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UL for Through Wall Outlet Boxes

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ARBY777

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I am seeing an increased use of through wall outlet boxes (i.e., electrical outlet boxes open on both ends) to facilitate back-to-back receptacle installation. I have been looking for UL requirements concerning these boxes and assume they are covered by 514A. Is this correct? Also, I understand that one cannot use these boxes in a firewall application, however, is there a need to have a fire stop rating on it for use in non firewall applications?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
ARBY777 said:
I am seeing an increased use of through wall outlet boxes (i.e., electrical outlet boxes open on both ends) to facilitate back-to-back receptacle installation. I have been looking for UL requirements concerning these boxes and assume they are covered by 514A. Is this correct? Also, I understand that one cannot use these boxes in a firewall application, however, is there a need to have a fire stop rating on it for use in non firewall applications?
I have not been able to locate these on the web and I have never seen one but there are 2 issues that I see with them. Privacy for one-- open on both ends means noise will travel easily between rooms and second would be box fill-- probably not that much of an issue. I am curious as to where the wires enter the box, my guess is in the middle. If you can find a picture I would like to see one. Thanks
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Here is one from Arlington:

FTW1-both.jpg


And the link:

http://www.aifittings.com/whnew67.htm
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
ARBY777 said:
I am seeing an increased use of through wall outlet boxes (i.e., electrical outlet boxes open on both ends) to facilitate back-to-back receptacle installation. I have been looking for UL requirements concerning these boxes and assume they are covered by 514A. Is this correct? Also, I understand that one cannot use these boxes in a firewall application, however, is there a need to have a fire stop rating on it for use in non firewall applications?
There's your answer-- Infinity's link shows the UL-- I copied it
FTW1-full.jpg
 

allenwayne

Senior Member
Those look like snap fasteners for the NM.Great idea, I wouldn`t much worry about sound travel through the box since it is a drywall construction.Also wire fill for 1 or 2 wires in the box is plenty as shown and a 3 rd from the other end would still work.

Been in that situation where spacing required me to add a stud for spacing in one of the rooms.Great link.
 
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