The hospital we are working on is built on isolators that allow the building to move 30" in any direction, 5'-0" overall. We have flex from the ground to the building and the shortest we can make the flex between supports to allow this movement is 9'-0". We are unable to find an exception in the CEC/NEC for this condition and the IOR has turned down our inspection. Any help would be appreciated.
9ft Flex Support Variance?
- Thread starter tldouglas
- Start date
- Status
- Location
- Simi Valley, CA
I don't think you'll find an exception.
If you are looking in the CEC I assume that you are in CA and since you are doing a hospital I know that you are dealing with the state.
I would think that it's up to you or the engineer to show the inspector that it is allowed.
Since we don't do hospitals at the local levels here, I don't know much about them, but I'm guessing that they are not required to have that much movement and if they are then it should be addressed somewhere in one or all of the codes.
If you are looking in the CEC I assume that you are in CA and since you are doing a hospital I know that you are dealing with the state.
I would think that it's up to you or the engineer to show the inspector that it is allowed.
Since we don't do hospitals at the local levels here, I don't know much about them, but I'm guessing that they are not required to have that much movement and if they are then it should be addressed somewhere in one or all of the codes.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
TL, welcome to the forum! 
You're caught between conflicting requirements. There should be a way to "introduce" Rule A Enforcer to Rule B Enforcer and let them hash it out.
This can't be the first time this situation has popped up, unless these are new requirements. How was it resolved before? Can you find a similar install?
You're caught between conflicting requirements. There should be a way to "introduce" Rule A Enforcer to Rule B Enforcer and let them hash it out.
This can't be the first time this situation has popped up, unless these are new requirements. How was it resolved before? Can you find a similar install?
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
It should be possible to design a support that would allow the necessary flexibility during an earthquake. I would think that this would be the responsibility of the isolation system designer.
For example, you could use something strong enough to hold the weight of the flex, but weak enough to break away during an earthquake. Or a flexible support with enough elasticity to allow the necessary movement. Or a support that is fixed vertically but can move in the horizontal plane .
Cheers, Wayne
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Yeah. Unistrut straps with built-in rollers that traverse the strut channel.
- Location
- Simi Valley, CA
Larry, you draw that, I'll find someone to build it and you and I are outta here! Partner.
Partner.
- Location
- Massachusetts
Big cords
- Location
- Simi Valley, CA
I actually thought of that. Hard to answer without seeing the actual install.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Use 'energy chain' for the support? These are the 'roller chain' like guides used on some heavy equipment to protect hydraulic hoses and the like.
-Jon
-Jon
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Just remember your first signature line when it's time to distribute the royalties . . . partner.Larry, you draw that, I'll find someone to build it and you and I are outta here!
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Okay, I've drawn a roller bracket for mounting a second piece of strut (which holds the raceway with the usual hardware) in front of the wall-mounted piece.
It can be made as either one or two separate pieces, so any length of strut can be used between them, for more than one raceway or raceways of different sizes.
It inserts into a piece of strut as easily as any standard 2-piece strut strap does. Where do I send my submission (besides registered to myself and my lawyer?)
It can be made as either one or two separate pieces, so any length of strut can be used between them, for more than one raceway or raceways of different sizes.
It inserts into a piece of strut as easily as any standard 2-piece strut strap does. Where do I send my submission (besides registered to myself and my lawyer?)
ive got a price sheet showing 5 conductor 4/0 type W cord (i dont think I would like having to wind up a piece of that....) they also have 4 conductor 500mcm type W cord, but no 5C/500.
9ft flex clarified
9ft flex clarified
Thanks for your comments. We are design assist so they have asked for our help. We've checked simular projects and they have either not had to support the flex or the EOR designed a non-listed assembly not allowed on this project.
Maybe if I am more clear, some of your ideas are clever. The flex attaches to the floor horizontally and to the deck 6ft above vertically. The flex is shaped like a goose neck to allow the movement to and from the floor attachment and the flex needs to move 360 degrees. As the building moves toward or away the center of the flex moves up as well as side to side in the direction the building is moving. The supports need to move on the horizontal and vertical plane. A cable on a pulley with a counterweight per conduit would phyically work however it's not listed.
Thanks
9ft flex clarified
Thanks for your comments. We are design assist so they have asked for our help. We've checked simular projects and they have either not had to support the flex or the EOR designed a non-listed assembly not allowed on this project.
Maybe if I am more clear, some of your ideas are clever. The flex attaches to the floor horizontally and to the deck 6ft above vertically. The flex is shaped like a goose neck to allow the movement to and from the floor attachment and the flex needs to move 360 degrees. As the building moves toward or away the center of the flex moves up as well as side to side in the direction the building is moving. The supports need to move on the horizontal and vertical plane. A cable on a pulley with a counterweight per conduit would phyically work however it's not listed.
Thanks
Two struts mount to ceiling, spaced apart just enough for a third strut to catch one side
of each, facing upside down. The grooves that hold 'straps' in will lock into each other and
slide very easy. I've made tool drawers like this and it handles the weight just fine.
Example from one manufacturer.
However, I have not seen any energy chain which permits 3-axis movement. It permits considerable one-axis movement. Two-axis movement is severely limited compared to one-axis. And three-axis is ??? Note the linked page mentions rotary near bottom right.
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