Best way to mount an LB conduit body on thick brick?

Mounting an LB an inch off the wall with offsets is going to look like another hack job, even if it is technically more proffesional than just a wire poked through a hole. You realy want that back hub flush against the masonry for a solid installation and a clean seal. If you leave it floating, you are relying entirely on the conduit to support the weight of the LB, which isn't ideal for a long-term outdoor setup, expecially with a pool pump that might see some vibration or physical traffic nearby.

You do not actually need a massive 1 3/8 inch SDS bit to get through the whole depth if you approach it differently. One trick is to use a standard diamond hole saw—the kind meant for tile or stone—to get through the brick face first. Once you are through the brick, you can usually switch to a smaller hammer drill bit and "stitch drill" a circle or just use a cold chisel to knock out the center of the block. It is a bit more labor-intensive but it saves you from buying a specialty bit you will only use once. If you absolutely cannot get it flush and decide to mount it proud, do not just let it hang there. Use some **shallow strut** or a mounting block behind the LB to give it a solid surface to bolt into. If it is just floating, you are asking for the caulk to fail within a year as the pipe expands and contracts. A solid mount is what prevents leaks, not just the amount of sealant you pump into the gap. Also, make sure you address **NEC 300.7(A)** while you are at it. Since you are going from a crawlspace to the outside, you have to seal the inside of that conduit with duct seal or an approved sealant. If you skip this, warm air from the crawlspace will hit the cold LB and you will end up with condensation building up inside the pipe. That moisture will eventually sit in the bottom of the LB and can cause issues with your wire insulation or trip the GFCI prematurely. A handful of duct seal is cheap insurance.

I’m nervous about using a hammer drill on my old brick. Is there a high risk of cracking the face of the brick if I go too fast? I’ve seen some people use those star drill bits with a manual hammer, but that seems like it whould take forever. Also, that duct seal stuff—is it just like a putty you shove in there? Does it ever harden or do you have to replace it every few years when it dries out? I’m worried about it getting messy if I ever need to pull new wires later on.

If you’re worried about cracking that old brick, keep the drill on the high-speed rotation setting only untill you’re trough the exterior face. Only flip to 'hammer' once you hit the backup block. It’ll take a minute longer but prevents that ugly spalling. As for the duct seal, it’s basicly like Play-Doh that never dries out. You just wad it up and jam it around the wires inside the pipe. It’s meant to stay pliable so you can pull it out later if you ever need to swap a circuit. Just make sure you don't overstuff it or you'll have a hard time getting the LB cover back on once the wires are in.