Running conduit across the floor?

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Old 12-23-07, 10:37 PM
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Running conduit across the floor?

As I stated in an earlier post (Question regarding distribution load & balancing ), I need to install a vehicle lift in a utility space. The space (and the lift) will be used primarily for vehicle storage.

The lift is a four post system with an electro-hydraulic power unit mounted on the side of one of the posts. For operator ease-of-use, the power unit (which also houses the lift controls) should be mounted on one of the lift's front posts (i.e., farthest from the back wall where the electrical service is located).

My question is, what would be the best (and code-compliant) way of getting electrical service from the back wall of the space to the front lift post where the power unit is to be mounted (approx 18 feet from the back wall)? Since the concrete slab is already poured, I cannot come up from underground.

So should I run conduit across the surface of the floor? The three problems that come to mind: (1) ensuring the conduit is waterproof; (2) ensuring the conduit is not damaged; and (3) dealing with the tripping hazard (although I don't expect much foot traffic between the front of the lift and the back wall). I assume I will need to use rigid conduit for this purpose and I assume the threaded fittings can be waterproofed.

And advice or tips would be appreciated (including the best sealant to use for waterproofing the conduit).
 
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Old 12-23-07, 11:10 PM
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Originally Posted by SpyGuy View Post
As I stated in an earlier post (Question regarding distribution load & balancing ), I need to install a vehicle lift in a utility space. The space (and the lift) will be used primarily for vehicle storage.

The lift is a four post system with an electro-hydraulic power unit mounted on the side of one of the posts. For operator ease-of-use, the power unit (which also houses the lift controls) should be mounted on one of the lift's front posts (i.e., farthest from the back wall where the electrical service is located).

My question is, what would be the best (and code-compliant) way of getting electrical service from the back wall of the space to the front lift post where the power unit is to be mounted (approx 18 feet from the back wall)? Since the concrete slab is already poured, I cannot come up from underground.

So should I run conduit across the surface of the floor? The three problems that come to mind: (1) ensuring the conduit is waterproof; (2) ensuring the conduit is not damaged; and (3) dealing with the tripping hazard (although I don't expect much foot traffic between the front of the lift and the back wall). I assume I will need to use rigid conduit for this purpose and I assume the threaded fittings can be waterproofed.

And advice or tips would be appreciated (including the best sealant to use for waterproofing the conduit).

do you have a roof over this one ?

if so run the EMT conduct or PVC condut on the roof rafters above then run them down to the pump motor control panel.

[ 1/2 inch size will be plenty big for #10 wires you are running in there you will need black and red and green THHN/THWN wires for this.]

if no roof this what i will do this but i personally dont like to do this but run half inch rigid conduct on the floor and snake up.

or other option is notch the floor with floor cutting tool then you can drop the rigid or sch. 80 PVC pipe and stubbed up from floor and that will almost complety elmated the trip hazarous.

[ this is common we do that with commercal area But IMO i rather run above if possible .]

Merci, Marc
 
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Old 12-24-07, 01:14 AM
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Thanks again Marc for your assistance.

Originally Posted by french277V View Post
do you have a roof over this one ? if so run the EMT conduct or PVC condut on the roof rafters above then run them down to the pump motor control panel.
Yes, there the building is fully enclosed. Actually, I considered this option, but it's a very high-ceiling (20 feet). So I'd be looking at a 16 foot drop from the rafter to the top of the lift post. I don't know how to do this and still be code-compliant. (It's my understanding that the NEC stipulates the maximum support spacing for EMT is 10 feet.)

This would certainly be the best solution if it's possible.

Originally Posted by french277V View Post
[ 1/2 inch size will be plenty big for #10 wires you are running in there you will need black and red and green THHN/THWN wires for this.]
Yup, that's my plan.

Originally Posted by french277V View Post
if no roof this what i will do this but i personally dont like to do this but run half inch rigid conduct on the floor and snake up.
So if the ceiling drop is not an option, then it seems to me that rigid conduit on the floor is the only other option. I would actually install a vertical run of rigid conduit down the back wall of the building, across the floor parallel to the lift (as close to the lift's mounting post pads as possible), and then up the lift post to a junction box for the lift's power unit connection. That way the rigid conduit forms a water-proof "U".

