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Box Requirement for Adding Light Fixture to Masonry Garage

Box Requirement for Adding Light Fixture to Masonry Garage

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  #1  
Old 09-04-13, 04:42 PM
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Box Requirement for Adding Light Fixture to Masonry Garage

My parent's detached garage is in a historic section of town, so we're talking homes in the 75-90 year old range, probably. Awhile back an electrician came a drilled a simple hole through the stucco-covered block walls for exterior lights to be installed on the garage. Can't remember why the project was never finished, but I'd like to finish it for them.

My question is what the most proper method would be for adding boxes on which to secure the fixture. My gut says I need to cut into the masonry for an octagon box, but would a pan box, surface mounted be acceptable? I suppose I'd have to check the cubic inch fill amount for the wires, but are pan boxes, in general, an ok method?

I'm not opposed to cutting into the masonry, though it would be much more work. But I notice that the octagon boxes with NM clamps seem to be expecting the wires to feed in from the side (top/bottom). However the previously drilled hole in the masonry means bringing the wire in the center hole on the back of such a box. I assume the only way to to this properly would be to run conduit through the thickness of the block wall and secure to the box? Is that right? If so, then is no clamp required where the wires enter the box?

Several questions. I've done a good deal of re-wiring my own house, but none of that has been masonry, so I'm not experienced in retrofitting something into existing masonry. I want to make sure it's at or above code, including requirement for conduit, etc.

Any assistance is much appreciated.
 
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  #2  
Old 09-04-13, 05:18 PM
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An octagon box can be used with the cable into the back. A conduit sleeve can be used but is not necessary. A pancake box might work under the fixture canopy. There could only be one 14-2 cable, any more would need a deeper box.
 
  #3  
Old 09-04-13, 05:28 PM
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is no clamp required where the wires enter the box?
A clamp is required. Strip the jacket off the cable where you can still reach with a screwdriver (in front of the wall). Tighten the clamp onto the remaining cable jacket. Remove the locknut from the clamp and the KO from the box. feed the cable with the clamp on it into the KO in the box and install the locknut. Then mount - secure the box.
 
  #4  
Old 09-04-13, 07:34 PM
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Thanks for the replies so far - that's helpful! As a follow-up, is conduit needed through the masonry wall?
 
  #5  
Old 09-06-13, 05:19 PM
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Not unless you think the masonry will somehow abrade the cable. IOW, no.
 
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