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Unistrut for Wiring Drop

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Forum topic by Steinbierz posted 04-05-2020 02:29 PM 372 views 0 times favorited 20 replies Add to Favorites Watch
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Steinbierz

99 posts in 866 days


04-05-2020 02:29 PM

Hello,

I have several pieces of equipment that will need to be in the middle of the floor of my steel building shop and i would like to do ceiling drops for the power. I have read where people have used unistrut as their drop but the posts didn’t go into much detail or include pictures.

I was wondering if I could simply through-bolt the unistrut channel in the ceiling purlins and drop it down vertically to where I need it and then run conduit down from the ceiling along the channel to a j-box? If necessary, I would take a short piece or two of channel and brace the drop at the ceiling to give it more rigidity. Thanks for any thoughts or pictures that others could share.

-- Larry ~ Alvin, TX (Home of Nolan Ryan)


20 replies so far

View CaptainKlutz's profile

CaptainKlutz

2987 posts in 2224 days


#1 posted 04-05-2020 03:23 PM

:-)

‘Unistrut’ is an erector set for adults.

Your imagination is only limitation on how you use it. Beyond the c channel Unistrut sold at BORG, there is an entire family of structural building components in the family. The trademark owner has PDF documents covering all details. https://www.unistrut.us/resources

This Unistrut application showcase catalog is one of my favorites when I get stuck on how to solve a problem.
‘https://www.unistrut.us/assets/unistrut/Product Application Showcase/’ have to paste into browser.

The Atkore site is not only reference for Unistrut. There are tons of other engineering and service companies that use it to make practically anything.

There is large amount of clone Unistrut sold. The electricians I worked with using truck loads of the stuff would complain the fit/finish was inferior, but it still did the job for hanging cable trays and overhead wiring at work stations. Occasionally the trolley components will not roll as smooth in close stuff, but a little annoying bending/sanding fixes it.

IMHO – it is almost impossible to tell by your description if your application of Unistrut will have issues or not. It reads like a pretty normal use, I.E. to support conduit or wiring trays. Look closely at application pdf and you see how c channel strut is used to hang wiring, and even transformers.

Best Luck!

-- If it wasn't for bad luck, I wouldn't have no luck at all, - Albert King - Born Under a Bad Sign released 1967

View ibewjon's profile

ibewjon

1506 posts in 3522 days


#2 posted 04-05-2020 03:42 PM

That is what it is used for. There are snap in covers to actually use the channel as a wireway, but for you, just buy some Minnie’s, ( picture attached ) bolt to the strut, and run conduit. There are channel nuts that fit inside to bolt to, so nothing sticks out the back. There are many variations of this product, full catalogs of parts.
I have been able to buy small quantities of non big box parts from Garvin industries.

View Steinbierz's profile

Steinbierz

99 posts in 866 days


#3 posted 04-05-2020 04:05 PM



:-) Unistrut is an erector set for adults.

Your imagination is only limitation on how you use it. Beyond the c channel Unistrut sold at BORG, there is an entire family of structural building components in the family. The trademark owner has PDF documents covering all details. https://www.unistrut.us/resources

This Unistrut application showcase catalog is one of my favorites when I get stuck on how to solve a problem. https://www.unistrut.us/assets/unistrut/Product Application Showcase/ have to paste into browser.

The Atkore site is not only reference for Unistrut. There are tons of other engineering and service companies that use it to make practically anything.

There is large amount of clone Unistrut sold. The electricians I worked with using truck loads of the stuff would complain the fit/finish was inferior, but it still did the job for hanging cable trays and overhead wiring at work stations. Occasionally the trolley components will not roll as smooth in close stuff, but a little annoying bending/sanding fixes it.

IMHO – it is almost impossible to tell by your description if your application of Unistrut will have issues or not. It reads like a pretty normal use, I.E. to support conduit or wiring trays. Look closely at application pdf and you see how c channel strut is used to hang wiring, and even transformers.

Best Luck!

- CaptainKlutz

Thanks for the great reply Captain! I am already checking out the link to the catalog that you sent and already have some ideas for other projects e.g. putting my 250# Phase Perfect on my shop wall.

