What do you guys thing about folks that use a minnie strap/conduit clips on the end of a piece of all thread screwed into the ceiling as support for a raceway? I have seen this a number of times, its strapped every 10 feet, 3 feet from boxes ect. but it really only has support from a vertical movement. 3/8 all thread is pretty rigid, but you can push/bend it a ton on the horizontal plane. I am trying to do a bunch of data drops with one inch conduit in very conjested ceilings. The cement hard ceiling is over 15 feet AFF. The drop ceiling is at 8' The concrete lid is full of ducts, concrete support columns ect., however at about 12 feet it's clear sailing for every drop. Minnies seem like a good idea. Each room has 6 drops in it. They all originate from a cable tray in the hall, and the thought was build a nice trapeze rack to get into the room and then turn off to feed each drop. This would mean just one conduit heading to its own drop and trying to get on the ceiling is just not a good option. Any good ideas on how to stay at a lower elevation and still have a clean and quality raceway installation?? I have never really liked the caddy stuff that hangs conduit off drop wires. Just wanting to see what others think.
Using a Minnie strap/ Conduit Clips as addiquate raceway
- Thread starter copper123
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
What size conduit are we talking about? There is nothing wrong with hanging conduit from 3/8" rod as you've described. We typically would install up to 4" EMT using Mineralac hangers and 3/8" rod for a single conduit run. The key being how well it is anchored into the structure above.
What size conduit are we talking about? There is nothing wrong with hanging conduit from 3/8" rod as you've described. We typically would install up to 4" EMT using Mineralac hangers and 3/8" rod for a single conduit run. The key being how well it is anchored into the structure above.
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
Thanks for the reply.
In this installation its just 1" Emt run down from the hard concrete lid with 3/8 allthread. Some folks think that this installation is a little cheese as it really is not a hard strap. It gets worse the farther the drop hangs downs. Pretty loose.
Thanks for the reply.
In this installation its just 1" Emt run down from the hard concrete lid with 3/8 allthread. Some folks think that this installation is a little cheese as it really is not a hard strap. It gets worse the farther the drop hangs downs. Pretty loose.
sandsnow
Senior Member
- Location
- Southern California
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
Refer to 300.11(A)
Raceways....shall be securely fastened in place.
Does a 3/8 rod do this? The answer is no most of the time. The sway you get as the length of the rod increases as well as the length of the conduit run increases would be a violation of the code.
It is accepted practice most everywhere and has been for many years. I would be interested in hearing about places where it is not.
That being said, who wants to change the world
Refer to 300.11(A)
Raceways....shall be securely fastened in place.
Does a 3/8 rod do this? The answer is no most of the time. The sway you get as the length of the rod increases as well as the length of the conduit run increases would be a violation of the code.
It is accepted practice most everywhere and has been for many years. I would be interested in hearing about places where it is not.
That being said, who wants to change the world
- Location
- Massachusetts
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
Copper above suspended ceilings this is very common.
IMO you also have to consider the likelihood of people messing with the pipe run.
When I run pipe that is within reach of people I pride myself on securing the heck out of it.
Above a suspended ceiling is different, few people will go up there and damage the pipe runs.
For a 1" EMT run I might even use 1/4" rod, it won't make much difference neither will hold the pipes side to side but with 1/4" I can use a ramset if I want.
I do recommend quality steel couplings are used, die casts will break if someone does flex the pipe.
Copper above suspended ceilings this is very common.
IMO you also have to consider the likelihood of people messing with the pipe run.
When I run pipe that is within reach of people I pride myself on securing the heck out of it.
Above a suspended ceiling is different, few people will go up there and damage the pipe runs.
For a 1" EMT run I might even use 1/4" rod, it won't make much difference neither will hold the pipes side to side but with 1/4" I can use a ramset if I want.
I do recommend quality steel couplings are used, die casts will break if someone does flex the pipe.
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
Thanks I wire
I to have done this before, but as the gentleman above has stated, it is pretty loose. I wonder how many people run conduit this way and not carry a grounding conductor? Have you ever supported your conduit with a tie wire attached to the ceiling grid and the ceiling? All the areas I have been that have this insallation are just as you would think. Disjointed and the like. I have never done it, and won't. Thanks for the reply.
Thanks I wire
I to have done this before, but as the gentleman above has stated, it is pretty loose. I wonder how many people run conduit this way and not carry a grounding conductor? Have you ever supported your conduit with a tie wire attached to the ceiling grid and the ceiling? All the areas I have been that have this insallation are just as you would think. Disjointed and the like. I have never done it, and won't. Thanks for the reply.
- Location
- Massachusetts
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
If you are really bothered by the side to side motion you could use two rods and two minnis at each support location with the rods splayed out in a "V" fashion.
Not really many ways to make this solid if you feel it needs to be.
You could switch to RMC with threaded couplings.
If you are really bothered by the side to side motion you could use two rods and two minnis at each support location with the rods splayed out in a "V" fashion.
Not really many ways to make this solid if you feel it needs to be.
You could switch to RMC with threaded couplings.
luckyshadow
Senior Member
- Location
- Maryland
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
We run conduit like that all the time. Standard practice. 1" conduit - 1/4" all thread. We use the ramset/hilti gun, with a 8' extension, to shoot studs into the concrete deck. Then we place a 1/4" nut and rod coupling on the rod and screw it to the stud. Using this method we only need a 8' or 10' step ladder to reach those high decks.
We run conduit like that all the time. Standard practice. 1" conduit - 1/4" all thread. We use the ramset/hilti gun, with a 8' extension, to shoot studs into the concrete deck. Then we place a 1/4" nut and rod coupling on the rod and screw it to the stud. Using this method we only need a 8' or 10' step ladder to reach those high decks.
sandsnow
Senior Member
- Location
- Southern California
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
Just nitpicking
Yes. This was acceptable when I started here and still is.
