Electrical Rm Clearance

[bcorps]

This looks okay to me, but I'd like to get your take on it.



2000-amp 480Y/277V HSMB on concrete pad. Only one exit from room (into another electrical room, not shown). My issue is does the exit have to be out past the clearance to the right, or is it okay as shown? If because it's on the side, and not in front, it must be 2 x 4 feet, and not just 2 x 3.5 ft, we've got enough room for that also. The thing is, I can not move the door any farther to the right, due to what's on the other side. I've got just enough of a niche in the exterior wall for the switchboard, so I'd love to be able to make the most of it.

 

[Rock86]

I think your door location and clearance is okay. Do you have 30" for your clearance width? or is your equipment greater than 30" wide? 110.26(2)

 

[bcorps]

I think your door location and clearance is okay. Do you have 30" for your clearance width? or is your equipment greater than 30" wide? 110.26(2)

It's 76 inches wide. I tried not to show all of the clearances like the panels and transformer, which shouldn't be an issue.

 

[Rock86]

It's 76 inches wide. I tried not to show all of the clearances like the panels and transformer, which shouldn't be an issue.

Oh... I misread it as being 2' x 42"... I didnt see the break for each panel at first.

 

[Strathead]

It's 76 inches wide. I tried not to show all of the clearances like the panels and transformer, which shouldn't be an issue.

Well, if you are looking for an honest opinion, as an installer I would be immediately be confused by what you are trying to convey. What does the 2 mean in 2 x 42. It the panel is 72" wide then why is the 42" depth longer than the 72" width? Either show all of the clearances or just a simple note to comply with NEC 110.26. Without having a scale, I would be more concerned with the ground to ground clearance of the transformer to the DPNL than the front of the HMSB.

 

[bcorps]

Well, if you are looking for an honest opinion, as an installer I would be immediately be confused by what you are trying to convey. What does the 2 mean in 2 x 42. It the panel is 72" wide then why is the 42" depth longer than the 72" width? Either show all of the clearances or just a simple note to comply with NEC 110.26. Without having a scale, I would be more concerned with the ground to ground clearance of the transformer to the DPNL than the front of the HMSB.

The 2 x 42 is a reference to twice the required clearance depth in front due to only having one exit. I'm sorry if my explanation was lacking.

 

[augie47]

Do you have the required distance in front of DPNL to the transformer ?

 

[bcorps]

Do you have the required distance in front of DPNL to the transformer ?

It's 36 inches, being a 208V panel. Lots of clearance in that area. My issue was the location of the door, and whether it could be anywhere, so long as I have double the clearance in from of the switchboard.

 

[Strathead]

It's 36 inches, being a 208V panel. Lots of clearance in that area. My issue was the location of the door, and whether it could be anywhere, so long as I have double the clearance in from of the switchboard.

The door , even if it swung in to the space doesn't count, even though it maybe should. Having a panel in a small room/closet behind the door is not uncommon.

 

[bcorps]

The door , even if it swung in to the space doesn't count, even though it maybe should. Having a panel in a small room/closet behind the door is not uncommon.

I suspected this, but since it isn't something I would typically do, it just felt weird. I'm kind of constrained by existing conditions here, where I would generally put the exit opposite the switchboard or have two doors on the sides.

 

[infinity]

The 2 x 42 is a reference to twice the required clearance depth in front due to only having one exit. I'm sorry if my explanation was lacking.

Just curious as to why this is 42"? Isn't this Condition 1 (36") in Table 110.26(A)(1)?

 

[bcorps]

Condition 2. Concrete walls are considered "grounded" materials.

 

[infinity]

Condition 2. Concrete walls are considered "grounded" materials.

Ah, I thought that it was drywall.

 

[WA_Sparky]

Condition 2. Concrete walls are considered "grounded" materials.

So in order for this to work you would need twice the working clearance in front or 7' from the front of switch board (condition 2 = 3'6") to avoid a second exit? Correct?

 

[Carultch]

Condition 2. Concrete walls are considered "grounded" materials.

The transformer housing would also make this Condition 2 at a minimum, since most (if not all) transformers have metal housing. If it were the front of the transformer, such that the transformer and HMSB share a common aisle, I could see a case to be made that it is condition 3.