I envision my drop as actually being pretty simple. I plan to drill two holes in my purlin to bolt the unistrut to and drop it down vertically towards my equipment (lathe and sliding table saw). If I have to, I’ll cut one or two pieces to form a triangle at the ceiling for additional support. I am not certain if I would use a full 10’ stick yet as I am still trying to decide how high I want my outlets (240V equipment & 120 accessory) to be located. I guess I won’t know if it will be stout enough until I try it but given the orientation that the channel will be running, the majority of the stress will be on the bolts in the purlin.

-- Larry ~ Alvin, TX (Home of Nolan Ryan)

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Steinbierz

99 posts in 866 days


#4 posted 04-05-2020 04:10 PM



That is what it is used for. There are snap in covers to actually use the channel as a wireway, but for you, just buy some Minnie s, ( picture attached ) bolt to the strut, and run conduit. There are channel nuts that fit inside to bolt to, so nothing sticks out the back. There are many variations of this product, full catalogs of parts.
I have been able to buy small quantities of non big box parts from Garvin industries.

- ibewjon

I have used those fittings that you pictured for other conduit purposes with great success…sometimes bolting them back-to-back to stiffen/support several conduit runs close to each other. Thanks for your idea on using it for my current project!

-- Larry ~ Alvin, TX (Home of Nolan Ryan)

View CaptainKlutz's profile

CaptainKlutz

2987 posts in 2224 days


#5 posted 04-05-2020 04:31 PM

I plan to drill two holes in my purlin to bolt the unistrut to and drop it down vertically towards my equipment (lathe and sliding table saw). If I have to, I ll cut one or two pieces to form a triangle at the ceiling for additional support. I am not certain if I would use a full 10 stick yet as I am still trying to decide how high I want my outlets (240V equipment & 120 accessory) to be located. I guess I won t know if it will be stout enough until I try it but given the orientation that the channel will be running, the majority of the stress will be on the bolts in the purlin.

- Steinbierz

1) They make purlin clamps that hold threaded down rods. No need to drill holes, drilling not recommended in thin gauge purlin’s either.

2) Suggest for suspended applications that you have at least 4 down rods from ceiling supporting your conduit/boxes. Having a ‘box’ or t-shaped structure helps to reduce sway/movement when using overhead outlets, or mobile tools that might pull on hung wires.

3) Wire strain relief is important in any overhead design. Don’t forget need to add separate strain relief support to any overhead wires. The plug can not be used as only support for wire. Again, tons of online references like this one if you have never dealt with this stuff before.

4) Note that any BORG stock of Unistrut accessories behind nuts/clips, like strain relief components can be lacking. Might have to visit an dedicated industrial electrical supply to get all parts you need for proper install.

Cheers!

-- If it wasn't for bad luck, I wouldn't have no luck at all, - Albert King - Born Under a Bad Sign released 1967

View Madmark2's profile

Madmark2

1254 posts in 1317 days


#6 posted 04-05-2020 04:37 PM

Twist lock connectors. SJ wire pendants. Drops anywhere & move anytime.

-- The hump with the stump and the pump!

View ibewjon's profile

ibewjon

1506 posts in 3522 days


#7 posted 04-05-2020 04:44 PM

Since you will have cords dropping to the floor to feed the tools, run the strut to the floor and anchor it there with a strut L fitting. No movement to worry about. Steel purlins or wood trusses overhead? There are clamps to hold the strut to steel purlins, or bolt it to the wood.

View GrantA's profile

GrantA

2411 posts in 2137 days


#8 posted 04-05-2020 05:16 PM

I’m setting up a shop as well and was fortunate to score some nice stands to secure to the floor next to machines. Disconnect mounted to the stand, conduit to the disconnect from overhead. I’ll get some pics in the next day or two when I get back there.

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Steinbierz

99 posts in 866 days


#9 posted 04-05-2020 05:43 PM


Since you will have cords dropping to the floor to feed the tools, run the strut to the floor and anchor it there with a strut L fitting. No movement to worry about. Steel purlins or wood trusses overhead? There are clamps to hold the strut to steel purlins, or bolt it to the wood.