Originally Posted by french277V View Post
or other option is notch the floor with floor cutting tool then you can drop the rigid or sch. 80 PVC pipe and stubbed up from floor and that will almost complety elmated the trip hazarous.
I'd rather not chop up the floor. If the lift were being installed as part of an auto service or repair shop, then I could make a strong case for cutting the slab and burying the conduit. But as I mentioned, the primary purpose of the lift (and the space) is for long-term vehicle storage. So I think the trip hazard might be an acceptable risk in this situation. But I'm welcome to other opinions (especially if there's some kind of OSHA rule that might get us in trouble).
 
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Old 12-24-07, 02:04 AM
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If this is a commercail building you going have to stop right here and get the electrician [ see the other thread on that info ]


sorry about that but i have to do the right thing to play it safe

Merci, Marc
 
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Old 12-24-07, 06:08 AM
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Come from Above

Our Central Fleet shop at work have the same type of lifts with ceilings as high or higher. They come down from the ceiling with conduit to power the lifts.
 
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Old 12-24-07, 07:42 AM
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this area may be classified a "hazardous location" and would need to be wired in accordance with that section of the NEC

consult a qualified electrician or your local inspector on proper wiring installation.
 
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Old 12-25-07, 04:43 AM
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Originally Posted by sgtgerryf View Post
Our Central Fleet shop at work have the same type of lifts with ceilings as high or higher. They come down from the ceiling with conduit to power the lifts.
Can you tell me what type of conduit is used for the vertical drops? I would think EMT is not strong enough (and then there's that requirement for support of EMT every 10 feet). So would rigid metal conduit be the way to do this?

Another consideration is that the lift requires compressed air (for releasing the safety locks). So if I were going to install vertical drops for the power, I would also have to route airlines up a wall to the ceiling, across the roof, and down to the lift's post-mounted power unit. Seems like a lot of labor & materials for a lift and space which are primarily intended for vehicle storage.

The more I think about this, the more inclined I am to run rigid conduit across the floor for the power, with parallel rigid plumbing for the compressed air. Perhaps a steel channel should be secured over the pipes on the floor to protect against any accidental damage. It can be painted a bright color to help mitigate any tripping hazard.
 
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Old 12-25-07, 08:15 AM
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If you don't pull a permit and get an inspection on this... You can end up not being covered for loss from your insurance company.


If you are going to spring for the cost of the lift, you should apply for the permits and do the job right.
 
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Old 12-25-07, 09:26 AM
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i'd use unistrut

from the ceiling as the structure, all the way to the floor. Run EMT and 1/2" or so copper tubing for the air, NOT PVC.
 
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Old 12-25-07, 02:15 PM
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Originally Posted by brewaholic View Post
If you don't pull a permit and get an inspection on this... You can end up not being covered for loss from your insurance company.
We will get a permit & an inspection. I just wanted to get some informed advice during the planning stage. Thanks.
 
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Old 12-25-07, 02:39 PM
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You can run the pipe and conduit on the floor and then build "speed bumps" over it with mortar, sand mix, topping mix or one of several mastic products.

If you seal the floor well before applying the speed bump it will break away from the sealed floor when you want to remove the piping and conduit.
 
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Old 12-25-07, 02:59 PM
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Originally Posted by telecom guy View Post
i'd use unistrut from the ceiling as the structure, all the way to the floor.
That may be a good solution, although it will add significantly to the cost of the project (both materials & labor). Would you recommend running the conduit & plumbing inside the channel of the unistrut for protection (perhaps using back-to-back unistrut)?

Originally Posted by telecom guy View Post
Run EMT and 1/2" or so copper tubing for the air, NOT PVC.
I never use PVC for shop compressed air (although I've seen it used and it makes me cringe: if the PVC fails it can explode, sending shrapnel in all directions). I always use Type L copper drawn temper tube for its safety, strength, and ability to withstand corrosion.
 
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