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Joined: Jan 2005
Posts: 5,445 Likes: 3
Cat Servant Member
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The problem with having rules is that rules are static, and have no flexibility for particular circumstances. Safety? The very idea of 'safety' is a balancing of competing risks and managing losses.
The NEC recognizes this - as well as its' own legal limits - by referring matters back to the judgement of the AHJ. In the end, it's the responsibility of the AHJ, regardless of what some committee put down in a privately owned 'model' code.
The matter at hand is one classic such example. I am surprised that none of out 'urban' folks have yet posted a picture of such a situation as this thread describes. Let's imagine a fairly common arrangement:
A commercial panelboard placed outside, opening into a 'common' area, such as a drive or an alleyway, right on the property line. On either side of the panelboard is a bollard, with removable horizontal members spanning the distance between the bollards. Perhaps these pieces are held in place with bolts, or even padlocks.
Now, you have to ask: what's more likely? A catastrophic fire, and earthquake, or an errant delivery truck? Do you want to try to open an arcing cabinet whose doors have been pushed in by a few tons of Detroit iron? Do we want lesser damage to be left untended, letting weather and critters into the innards, as well as making the cabinet difficult to open?
I'd say a few pounds of structural iron in front of the gear is a very good trade-off. So what if you need tools and a key to make the gear accessible?
Remember - even if the gear is not obstructed in any manner, the NEC allows the mains to be locked "on" with the strongest chain and stoutest locks you can find. Code also allows this gear to be inside a locked room.
You really want a disconnect? Then mount a 'shunt trip' on the wall- but protect the gear!
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Joined: Apr 2002
Posts: 7,381 Likes: 7
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Electrical equipment that may be subject to physical damage requires protection. Metering equipment, CTs & MOCP also have to comply with our POCOs requirements; which are for the most part equal to NEC.
'Usual' protection consists of multiple bollards (4"-6" RGC) w/concrete, spaced to allow full frontal access, and required clearances. Rationalization is that a vehicle cannot fit thru a +/- 3' space between the bollards.
Equipment within active warehouses has either bollards, or 'guardrails' 4'6" from the face of the equipment. The bollard spacing is +/-2'6". All are designed by an Arch or Engineer. The guardrail type are accessed from openings at either end.
Reno:
You asked"I am surprised that none of out 'urban' folks have yet posted a picture of such a situation as this thread describes"
I'll try to get some pics this coming week, time permitting.
John
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Joined: Nov 2002
Posts: 244
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Reno,your post exemplifies what I was originally getting at as far as inspector preference. Great example of how people/inspectors can view things from different angles.
I was reading a thread in another forum on panels behind door swings. Some of the inspectors liked the idea of the panel behind the door because it somewhat guaranteed that the space wouldn't be blocked by storage items. Others where totally against the idea.
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Joined: Oct 2000
Posts: 2,723 Likes: 1
Broom Pusher and Member
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Why not 2 bollards straddling the panel, 30+" apart. That would offer better protection and still keep the front of the equipment clear.
Greg's quoted statement would also be my preferred option. Placement of "Bollards" should allow for access, without becoming an issue for Live Testing. If the Service Equipment is a typical Safety Socket, Bollard placement at 15" left/right of the Panel's Centerline would allow clearance and still protect from aggressive Forklifts. wewire2; Is this Project the SOW 300 Bldg.? If so, there may be Design Specifics in the Project Manual which should be reviewed; and, if needed, submit an RFI. --Scott (EE)
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
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Joined: Nov 2002
Posts: 244
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Yo Scott! Still haven't heard a word about that project since it got mothballed. Landed a large commercial TI so things are looking better over here.
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Joined: Apr 2002
Posts: 7,381 Likes: 7
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Scott:
I guess we agree on what I said as being compliant and providing protection?
John
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Joined: Feb 2002
Posts: 2,233
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It seems to me that anything can go as long as everything is normal. However once something bad happens, (Fire, someone gets hurt, etc) then everyone is at fault and to blame. Right down to the people who manufacture the bollard, and even the person who delivered it to the job site. They will all get sued and dragged into court.
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Joined: Oct 2000
Posts: 2,723 Likes: 1
Broom Pusher and Member
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John;
I guess we agree on what I said as being compliant and providing protection?
Heck Ya!!!  --Scott (EE)
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
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Joined: Apr 2002
Posts: 7,381 Likes: 7
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Scott:
Thanks!!! Now I feel better!!
John
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HCE727
Delaware County, PA, USA
Posts: 187
Joined: November 2005
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