Just nitpicking
cselectric
Senior Member
- Location
- Wisconsin
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
I see no problem with this install (except the nuisance of having to drill out the minnies to accept a 3/8" rod. ) I've actually done entire rooms this way, suspending not only pipe supports, but boxes from drop rods. When you have an 8' lid and a 20' pan, and the room is too wide to reach the center from the walls, what else can be done?
I see no problem with this install (except the nuisance of having to drill out the minnies to accept a 3/8" rod.
) I've actually done entire rooms this way, suspending not only pipe supports, but boxes from drop rods. When you have an 8' lid and a 20' pan, and the room is too wide to reach the center from the walls, what else can be done?tx2step
Senior Member
- Location
- North Texas, DFW area
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
This is pretty much standard practice, and I've not seen very many problems with it.
From a practical point of view -- how else would you do it and be cost effective?
I've seen a lot of small EMT run off of separate ceiling type support wires using caddy clips. I know you said you don't like them, and I don't use them very often either, but they will support the conduit just fine and don't sway much worse than long 1/4" rod. I've not seen many problems with that method, either. They can be installed using a hilti or ramset (with extension) from the grid level.
As Bob said, conduit damage isn't usually a problem since there's not usually much happening above a suspended ceiling. Hopefully anyone working up there is at least semi-qualified in some trade.
This is pretty much standard practice, and I've not seen very many problems with it.
From a practical point of view -- how else would you do it and be cost effective?
I've seen a lot of small EMT run off of separate ceiling type support wires using caddy clips. I know you said you don't like them, and I don't use them very often either, but they will support the conduit just fine and don't sway much worse than long 1/4" rod. I've not seen many problems with that method, either. They can be installed using a hilti or ramset (with extension) from the grid level.
As Bob said, conduit damage isn't usually a problem since there's not usually much happening above a suspended ceiling. Hopefully anyone working up there is at least semi-qualified in some trade.
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
Thanks for the all the information guys. The power of the net! I have never seen a actual 1/4" sammy type female connector that can be shot from a hilti gun. I have seen the extensions that shoot a stud with a wire on the end for ceiling installations but never the female coup. I will jump on the Hilti site!. Thanks for the all the responses!
Thanks for the all the information guys. The power of the net! I have never seen a actual 1/4" sammy type female connector that can be shot from a hilti gun. I have seen the extensions that shoot a stud with a wire on the end for ceiling installations but never the female coup. I will jump on the Hilti site!. Thanks for the all the responses!
tx2step
Senior Member
- Location
- North Texas, DFW area
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
I think they were describing using a threaded male stud (with 1/4"-20 male threads) shot into the concrete (using a pole-tool extension).
Then thread a 1/4-20 hex nut onto the end of the 1/4" rod, then a 1/4" threaded rod coupling. Run the rod coupling to the right depth and jam it in place on the rod with the 1/4" hex nut. Then screw the rod coupling/rod onto the stud from below (standing at a comfortable height in the grid).
I don't think that Hilti makes a stud with female threads -- just with male threads.
I'm not sure about Ramset, but I think theirs are also male threaded studs.
I think they were describing using a threaded male stud (with 1/4"-20 male threads) shot into the concrete (using a pole-tool extension).
Then thread a 1/4-20 hex nut onto the end of the 1/4" rod, then a 1/4" threaded rod coupling. Run the rod coupling to the right depth and jam it in place on the rod with the 1/4" hex nut. Then screw the rod coupling/rod onto the stud from below (standing at a comfortable height in the grid).
I don't think that Hilti makes a stud with female threads -- just with male threads.
I'm not sure about Ramset, but I think theirs are also male threaded studs.
macmikeman
Senior Member
- Location
- Planet macmikeman
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
You know its not just the end of the rod that can carry the conduit. You can also put caddy k-12's along the rods for multiple runs of conduit, but I would watch out for total weight of this style.
You know its not just the end of the rod that can carry the conduit. You can also put caddy k-12's along the rods for multiple runs of conduit, but I would watch out for total weight of this style.
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
[ September 17, 2005, 09:24 AM: Message edited by: geezer ]
Larry, Do you require a grounding conductor in the conduit for these types of installations? It would seem to be a reasonable requirement, though probably not needed IF the installation is RMC with properly tightened couplings.
[ September 17, 2005, 09:24 AM: Message edited by: geezer ]
- Location
- Massachusetts
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
An inspector can not require it, as the NEC does not require it.
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
This is just my opinion, but I try to avoid using 1/4" rod if I'm hanging the pipe more than 6 or 8 inches from the deck. It's just a bit too flimsy for me. In your case, if 1/4" is just a lot more practical, I would decrease my spacing between supports to 6 feet max. And steel fittings too, as a previous post said.
John
This is just my opinion, but I try to avoid using 1/4" rod if I'm hanging the pipe more than 6 or 8 inches from the deck. It's just a bit too flimsy for me. In your case, if 1/4" is just a lot more practical, I would decrease my spacing between supports to 6 feet max. And steel fittings too, as a previous post said.
John
Re: Using a Minnie strap/ Conduit Clips as addiquate raceway
So, what is the difference between steel fittings and Diecast fittings? Are you guys talking about the difference between set screw and compression or the actual dif. between steel and cast? It would appear that the consensus is that a cast set screw fitting might crack and break in loose environment as it has been described? I guess I have not seen a cast fitting crack before.
So, what is the difference between steel fittings and Diecast fittings? Are you guys talking about the difference between set screw and compression or the actual dif. between steel and cast? It would appear that the consensus is that a cast set screw fitting might crack and break in loose environment as it has been described? I guess I have not seen a cast fitting crack before.
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