Concrete anchor


Old 12-07-06, 10:50 AM
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Concrete anchor

I'm looking for some opinions on how to best mount conduit and load centers on a poured foundation wall. I have had horrible luck with masonary bits and concrete anchors. I noticed a hex head on a screw mounting for my current panel, and I couldn't find anything like that at the home center. The ones I saw looked pretty cheap and worked in a variety of ways.

I ended up buying some that have a nylon securing bolt on the end that causes the sleve to deform. I imagine they could work well for me, but the install time will be great. I also tried some lead sleaved ones, but they only had nails to drive them in. I am considering using the lead sleave and attaching with a metal sheet screw.

So are there any preferred methods?
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Old 12-07-06, 12:54 PM
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I just got done mounting my load center not long ago. It is on a block wall but should make no difference for a poured concrete. What I did was cut a 3/4" piece of plywood to put behind the loadcenter. I then used 2 1\2" wood screws at the top and screwed the ply into the piece of wood that runs along the top of the blocks. I then used a ramset to shoot 6 fasteners (3 down each side) equally spaced through the wood into the block. I then mounted the load center to the ply with 3/4" #12 wood screws with washers under the heads. It is solid. For conduit I just used the plastic inserts with the screws that come with them. The masonary bits work much better with a hammer drill. The hex head you saw was probably a tapcon (a concrete screw that requires no insert). Is it blue? That is another option but still requires a special masonary bit to use.

Last edited by jetmx; 12-07-06 at 03:44 PM. Reason: added text
Old 12-07-06, 01:11 PM
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>>horrible luck with masonry bits and concrete anchors

That pretty much describes how I felt until I realized there is a huge difference between 3/16 masonry screws and 1/4" masonry screws. 1/4" Tapcons are the bomb. It seems like the 3/16 screws either don't have the threads to grab, or the masonry bit rounds out the hole too much for them to grab. I only use 1/4" tapcons now and rarely will one "spin out". If it does spin, you likely just need a longer one. And don't overtighten them. For attaching conduit, you'd probably use a 1/4 x 1 1/4" screw. Hex heads work great on standard drivers (or optional hammer setting) and phillips heads work great if using an impact driver.

A Bosch 1 1/8" rotary hammer also works better if you have a lot of holes to drill- it makes drilling into concrete seem like fun compared to smaller hammer drills- its effortless. The little 1/2" Milwaukee Magnum hammer drill we have just gathers dust now.
Old 12-07-06, 01:43 PM
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Wow, some useful things here. I have a Milwaukee 1/2" hammer drill, big heavy sucker. I've already burned through one of the kits masonary bits.

Yes, I used the blue tapcon anchors. They don't seem to do well for me. The ones in my panel were silver with a philips head. I wonder if they used some sort of plastic sleave or lead. Either way, I'm probably done using these Tapcons.
Old 12-07-06, 01:47 PM
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But were they 3/16" tapcons? If so, I think they're junk too. That was what I was getting at... if you used 3/16" ones, try to get some 1/4" tapcons- they hold better.

It also could be that you were using a masonry bit that was slightly too big?
Old 12-07-06, 02:32 PM
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Good quality rotary impact bits (not cheap masonry bits for a regular drill) and a good quality hammer drill are essential. If it's poured concrete even with good quality rotary impact don't expect them to last for more then a few holes at best and always drill a smaller diameter hole first. Don't even try with a regular drill. Rent beg or borrow a hammer drill.

If using Tapcons always use Tapcon bits not just any bit. They are specially sized. Avoid philips head, too easy to strip, use hex.

Last edited by ray2047; 12-07-06 at 02:25 PM. Reason: Add info.
Old 12-07-06, 02:54 PM
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as Ray posted, Tapcons use a special sized bit. If you don't use it, the holes are going to be too small (you'll break screws) or too large (they will strip out).

on this page:

you will see.

several methods that will work for you. I tend to use the machine screw anchors (I have always called the hollow wall anchors becaused you can use them in block walls) but they require a special tool to install that is about $40. Not worth buying for just a few.

a friend of mine swears by the "wedge anchors" and I have used them, the sleeve anchors, drop in anchors, and single expansion anchors.

any one of them would work for you.

wedge anchors work well and I also like the sleeve anchors
Old 12-08-06, 06:11 AM
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I've used about every type of anchor. I find the plastic sleaves to be the most versatile and forgiving ones. I've also used alot of tapcons, definately use the hex head bit. I personally don't like the tapcon drill bits, they don't last very long. I've had much better luck with the brand name bits like "blue titanium".
Old 12-08-06, 07:19 AM
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Thanks for the replies everyone.

I'm mouting my Gentran transfer switch this weekend and wanted to be sure it stayed on the walls. I might try the plastic sleave ones, I thought that the lead would be better, but I'll give it a shot.

By the way, if anyone wants one, Amazon is having a crazy sale on them. They have $50 off once you cross the $300 mark AND 10% off. I was able to get my 16 circuit gentran for around $264 delivered, no tax. No reason not to hook one up at that price.

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