Panel Boards Opposite Across an Isle

[stretched2thin]

If two panel boards are located across an isle from each other, what is the total distance required between the face of the two panels? (<600 V, No live parts on either side of panel) If I'm interpretting NEC 110.26(A)(1)correctly, I think it should be 3 ft. for each panel (6 ft. total). Or should it be 3 ft. total?

Panel 1
|
---------========-----------
^
I |
S |
L Total Distance
E |
|
v
---------========-----------
|
Panel 2

 

[DanDel]

I would interpret the requirement as 3 ft total, since Table 110.26(A)(1), Condition 1, says: &quot;..or exposed live parts on both sides effectively guarded by suitable wood or other insulating materials.&quot;; and Art. 110.26(A)(1) says: &quot;Distances shall be measured from the exposed live parts or from the enclosure or opening if the live parts are enclosed.&quot;

 

[pablo02]

Ah, but these are electrical panels and should be grounded: if the voltage is over 150v, the distance should be 3½ ft (condition 2)... and this assumes that both panels won't be worked on at the same time (requires 4 ft - condition 3)... (ref same table: Table 110.26(A)(1)...) -- if this aisle is also used as an exit way, you may need to check any other applicable codes

 

[stretched2thin]

Doesn't Condition 3 assume that the building is an existing installation. If this building is about to be built, would Condition 3 still apply?

 

[pablo02]

I'm not an expert on interpreting the code -- but, I think just the opposite applies -- that condition 3 does apply to new construction, condition 2 may be used on existing buildings if provisions under section 110.26 (A) (1) (c) are met...

 

[buzzp]

Not sure why my reply did not post yesterdat.
I would classify your application as condition three if both panels will have live parts exposed at any time (of which I doubt). So with 150-600V to ground, your clearance required would be 4 feet. If only one panel will have live parts exposed at any time then one panel will effectively be grounded and the other panel will have exposed parts so condition 2 would apply and the clearance should be 3.5 feet. Thats how I would interpret this section of the NEC. Keep in mind that I am no expert either but feel comfortable with my statements above.

 

[dpc]

There is nothing to prevent the exposure of live parts on both sides - this happens quite commonly during maintenance and when people forget to put the covers back on.

This is clearly a &quot;Condition 3&quot; in the NEC and the required distance is 3.5 feet if 150 to ground or less, or 4 feet if more than 150 volts to ground. In fact, this is exactly the situation that defines Condition 3 in the NEC handbook published by NFPA. (Well, OK, they show a two switcboards facing each other, not panelboards - but same situation.)

This situation has always been interpreted as Condition 3 by every engineer and inspector that I known. And that is several inspectors too many.

This one is pretty clear cut, at least in my experience.

 

[peebee]

I agree with dpc. 3' if 0-150, or 4' for 150-600 volts.

You definitely don't need 6' as you originally thought.

 

[peebee]

Oops, I also agree with pablo02, you can reduce to 3.5' if this is an existing installation.

By the way, just what isle are the panels located on? ;0)

 

[stretched2thin]

Gilligan's Aisle. (Sorry. I can't believe I did that.)

 

[profilebusbar]

I agree with DPC &quot;Condition 3&quot; in the NEC , required distance is 3.5 feet if 150 to ground or less, or 4 feet if more than 150 volts to ground

 

[RonShap]

Not to muddy the waters too much, but who is to say that these panels require examination, adjustment, servicing or maintenance while energized? Some might argue that there is 0' working space requirement from Table 110.26(A)(1), as none of the conditions will be accurate.
Couldn't you measure volts and amps by turning power off, open the cover, applying the meter, close the cover with the leads run out of the panel door, then re energize the panel?
I'm just raising some possibilities. Of course the inevitable thermo scan will require examination while energized. Other thoughts?

 

[advidana]

If the panels has have removable cover facing each other then condition 3 applies. I check prior nec's, it has been that way since NEC1978. Before that is was different lengths but still condition 3.

 

[buzzp]

One would not be wrong in assuming condition two regardless of what has been done in the past. Of course, your hard nose inspector may want to stick with &quot;the way things have always been done&quot;. You can argue that both panels will not be worked on at the same time so the enclosure of one is at ground potential. Whatever you decide, your inspector will tell you the proper way (what he feels like) when it is to late. To be safe, four feet.

 

[advidana]

another issue is where is 3 foot isles allow? My understanding UBC requires wider isles than that.

 

[stretched2thin]

We plan to use 4'-6&quot; as our aisle width. So, according to all posts (and contrary to my original assumption), we should be ok. Thank you all for your opinions.