In my old space, I used a large hose clamp. The clamp went around the
column, into the back of the box through a knockout, around a bit of
steel rod, back out the knockout. This worked well, but it was a bit
Is there a commerically available clip or bracket that is used to
mount surface mount electrical boxes or EMT to lally columns?
Thanks for any suggestions you may have.
There are metal epoxies that would mount a plate to the column.
Hilti powder actuated nail gun and Hilti threaded studs (1/2" long, for
steel). Shoot in two studs to line up with the holes in the back of the
electrical box, then secure with nuts and lockwashers. In the event the
box needs to be removed, you can readily grind off the studs with an
angle grinder and touch up paint it.
All sorts of masonry anchors out there, I've used tons to mount
various electrical boxes to concrete and block walls. I used to work
in one of the first poured concrete buildings, made about 1917, the
support columns were round and all electrical boxes were mounted that
way with conduit running up to the ceiling to junction boxes. The
column diameters were about 4' on the the floor we had the warehouse
on, would have taken a hell of a hose clamp to span that.
That's a lot of effort to cut the piece of 1/8 x 1, drag in a welder,
find power, weld, cool, etc. vs. spending 1 minute with the Hilti.
Not if you don't have a Hilti. And do have a welder <G>. Bob
Home Depot rents the Hilti DX36M (I own one), I'm not sure if they carry
the threaded studs, but you can get them from the local Hilti store.
If I rented the Hilti, could I not just use short nails/pins and blast
right through the back of the box into the colunm?
I do have a welder, but new shop is not wired for it......Until I run
Thanks, and keep the suggestions comming.
The problem is that these columns (I call them lally columns in
Northeast USA) are steel tubes around 4 inches in diameter, filled
with concrete. Will a hammer drill with a masonary bit drill though
steel? I will have to experiment.
my Hilti has come up missing.....damnit
'In the first place, we should insist that if the immigrant who comes here in good faith
becomes an American and assimilates himself to us, he shall be treated on an exact
equality with everyone else, for it is an outrage to discriminate against any such man
because of creed, or birthplace, or origin. But this is predicated upon the
person's becoming in every facet an American, and nothing but an American...
There can be no divided allegiance here. Any man who says he is an American,
but something else also, isn't an American at all. We have room for but one flag,
the American flag... We have room for but one language here, and that is the
English language.. and we have room for but one sole loyalty and that is a
loyalty to the American people.'
Theodore Ro osevelt 1907
>I do have a welder, but new shop is not wired for it......Until I run
You cant make an extension cord?????????
Piece of 1" plywood U-bolted to the column.
I don't know if it's to code, so check with an electricaltician (Bruce
Bergman, a Sparky here on RCM), but drilling the column with a masonry
bit is simple, and various methods of fastening through it are to
code. The simplest is a plastic insert in an oversized hole for that
particular screw. It's an additional 5 minutes over the 5 minutes
with the Hilti, but not if you have the masonry bit and don't have a
If you are distressed by anything external, the pain is not due to the
thing itself, but to your estimate of it; and this you have the power
to revoke at any moment. -- Marcus Aurelius Antoninus
> On Aug 17, 1:14�pm, andy <ah...@lynnwatersewer.org> wrote:
>> Hi Folks. �I am in the process of wiring a basement workshop. �I
>> to have some 110 volt and 220 volt receptacles mounted on steel
>> columns which hold up the first floor. �The columns are filled with
>> concrete, so just screwing my surface mount boxes to the column is
>> out. �Does anyone know how this is done "in the trade" or has
>> seen this done in a neat fashion that they would like to describe?
The common way here is to power-nail a mounting plate to the column.
> In my old space, I used a large hose clamp. The clamp went around the
> column, into the back of the box through a knockout, around a bit of
> steel rod, back out the knockout. This worked well, but it was a bit
> "homegrown" looking.
> Is there a commerically available clip or bracket that is used to
> mount surface mount electrical boxes or EMT to lally columns?
> Thanks for any suggestions you may have.
I kind of like the hose clamp. Might look better if the hose clamp
was silver brazed to the box and the box painted to match the column.
