We are in a debate on what should, or should not be used. I was told that we must use a metal face plate for Garage GDO's, yet, another electrician told me that it doesn't matter. Which is correct. Note: It made logical since at one point to use the metal, to protect the wires in the GDO's recepticle-if a fire was to break loose. (located in the ceiling of the garage--does not need GFCI protection).
There is a requirement(although the std. escapes me right now. Joe?) that fire ratings must be maintained in the event of penetrations in fire rated walls(attached garages would apply). This includes disallowing back-to-back penetrations in the same stud cavity, limiting the total area of the wall space allowed for device boxes(100 sq.in.?), and using metal boxes on fire-rated walls. If a metal box is required to maintain fire resistance ratings, a plastic plate seems to diminish its effectiveness.
Re: Metal or plastic Face plate#77632 06/29/0107:08 AM06/29/0107:08 AM
To properly maintain the fire rating of the ceiling, the box should be wrapped with an approved fire pad. If there was a requirement for metal plates, they would be required in all fire corridors, etc. Besides, why have a metal plate when the fire will burn right through the plastic device?
[This message has been edited by electure (edited 06-29-2001).]
Re: Metal or plastic Face plate#77633 06/29/0111:12 AM06/29/0111:12 AM
Section 300-21. Spread of Fire or Products of Combustion
Electrical installations in hollow spaces, vertical shafts, and ventilation or air-handling ducts shall be made so that the possible spread of fire or products of combustion will not be substantially increased.
Openings around electrical penetrations through fire-resistant-rated walls, partitions, floors, or ceilings shall be firestopped using approved methods to maintain the fire resistance rating.
FPN: Directories of electrical construction materials published by qualified testing laboratories contain many listing installation restrictions necessary to maintain the fire-resistive rating of assemblies where penetrations or openings are made.
An example is the 24-in. (610-mm) minimum horizontal separation that usually applies between boxes on opposite sides of the wall.
Assistance in complying with Section 300-21 can be found in these directories and product listings.
Joe Tedesco, NEC Consultant
Re: Metal or plastic Face plate#77634 06/29/0106:01 PM06/29/0106:01 PM