18" clearance in closets???

[Anonymous]

Posted by: Baron-2
Posted: Wed Sep 11, 2002 11:18 pm

What is the NEC logic for requiring clearance of 18" (sides & back) and 6" (from shelving) on fluorescent lighting in closets? I can't imagine it has anything to do with heat generated by the light fixture. Any idea? I just installed these in every closet in my house and I doubt any have 18" clearance on the sides! Please tell me I don't have to pull them out.

[Anonymous]

Posted by: Donnie
Posted: Thu Sep 12, 2002 10:07 am

2002 NEC art.410.8 (D)location (2)reads-surface-mounted fluorescent luminaires(fixtures) installed on the wall above the door or on the ceiling provided there is a minimum clearance of 6" between the fixture and thenearest point of storage space shall be permitted.
I don't any requirements for 18" from the ends.As long as there is 6" of clearance from the shelf(shelves) you will be OK.
Where did you get the 18" reference from??

[Anonymous]

Posted by: Wgoodrich
Posted: Thu Sep 12, 2002 2:30 pm

Baron-2 the side walls distance requirement does apply to all light fixtures 24" from incandescent light fixtures with a closed lens or 18" from the edge of the flourescent light fixture and 18" from the edge of the trim of an inscandescent light fixture. You may seek a ruling forgiving a part of the rule by your local electrical inspector due to hardship or other reason you can provide to him or her. The inspector is the Authority Having Jurisdiction and is the only person that can use 90.4 suspending a rule of the NEC. Inspectors are reluctant to use 90.4 if they are a reliable inspector. It is his or her call. You might read my attempt to help Donnie find where the rule exists concerning the back and side wall clearance requirements, it should help you advance your knowledge also.

Donnie,
I think that you started to late in the rules of 410.8 try looking at the beginning of 410.8, remember all of 410.8 applies directly to lights in clothes closets. The definition of a clothes closet storage space declares both the back and side walls applying to the designated storage area of a clothes closet that the clearance must be maintained from all light fixtures in the clothes closets. The rest of Article 410.8 depicts the distance from that storage are for each type light fixture installed in a clothes closet but the designated storage area is always the same distance from back and side walls to be designated as the storage area of a clothes closet regardless whether there is a clothes rod or storage shelf installed in that closet or not. Below is a copied section of the definition declaring the designated storage area in a clothes closet found in Article 410.8.A;

COPIED SECTION OF 2002 NEC RULE; 410.8.A
Storage Space. The volume bounded by the sides and back closet walls and planes extending from the closet floor vertically to a height of 1.8 m (6 ft) or the highest clothes-hanging rod and parallel to the walls at a horizontal distance of 600 mm (24 in.) from the sides and back of the closet walls, respectively, and continuing vertically to the closet ceiling parallel to the walls at a horizontal distance of 300 mm (12 in.) or the width of the shelf, whichever is greater; for a closet that permits access to both sides of a hanging rod, this space includes the volume below the highest rod extending 300 mm (12 in.) on either side of the rod on a plane horizontal to the floor extending the entire length of the rod.

FPN:See Figure 410.8.

COPIED SECTION OF 2002 NEC HANDBOOK COMMENTARY;
410.8.A
The 24-in. rule is intended to cover the clothes-hanging space, even if no clothes-hanging rod is installed. If a clothes-hanging rod is installed, the space extends from the floor to the top of the highest rod. If no clothes-hanging rod is installed, the space extends from the floor to a height of 6 ft.
In addition to the space in which clothing will be hung from the closet pole or rod, this requirement also establishes a 12-in. wide shelf space to cover those installations where shelving is not in place at the time of fixture installation. If shelving is installed and the shelves are wider than 12 in., the greater width must be applied in establishing this space.
The storage space for closets that permit access to both sides of the clothes-hanging rod is based on a horizontal plane extending 12 in. from both sides of the rod, from the rod down to the floor. This equates to the 24-in. space required for the closet rod where there is only one direction of access.

Comment by Wg

If you check the NEC 99 rule is very similar to the 2002 version also with same Code number as reference in both NEC version.

Also if you have a Code book to look at there is a drawing that is a part of the rule showing what the written text in the rule is saying. This drawing is a part of the NEC rule and enforcable as a part of that rule. This drawing may help you see where the back and side wall statement is coming from.

Hope this helps

Wg

[Anonymous]

Posted by: Baron-2
Posted: Fri Sep 13, 2002 8:32 am

Well, I was hoping Donnie was right, but I understand what you're saying, wgoodrich. I'll see what I can do to avoid the changes.

Most codes seem to make sense in that not following them could cause fire, injury, or other damage, but this one still perplexes me. What prompted the NEC gods to make this rule in the first place? Is there a hazard presented by fluorescent light fixtures being 17" from a closet side wall, or even 1" for that matter? It seems illogical to me.

Thanks for your feedback!

[Anonymous]

Posted by: Wgoodrich
Posted: Sat Sep 14, 2002 12:01 pm

Over the nation there is a long history of flourescent ballast overheating. While there is a required themo in the ballast to shut it down eventually in an attempt to limit fires the ballast can get much hotter than a normal light bulb. However this hot ballast is within the casing that then must heat up enough to ignite easily ignitable material such as wedding dress lace etc. This outer casing seems to be the reason for the reduction from 24" to 18" but the acknowledgement of heat due to overheating ballast before the thermo cuts out seems to be the concern for the 18" minimum distance requirement. This is my understanding of the whys and therefores of the reduced distance for flourescents fixtures versus incandescent fixtures with a globe. Attempt to reduce fires appearing across the nation is the reason for the minimum clearances.

Hope this helps

Wg