The obvious solution that would likely be used by an electrician is
cable ties. Quick, Easy, and Cheap. Would look better if some clips
were screwed to the box, instead of running them thru the box.
Thanks for all the replies.
So far, the ramset (Hilti) solution is out in front. I will post to
the dropbox with my solution.
You could start with a metal drill to get your hole location and not
through to the concrete. Then use a sharp carbide drill for concrete
to finish going through the steel and into the concrete. Don't use a
hammer drill while drilling in steel, just rotary. Then use concrete
anchors to hold your box.
Metalworking group or not, the easiest thing to do is "box in" the
Lally column, with 2 X ?? or even "thinner". "Pin it" through the top
adjust hole of the Lally to keep it in place.
I would not use a Ramset powder actuated tool on filled structural
steel lally columns like that, part of their strength is the concrete
inside, and if you fracture it the strength is reduced.
Myself, I'd stay with the hose clamps to attach a chunk of Unistrut
vertically on the pole, or tack-weld a piece of Unistrut to the column
for the conduit risers and some flat plate to mount the boxes - that
won't affect the concrete filling, and small tack beads shouldn't hurt
the steel column strength enough to matter.
If you attach the Unistrut to a floor bracket and anchor the top off
to the beam, you only need one hose clamp in the middle around the
column or a few short tack welds, mainly to keep it from bending when
you trip over an extension cord.
If these were open internally reinforced concrete columns (Sonotube
cardboard forms) I'd still be wary of using a Ramset on them, for the
same reason - fracture the concrete and you are counting on the rebar
alone to carry the entire load.
(This is why they are reinforcing freeway bridge columns with steel
bents on the outside - if the concrete fractures in an earthquake, the
steel outer skin will hold all the pieces in place and keep it from
You can put a 1/4" hole with a carbide impact drill fairly safely
and use a plastic anchor or a zinc sleeve and pin fastener, but a
Ramset can cause a lot of damage with a single shot.
(Not to mention the fun of a "Come-backer" nail bouncing off ultra
hard old concrete and moving at ballistic speeds. Been there, Done
that, sweating my butt off in a heavy jacket for padding...)
--<< Bruce >>--
Not an issue. The concrete provides only compressive strength and that
is not compromised even if it has some cracks in it. The 1/2" long pins
won't fracture the concrete either.
> Myself, I'd stay with the hose clamps to attach a chunk of Unistrut
> vertically on the pole, or tack-weld a piece of Unistrut to the column
> for the conduit risers and some flat plate to mount the boxes - that
> won't affect the concrete filling, and small tack beads shouldn't hurt
> the steel column strength enough to matter.
If you're going to weld, just plug weld the box to the column via the
normal box mounting holes and be done with it. It will be a much cleaner
looking job, and again can be ground off with an angle grinder if the
box needs to be removed. I've plug welded several electrical boxes to
frames made of square steel tube and it works fine.
> If you attach the Unistrut to a floor bracket and anchor the top off
> to the beam, you only need one hose clamp in the middle around the
> column or a few short tack welds, mainly to keep it from bending when
> you trip over an extension cord.
Good grief, $20 in materials to do the job of $0.50 worth of Hilti pins
and loads, or $0.10 of weld?
> If these were open internally reinforced concrete columns (Sonotube
> cardboard forms) I'd still be wary of using a Ramset on them, for the
> same reason - fracture the concrete and you are counting on the rebar
> alone to carry the entire load.
You need to understand that concrete provides compressive strength only,
it could be dry stacked concrete blocks and provide the same strength.
The rebar is always what provides strength against flexing loads.
> (This is why they are reinforcing freeway bridge columns with steel
> bents on the outside - if the concrete fractures in an earthquake, the
> steel outer skin will hold all the pieces in place and keep it from
Which is exactly why fractures in the concrete inside a lally column are
irrelevant and why shooting the boxes on with Hilti pins is fine.
> You can put a 1/4" hole with a carbide impact drill fairly safely
> and use a plastic anchor or a zinc sleeve and pin fastener, but a
> Ramset can cause a lot of damage with a single shot.
A Ramset or Hilti can cause a lot of damage if used on the web sections
of a non-filled block wall, they will do no harm at all to a concrete
filled steel column.
