Core/Chop

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
These conduits are going vertically in an existing stairwell. TO include a core drill for each conduit will probably not be what is done I'm thinking. I believe chopping a slot would be more efficient. I'm referring to when there are 3+ conduit next to each other. No?


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Also, I know it's a dumb question but panel DP-EH4 is rated 480v and fed from DP-EH1 208v panel. There is no xfrmr. Can a 480v panel be fed from 208v source without a transformer?
 
These conduits are going vertically in an existing stairwell. TO include a core drill for each conduit will probably not be what is done I'm thinking. I believe chopping a slot would be more efficient. I'm referring to when there are 3+ conduit next to each other. No?


View attachment 2580680
As is often the case, there could be so many more things to consider here. In some cases I have informed you that we need more information, but here I think it would be hard to. My first thought here is questioning whether this stairwell is subject to the rule that only conduits associated with the stairwell are allowed in it. I bet it is. Second, are the walls you want to core fire walls? Do you need to be concerned with drilling through rebar? Then, if firewall, then what assembly do you want to use to seal? That is a start anyway.
These conduits are going vertically in an existing stairwell. TO include a core drill for each conduit will probably not be what is done I'm thinking. I believe chopping a slot would be more efficient. I'm referring to when there are 3+ conduit next to each other. No?


View attachment 2580680
As is often the case, there could be so many more things to consider here. In some cases I have informed you that we need more information, but here I think it would be hard to. My first thought here is questioning whether this stairwell is subject to the rule that only conduits associated with the stairwell are allowed in it. I bet it is. If so, then the gallery spaces must be integral with the stairwell, or the entire installation is illegal. Second, are the walls you want to core fire walls? Do you need to be concerned with drilling through rebar? Then, if firewall, then what assembly do you want to use to seal? That is a start anyway.
 
Is this a fire rated stairwell ?? (Post overlapped stratheads...same concern when you mentioned stairwell)
 
Is this a fire rated stairwell ?? (Post overlapped stratheads...same concern when you mentioned stairwell)
We've run vertical risers in stairwells before. They typically get a 2 hour finish installed over them.
 
As is often the case, there could be so many more things to consider here. In some cases I have informed you that we need more information, but here I think it would be hard to. My first thought here is questioning whether this stairwell is subject to the rule that only conduits associated with the stairwell are allowed in it. I bet it is. Second, are the walls you want to core fire walls? Do you need to be concerned with drilling through rebar? Then, if firewall, then what assembly do you want to use to seal? That is a start anyway.

As is often the case, there could be so many more things to consider here. In some cases I have informed you that we need more information, but here I think it would be hard to. My first thought here is questioning whether this stairwell is subject to the rule that only conduits associated with the stairwell are allowed in it. I bet it is. If so, then the gallery spaces must be integral with the stairwell, or the entire installation is illegal. Second, are the walls you want to core fire walls? Do you need to be concerned with drilling through rebar? Then, if firewall, then what assembly do you want to use to seal? That is a start anyway.
How would I know if that rule applies? I am excluding and scanning or xray, will be done by others. Wall are fire rated and will look in spec as to what is needed. Probably 3M fire caulking.
 
How would I know if that rule applies? I am excluding and scanning or xray, will be done by others. Wall are fire rated and will look in spec as to what is needed. Probably 3M fire caulking.
The building code may limit what type of vertical risers that can be run in a stairwell. The electrical code doesn't care. We would core drill our holes, run the risers, and then the carpenter would box it in with a 2 hour rated wall.
 
The electrical code doesn't care.
It does starting with the 2020 code.
(2023 code) 300.25 Exit Enclosures (Stair Towers).
Where an exit enclosure is required to have a fire resistance rating, only electrical wiring methods serving equipment permitted by the authority having jurisdiction in the exit enclosure shall be installed within the exit enclosure.

Exception:
Where egress lighting is required on outside exterior doorways from the exit enclosure, luminaires shall be permitted to be supplied from the inside of the exit enclosure.
 
