Panel s and Panel covers

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tstern

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I would like to see some changes in way panels and panel covers are constructed by the manufacturer.
The first one is to require them to install a means of wire management inside each side of the panel. This could be done by simply cutting a raised slot to accommodate a ty-wrap(zip tie) thru it, instead of just ty-wraping everything together and still having the wires spring out just in time when the cover clamp crushes them.
Second but not the last, is to put a weight of not more than 40 lbs. on the panel covers. I run a service truck finding myself removing and then trying to replace these 6' & 7' covers alone. 480V arc flash is just a slip away and so is the first 2" of your toes. What would it take to make these in 2 sections?
And last is to get rid of those annoying cover clamps that only work the first time they are used. All they are good for is pinching wires and falling apart after you finally have 2 of them to start holding. What was ever wrong with simply tapping a hole in the front flange and running a bolt thru the the cover into it??

[ January 25, 2005, 07:58 PM: Message edited by: tstern ]
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Re: Panel s and Panel covers

Originally posted by tstern:
The first one is to require them to install a means of wire management inside each side of the panel. This could be done by simply cutting a raised slot to accommodate a ty-wrap(zip tie) thru it, instead of just ty-wraping everything together and still having the wires spring out just in time when the cover clamp crushes them.
I think that (despite normal practices) this raises some derating issues. Putting stipulations and requirements of this nature seem cosmetic in their intent and could require us to use zip-ties. I'm a zip tie fan, but I'm not too warm and fuzzy with requiring them.
Second but not the last, is to put a weight of not more than 40 lbs. on the panel covers. I run a service truck finding myself removing and then trying to replace these 6' & 7' covers alone. 480V arc flash is just a slip away and so is the first 2" of your toes. What would it take to make these in 2 sections?
See 408.55, and similar areas of 408. Panels are going to be large to meet the wire bending space of these codes. Compromising the integrity of a panel to lessen weight is a scary proposition, too. We elect to take on crushed toes and 480 volts, people walking by tripping into a paper panel didn't see it coming. :)
And last is to get rid of those annoying cover clamps that only work the first time they are used. All they are good for is pinching wires and falling apart after you finally have 2 of them to start holding. What was ever wrong with simply tapping a hole in the front flange and running a bolt thru the the cover into it??
I feel like I'd agree with this, but honestly I don't understand what you're saying. :)
 

pierre

Senior Member
Re: Panel s and Panel covers

Not that I disagree with the possibility of having some more creativity in the panel design, but I agree with George that the free market should drive this, not the NEC.

Pierre
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Re: Panel s and Panel covers

Please read the welcome topic.
What you have posted is a "suggestion" not a proposal.

As the other posts have noted this is not a design rather than a safetyu issue and not in the NEC scope.
 

hurk27

Senior Member
Re: Panel s and Panel covers

Ok how about when a panel cover has just the course thread screws to hold the cover on to have a boss behind the screw hole to keep from running the screw into the service cable. Which would be a UL issue but also a safty issue. I have seen a few guys get arc flashed by this one. :eek:

[ January 26, 2005, 12:45 AM: Message edited by: hurk27 ]
 

George Stolz

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Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Re: Panel s and Panel covers

1.) NEC Section/Paragraph: Article 408
2.) Proposal Recommends: [new text]
3.) Proposal: Add 408.5x Panel Covers. Panel covers weighing in excess of 15 lbs shall provide means to support the panel cover during installation or removal independent of the screws that permanently attach the panel cover. The support shall consist of steel rods that protrude through the panel cover when installed, substantial clips at the top of the cover, or both.
4.) Substantiation: Equipment requiring servicing while energized poses a serious safety concern. This requirement would reduce accidents where heavy panel covers are dropped onto busbars of live equipment.

:D

[ January 26, 2005, 07:52 AM: Message edited by: georgestolz ]
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Re: Panel s and Panel covers

Thanks George :D

I would delete the second sentence and let the product standards (NEMA & UL for example) determine the means and methods. Fifteen pounds may also be a bit low but that is fine as a definitive requirement. The CMP or public commentors may suggest a stronger basis for a different value. Tsern started at 40. Maybe he would suggest "Code" text for a mandatory wire management scheme.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Re: Panel s and Panel covers

it seems to me the problem is people servicing the panel while it is hot.

if the worry is the panel door will become energized, require it be made of nonconductive material, which would also tend to reduce the weight.

seriously, i see the intent as desirable but it seems to me to be more along a design issue rather than a safety thing. now if there were a groundswell of demand for such a modification, the manufacturers might well start supplying it.
 
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