Hi there,

My masonry contractor has run some conduit in the pilasters of my new concrete block retaining / garden wall. I'd like to mount exterior lamps on the sides (not the tops) of the pilasters to match the lamps I have near my front porch and around the sides of my house. The lamp looks like this:

Attachment 47443
My masonry contractor seems really uncertain about the right way to do this in line with electrical code though. He wants to just pop the wires out of a tiny hole and drill the lamp into the block surface mount style. By contrast, I want to have full round or rectangular boxes placed into the block so that there's sufficient room for the wires and so that I can easily change the lamps in the future.

What's the right way to do this? How do we protect against moisture? What does code require?

To give you a sense for the project, here's what the wall looks like -
Attachment 47442

One last thing. My plan is to just have the mason run the conduit and mount the boxes into the CMUs, and then at a future time to run the electrical wire through the conduit and tie it into the electrical panel. I separated the project like this because I wasn't quite ready to pay an electrician. I do plan to get the electrical work permitted and inspected (I may end up doing the electrical work myself) but there may be a few months gap in between having the inspector sign off on the completed wall and when the electrical gets ran.

Thanks!

Since he knew what you wanted to do he should have put in a mounting block in the wall. Since you say this will be inspected you must get a permit. Some towns will not allow you to DIY electrical work outside. Do you have a GFCI on this circuit? I would mount a pressure treated block of 2x6 which is about 3" longer than the back of the fixtures base. Mount the block with masonry screws or tap-cons.

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Originally Posted by ballengerb1

Since he knew what you wanted to do he should have put in a mounting block in the wall. Since you say this will be inspected you must get a permit. Some towns will not allow you to DIY electrical work outside. Do you have a GFCI on this circuit? I would mount a pressure treated block of 2x6 which is about 3" longer than the back of the fixtures base. Mount the block with masonry screws or tap-cons.

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AFAIK my county (unincorporated area) will allow me to do the work but will want it inspected. Can you tell me more about what you mean with using the treated wood block? I'm having trouble visualizing it.

My mason just stopped by a few minutes ago to talk about the lighting and he seems to think now that we can install any kind of box, but that it's the lighting fixture that matters. He suggested either getting a light with some type of built in waterproofing gasket (I haven't seen one of these before) or fashioning a gasket of sorts out of silicon or something to make my chosen light work.

I'm guessing normally that the light I picked is meant to go under the eave of a house, so water proofing may not matter as much. What's the right way to mount this style of light to an outdoor wall with an irregular split face surface though?

Regarding the GFCI question, yes I planning to run a new 20amp branch connected to a GFCI breaker.

Anybody have links or photos to a well installed lamp on the side of a split face wall? If not that, what about a link to a lamp that's intended for that kind of application? Maybe if I can see an example that would help.

Retaining wall lighting

Product Information

Your mason might know bricks but not electricity. You need a flat surface for a mounting block. Buy a few feet of pressure treated (Wolmanized) lumber 2x6". Cut two pieces 3" longer than the fixture mounting plate is tall. Anchor these two wood blocks to the wall with Tapcons or other masonry screws. Now add your light mounting block which will accept your fixture. Shop Builders Edge 8-in x 12-in Gray Standard Mounting Block at Lowes.com

All electrical connection must be made in an approve electrical box. Whether the canopy of your fixture is an approved electrical box I don't know
If the wall has not been built have the mason imbed a water proof box. If wall has been built have him chisel out and install the box.

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I want to have full round or rectangular boxes placed into the block so that there's sufficient room for the wires and so that I can easily change the lamps in the future.

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All electrical requirements aside, the rule is "He who has the gold makes the rules"
You are the one paying the bill aren't you. Demand your boxes.

The fixture shown would be approved for under a porch, a damp location, but probably not for a wall without a cover, a wet location.

PS,
Doesn't cost anything to call the inspector and ask.

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Originally Posted by ballengerb1

Your mason might know bricks but not electricity. You need a flat surface for a mounting block. Buy a few feet of pressure treated (Wolmanized) lumber 2x6". Cut two pieces 3" longer than the fixture mounting plate is tall. Anchor these two wood blocks to the wall with Tapcons or other masonry screws. Now add your light mounting block which will accept your fixture. Shop Builders Edge 8-in x 12-in Gray Standard Mounting Block at Lowes.com

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Thanks ballengerb1, that's a good point. A flat surface makes sense but I worry that the treated wood might interfere with the look of the light. I wonder how difficult it would be to use a grinder to flatten out part of the splitface texture on the block?

Hi hkstroud,

The lamp manual says "cCSAus Wet location listed". (1) Does that mean that the lamp is likely okay for mounting on this block wall without roof cover?

(2) Is this the right type of box to use?
Attachment 47457

(3) Do I need any kind of gasket between the box and the lamp? The lamp didn't come with anything like that and the manual doesn't mention it.

Manual attached - Attachment 47458

Thanks!

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The lamp manual says "cCSAus Wet location listed"

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Yes

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(2) Is this the right type of box to use?

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Yes, however box shown is made for surface mount.
Call inspector, may not need a water proof box if imbedded in wall. What kind of conduit? EMT or rigid conduit. Box and conduit need to be compatible.

Mounting instructions say,

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• back plate covers a standard 4"

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If no other method of sealing provided mount box and silicone around.

You need a box that will fit inside of the light canopy. You will need to caulk around the edges of that canopy. There are flat (pancake) boxes that are designed for light fixtures. They have a knockout(s) on the back side only. They are available in metal or plastic. Then you will have mounting screw holes that will allow you to change fixtures.
Again, once it's attached you will need to caulk around it. MOST exterior fixtures have a canopy deep enough to cover the box. If not, you can use a mounting plate on the will without a box. If the fixture is approved, the canopy itself IS the junction box.

Thanks hkstroud and Missouri Bound.

Funny story... I used some fish tape to run pull string through the 3 U-shaped conduit loops yesterday (there are 4 pilasters in total) or rather I should say that I tried. Only one of the three loops was open. The masons dropped wet concrete into the other two and it clogged the pipe at the 90s. They had fun digging those out this morning.

I've had absolutely zero luck finding Wet Location boxes that can be embedded into the blocks. As you pointed out hkstroud, the box I posted a picture of is a surface mount box. The other rectangular box that I found had the mounting holes in the wrong places for connecting to the conduit within the block. I'm also a little concerned about the structural integrity of the block with such large holes being cut in (the wet location boxes are larger).

This morning my mason showed up with regular old single-gang, rectangular, galavanized steel boxes. I'm inclined to let him install those since they won't require large holes in the blocks.

Do you guys think this is a reasonable approach? Or am I asking for trouble by not using web location boxes? If these steel boxes are embedded into the blocks will they count as being in a "Damp location" instead of a "Wet location"? And will galvanized steel be acceptable?

I've seen that done more times than I can count. When those are used you have to seal the fixture to the wall as I mentioned earlier. As far as the mounting holes in the fixture go: There is a fixture bar that mounts to the box then the fixture mounts to the bar. This allows the fixture to be straightened if the box is crooked and allows for different spacing should the installer use a non-standard box. Some of those "bars" are actually two bars joined in the center that swivel and there are also round bars which are more like plates with slots and perforations over the entire surface.
After the boxes are mounted, go to an electric supply store and tell them what box is used and what fixture you are using... but I'm thinking the fixture bar should come with the fixture... it usually does.

Have you called the inspector and ask if box has to be water proof?