Good to know, the OP is on the 2008. Also if it's behind a 2 hour wall is it actually in the stairwell?
No idea...I would expect that most of the time the stair is designed to the minimum possible dimensions, so if that would be the case, there would be no room for a wall.
 
No idea...I would expect that most of the time the stair is designed to the minimum possible dimensions, so if that would be the case, there would be no room for a wall.
I agree. We've run risers in stairwells in old buildings but the minimum egress clearances had to be met after the conduits were enclosed.
 
How would I know if that rule applies? I am excluding and scanning or xray, will be done by others. Wall are fire rated and will look in spec as to what is needed. Probably 3M fire caulking.
I am not picking on you. I would like to give you advice, regularly. That said, I often don't know where you question is coming from. I think it is from the perspective of the estimator. If so, my advice is don't worry about what isn't on the plans. If as, I think we have determined, the stairwell is enclosed in a fire barrier, either include money for fire caulking or exclude in your proposal. I am surprised you would exclude fire coring and x-ray, I would assume, unless there are multiple systems penetrating these walls the CM would want you to carry those costs. Regarding the "no conduit in a stairwell" that is a perfect opportunity for a change order, unless politically it is better for you to have the owner's of the CM's back. This is all about strategy. Back to the other, if you are estimating, just figure on coring each hole, and including mineral wook and fire caulk for each penetration
How would I know if that rule applies? I am excluding and scanning or xray, will be done by others. Wall are fire rated and will look in spec as to what is needed. Probably 3M fire caulking.
I am not picking on you. I would like to give you advice, regularly. That said, I often don't know where you question is coming from. I think it is from the perspective of the estimator. If so, my advice is don't worry about what isn't on the plans. If as, I think we have determined, the stairwell is enclosed in a fire barrier, either include money for fire caulking or exclude in your proposal. I am surprised you would exclude fire coring and x-ray, I would assume, unless there are multiple systems penetrating these walls the CM would want you to carry those costs. Regarding the "no conduit in a stairwell" that is a perfect opportunity for a change order, unless politically it is better for you to have the owner's of the CM's back. This is all about strategy. Back to the other, if you are estimating, just figure on coring each hole, and including mineral wool and fire caulk for each penetration. If you installation team comes up with a cheaper way, it will offset the cost of somewhere that you underestimated.
 
I am not picking on you. I would like to give you advice, regularly. That said, I often don't know where you question is coming from. I think it is from the perspective of the estimator. If so, my advice is don't worry about what isn't on the plans. If as, I think we have determined, the stairwell is enclosed in a fire barrier, either include money for fire caulking or exclude in your proposal. I am surprised you would exclude fire coring and x-ray, I would assume, unless there are multiple systems penetrating these walls the CM would want you to carry those costs. Regarding the "no conduit in a stairwell" that is a perfect opportunity for a change order, unless politically it is better for you to have the owner's of the CM's back. This is all about strategy. Back to the other, if you are estimating, just figure on coring each hole, and including mineral wook and fire caulk for each penetration

I am not picking on you. I would like to give you advice, regularly. That said, I often don't know where you question is coming from. I think it is from the perspective of the estimator. If so, my advice is don't worry about what isn't on the plans. If as, I think we have determined, the stairwell is enclosed in a fire barrier, either include money for fire caulking or exclude in your proposal. I am surprised you would exclude fire coring and x-ray, I would assume, unless there are multiple systems penetrating these walls the CM would want you to carry those costs. Regarding the "no conduit in a stairwell" that is a perfect opportunity for a change order, unless politically it is better for you to have the owner's of the CM's back. This is all about strategy. Back to the other, if you are estimating, just figure on coring each hole, and including mineral wool and fire caulk for each penetration. If you installation team comes up with a cheaper way, it will offset the cost of somewhere that you underestimated.
Thank you!!!
 
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