> (Not to mention the fun of a "Come-backer" nail bouncing off ultra
> hard old concrete and moving at ballistic speeds. Been there, Done
> that, sweating my butt off in a heavy jacket for padding...)
Also not an issue when shooting the proper 1/2" pins into the steel
Besides, the Hilti is kind of like a firearm, and the second amendment
ramifications of this job are huge. Sorry, I just couldn't resist.
Seriously, my initial thought was similar to Bruce's - that you could
really screw up the concrete and compromize the strength of the
column. But Pete's explanation sounds pretty good. The concrete is
only providing compressive strength, a fracture is not removing any
material (assuming that there arent any huge voids), so this should
work fine, and take all of couple of minutes, start to finish. And, it
will smell like gunpowder, which is always good for the folks in this
> The obvious solution that would likely be used by an electrician is
> cable ties. Quick, Easy, and Cheap. Would look better if some clips
> were screwed to the box, instead of running them thru the box.
You can't attach the box with cable ties. We used saddle strap which
is a cut to fit type of hose clamp. If you can find large enough hose
clamps most inspectors would probably be OK - use two so the box
can't twist. If the box is below six feet feet from the ground you may
need to protect the cables with plastic conduit to that height.
One can mig weld an electrical box up in less than 15 seconds. Works
great, less filling.
Whenever a Liberal utters the term "Common Sense approach"....grab your
wallet, your ass, and your guns because the sombitch is about to do
something damned nasty to all three of them.
What filler rod do you use to fasten them to concrete columns, sir?
(This I -gotta- hear. ;)
So far Mr. Obama has used his personally exciting presidency for initiatives
that are spending public money on a scale not seen since ancient Egypt.
-- Daniel Henninger
WSJ Online, 4 June 2009
"Obama's America: Too Fat to Fail
The age of the induced industrial coma."
Doesn't the galvanizing fuck up the weld? I think I'd drill the
mounting hole just a touch bigger (to drill off the galvy) & plug weld.
> What filler rod do you use to fasten them to concrete columns, sir?
> (This I -gotta- hear. ;)
Per this in the OP: "...steel lally
>>>columns which hold up the first floor. The columns are filled with
I'm just guessing plain ol' 6011 ought to work fine <G>.
(I'd still Hilti 'em in)
It is an electrical box. How much force is it going to have to stand?
Besides the Ramset is more fun than welding.
JB Weld of course!
Didnt they teach you anything?
>So far Mr. Obama has used his personally exciting presidency for initiatives
>that are spending public money on a scale not seen since ancient Egypt.
> -- Daniel Henninger
>WSJ Online, 4 June 2009
>"Obama's America: Too Fat to Fail
>The age of the induced industrial coma."
Whenever a Liberal utters the term "Common Sense approach"....grab your
Isnt it amazing how some people just never bother reading ALL the words?
Gunner, who occasionally does the same.
Not really, but if the urge strikes, hit the welding surfaces with a
coarse wire wheel or even a grinder. Just break the galv and the weld
will lift up the rest.
Gunner, who welded a bunch of electrical boxes to his shop walls and
No, it doesn't, just don't breathe the zink laced fumes. For mounting an
electrical box to a column, metallurgical weld perfection is not
required, and the galvanizing burns off anyway.
Update on my mounting electrical boxs to concrete filled steel lally
boxes were mounted using #10 x 0.5" drill-tip screws. The first batch
I drilled the hole through the steel with the drill tip portion of the
screw. I then chipped away a little of the concrete fill with a
hammer and nail. Next I ground the drill tip off the screw with a
bench grinder, finally I mounted the box with the "sawed off" screw.
This was a bit tedious, but still didn't take much time.
The second batch I just leaned into the drill-tip screw and mounted
the box in one shot. Some of these went in a little crooked, but will
hold the box on just fine.
I guess my summary would be: if you are not bothered by the screws not
going in perfectly normal to the back of the box, then to just bear
down with the drill tips and go to town. If you are a perfectionist,
you may want to go with the drill, chip, grind, mount program
I promised drop box photos, but it really is not that exciting and my
pics didnt' come out very well.
Thanks for the help,