- ibewjon

Mine are all steel z-purlins. I thought about running it all the way to the floor…to do that though I would either have to source some longer channel than 10’ or fasten some sections together.

-- Larry ~ Alvin, TX (Home of Nolan Ryan)

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Steinbierz

99 posts in 866 days


#10 posted 04-05-2020 06:00 PM



1) They make purlin clamps that hold threaded down rods. No need to drill holes, drilling not recommended in thin gauge purlin s either.

I am not a structural engineer so can’t dispute your point. I will say though that I have read on multiple forums that drilling through the web of a purlin is seldom an issue as long as you aren’t hogging out big holes. The arguments always seem to be more about how much unsupported weight you can free-hang from a purlin.

-- Larry ~ Alvin, TX (Home of Nolan Ryan)

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ibewjon

1506 posts in 3522 days


#11 posted 04-05-2020 06:11 PM

There are many types of splice plates available. I would use 4 hole, 2 bolts into each strut. 20’ strut is commonly available at an electrical supply or Fastenal if you have a way to haul it. There are u bolt clamps for strut to hold to your purlins, the bolts are not a normal U, they are square cornered u bolts. The bent leg of the plate hooks over the bottom lip of the purlin.

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Steinbierz

99 posts in 866 days


#12 posted 04-05-2020 06:12 PM



I m setting up a shop as well and was fortunate to score some nice stands to secure to the floor next to machines. Disconnect mounted to the stand, conduit to the disconnect from overhead. I ll get some pics in the next day or two when I get back there.

- GrantA

I look forward to seeing the pictures you post!

-- Larry ~ Alvin, TX (Home of Nolan Ryan)

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Steinbierz

99 posts in 866 days


#13 posted 04-05-2020 06:17 PM



There are many types of splice plates available. I would use 4 hole, 2 bolts into each strut. 20 strut is commonly available at an electrical supply or Fastenal if you have a way to haul it. There are u bolt clamps for strut to hold to your purlins, the bolts are not a normal U, they are square cornered u bolts.

- ibewjon

I live in a smaller town but we do have one electrical supply house and a Fastenal…I’ll have to give them a call to see if they are open given the current environment and if they have the longer struts. I am starting to weigh what projects I can complete with materials on hand so I can limit the trips I make away from the house.


-- Larry ~ Alvin, TX (Home of Nolan Ryan)

View Jim Finn's profile (online now)

Jim Finn

2826 posts in 3651 days


#14 posted 04-05-2020 06:39 PM

I am a retired sheet metal worker and we used miles of unistrut or superstrut to hang our duct and to build walls in clean rooms There is a strut that is painted green out there also. If I did not want to extend the strut to the floor I would run two of them down six inches apart with cross struts and mount the conduit to that assembly. Would keep it pretty rigid.

-- No PHD just a DD214 Lubbock Texas

View CaptainKlutz's profile

CaptainKlutz

2987 posts in 2224 days


#15 posted 04-05-2020 09:33 PM

I am a retired sheet metal worker and we used miles of unistrut or superstrut to hang our duct and to build walls in clean rooms There is a strut that is painted green out there also. If I did not want to extend the strut to the floor I would run two of them down six inches apart with cross struts and mount the conduit to that assembly. Would keep it pretty rigid.

- Jim Finn

+1 Running 2 rails makes for solid/permanent installation that will take a lot more abuse, then a single rail. running two rails to floor is sort of industrial standard method of mounting disconnect switches, remote breaker panels, or outlets in open industrial spaces.

+1 There are generic green struts and there is Unistrut. There is difference. Can even get stainless steel Unistrut, when you need it. The cheapest green stuff is thinner 14awg steel and may not fit real Unistrut accessories. Shop carefully if you can’t find an industrial supplier in your area.

-- If it wasn't for bad luck, I wouldn't have no luck at all, - Albert King - Born Under a Bad Sign released 1967

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