must be aligned with each other.
 
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Hamberg

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Just read & reread 110 and am not seeing the reference to two adjacent "live parts" having to be the same depth?

One thing that did strike me as peculiar was two panels facing each other (condition 3) needed the 3ft spacing but no reference to two panels being perpendicular (like mine) needing that separation (side to side) - just the 3ft in front.
 
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wwhitney

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Hamberg said:
Just read & reread 110 and am not seeing the reference to two adjacent "live parts" having to be the same depth?
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Say your two panels are different depths (a non-negligible amount). Since the 30" width for each panel has to overlap the other panel left-right (given your available space), the panel that sticks out farther would be in the working space of the other panel.

110.26(A)(3) does have an allowance for other associated equipment "located above or below the electrical equipment" to stick out up to 6" into the working space. But since the panels are side by side, a strict reading would not allow one panel to stick out into the other's working space.

However, that does mean you could vertically stack two panels that are different depths.

Cheers, Wayne
 
infinity

infinity

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Wayne's explanation is exactly my point. You cannot use the 6" exception because the panels are side by side. IMO 1/8" difference is nothing to even bother considering.
 
infinity

infinity

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wwhitney said:
Do you see a substantive safety difference (between side by side vs vertically stacked) that would explain that limitation in the allowance, or is it just sloppy wording?

Cheers, Wayne
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I think that the wording is correct. If you sandwiched a 14.5" wide panel between two 10" wireways it would be possible to contact the wireway while working in the panel.
 
LarryFine

LarryFine

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infinity said:
I think that the wording is correct. If you sandwiched a 14.5" wide panel between two 10" wireways it would be possible to contact the wireway while working in the panel.
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Wouldn't that also apply to, for example, a panel hidden behind a hinged door in a wall, even if the space was as shallow as possible? The door opening would have to be at least 30" wide, too, right?
 
infinity

infinity

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LarryFine said:
Wouldn't that also apply to, for example, a panel hidden behind a hinged door in a wall, even if the space was as shallow as possible? The door opening would have to be at least 30" wide, too, right?
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That's correct, it's something that is often overlooked with those types of installations. For me I would rather be leaning against wood or drywall then a grounded metal object when working in a live panel.
 
C

Carultch

Senior Member
Location
Massachusetts
Hamberg said:
Just read & reread 110 and am not seeing the reference to two adjacent "live parts" having to be the same depth?

One thing that did strike me as peculiar was two panels facing each other (condition 3) needed the 3ft spacing but no reference to two panels being perpendicular (like mine) needing that separation (side to side) - just the 3ft in front.
Click to expand...
The depth of the working space is a function of the voltage and the surface behind you while you work on the equipment. The reason why this is, is that instinct is to move backward, away from the live circuit if you get shocked, rather than to the side. It is safest if the surface behind you is insulated, and most dangerous if there is other equipment behind you. Electrically inactive metal behind you, like a chain link fence, or the back/sides of other equipment, would be intermediate.

Working space requirements for two pieces of equipment on perpendicular walls are independent of each other. It is only working space for equipment on opposite walls, sharing a common aisle, that influences the required working space, such that it is condition 3, instead of one of the two previous conditions.
 
T

Tulsa Electrician

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Tulsa
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Electrician
If the 1/8" bothers you. Through a washer or two behind the thinner panel. Then there flush with each other. I have seen this done when a panel board was set next to an load center. They just pulled the load center forward.
 
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