Concrete Block - Outdoor sconce light.

[madosta]

If I wanted to mount something like this to a block wall exterior how can I go about it:

I could put junction boxes surface mounted then sheath NM or THWN outside to them, but I don't want the ugly junction boxes.

I could drill a hole for the wire and mount the lights directly to the block.

Can I use BX armored cable or should it be wet location since it will be running between the block, up through my ledger inside to a j-box with romex.

 

[Aceman]

Cut a single gang masonry box into the block.

A masonry wheel in an angle grinder is how I've seen the brickies do it. Chisel the corners out.

 

[madosta]

OK,

I think if I get something like this and set it in, it should work. http://www.garvinindustries.com/Electrical-Junction-Boxes/Masonry-Boxes/3-1-2-Deep/TB-135

What about the wire to it? Since it will be in a block wall void from the top of the block and I don't know about NM? Armored cable?

 

[slickgt1]

Stay away from square boxes for light fixtures. Not all will cover the edges of the square box.

Get something like this.
http://www.garvinindustries.com/Electrical-Junction-Boxes/3-1-2-Octagon-Boxes/1-1-2-Deep/24151-1-2

Take grinder, or if you are scared of grinders, do what one of my noob workers does. Take a mason drill, and drill the perimeter outline of that box. Chisel out the inside. But that is such a pain in the ***. Honestly, 6 cuts with a grinder take a minute.

Recess that box in the block, doesn't matter if deeper than necessary, the mounts on those lights account for that. Silicone the gaps. Mount light, done. Remember, hole for the electrical is bigger than the hole on the box. You need to account for the connector.

 

[madosta]

Stay away from square boxes for light fixtures. Not all will cover the edges of the square box.

Get something like this.
http://www.garvinindustries.com/Electrical-Junction-Boxes/3-1-2-Octagon-Boxes/1-1-2-Deep/24151-1-2

Take grinder, or if you are scared of grinders, do what one of my noob workers does. Take a mason drill, and drill the perimeter outline of that box. Chisel out the inside. But that is such a pain in the ***. Honestly, 6 cuts with a grinder take a minute.

Recess that box in the block, doesn't matter if deeper than necessary, the mounts on those lights account for that. Silicone the gaps. Mount light, done. Remember, hole for the electrical is bigger than the hole on the box. You need to account for the connector.

Ok, that's what I was looking for!

Have a grinder and a wheel for it, so not worried about that.

How does the box stay in? Mortar? I would be happier with a solid box mount. Or are you saying to use silicone to hold it until the light also holds it?

Also still need to figure out the "code" wire to use.

 

[slickgt1]

Ok, that's what I was looking for!

Have a grinder and a wheel for it, so not worried about that.

How does the box stay in? Mortar? I would be happier with a solid box mount. Or are you saying to use silicone to hold it until the light also holds it?

Also still need to figure out the "code" wire to use.

No. Box has holes in it for securing. Drill two into the block, put in some plastic anchors, and screw in place. I usually throw in a dab of PL premium, because I just love the stuff. Silicone is to prevent air/water intrusion.

 

[slickgt1]

Forgot to add, I doubt any sconce will need more than a 14ga wire. 12-2 Bx is common here, so I just use that. It's a bit thicker, but not much diff in price.

 

[madosta]

Ok, I think I'm going to do a straight shot inside surface mount jbox with 1/2" emt and run THWN to a recessed box outside.

Thanks!

 

[slickgt1]

Ok, I think I'm going to do a straight shot inside surface mount jbox with 1/2" emt and run THWN to a recessed box outside.

Thanks!

Good call on the emt, but not sure if that is overkill considering it is inside the block. I also don't like surface mount boxes because all painting, and whatever you do to those walls have to be accounted for that box. But I am not sure of your interior layout, so you might be going at it the right way. Still, make sure you secure the outside box with screws. You don't want to depend on the emt to hold your light forever.

 

[Zeke]

If you cut into the cavity of a block wall, I don't see how anchors can be used. I just did this yesterday and I put fast set epoxy around the edges for securing it and water proofing it. The block is too thick for an old work retrofit box. I think one of those fiber boxes has the best chance in a block wall. You may have to cut off any nailing brackets if you can't find a simple smooth box. That's what I did as I didn't want to use a handy box.

 

[JakeKohl]

Forgot to add, I doubt any sconce will need more than a 14ga wire. 12-2 Bx is common here, so I just use that. It's a bit thicker, but not much diff in price.

Wire size depends on your circuit protection. If the light is tying into a 20amp circuit, use a minimum of 12ga. If it is on a 15amp circuit, use a minimium of 14ga. It is a no-no to mix different thickness wires on the same circuit.

 

[madosta]

If you cut into the cavity of a block wall, I don't see how anchors can be used. I just did this yesterday and I put fast set epoxy around the edges for securing it and water proofing it. The block is too thick for an old work retrofit box. I think one of those fiber boxes has the best chance in a block wall. You may have to cut off any nailing brackets if you can't find a simple smooth box. That's what I did as I didn't want to use a handy box.

This is what I was wondering as well. Where do these screws go, because they cant go into the back because there is a void, and the side would just be difficult to get into the edge of the cut block.

I could see if there were ears that prevented the box from sinking into the block void, but I don't see any masonry boxes like that with a quick search.

 

[slickgt1]

Wire size depends on your circuit protection. If the light is tying into a 20amp circuit, use a minimum of 12ga. If it is on a 15amp circuit, use a minimium of 14ga. It is a no-no to mix different thickness wires on the same circuit.

Did I say that. Nope.

 

[slickgt1]

This is what I was wondering as well. Where do these screws go, because they cant go into the back because there is a void, and the side would just be difficult to get into the edge of the cut block.

I could see if there were ears that prevented the box from sinking into the block void, but I don't see any masonry boxes like that with a quick search.

True, I forget this sometimes. I am sure you will figure out a way to secure it. More than one way to skin a cat.