Pulling Wire in ENT before concrete is poured

[ThreeTenFifteen]

Hello forum friends!
I'm looking at a mass timber project that consists of cross laminated timber with a 5" topping slab on each floor. I got into a discussion with a few co-workers about pulling wire in the ENT after rebar is dropped but before the concrete is poured. The reason for doing this would be to prevent having to coordinate wire pulling to light fixture outlets on the floor below, and also to ensure that there isn't any challenges with wire pulling after concrete is poured. Article 300.18(A) talks about runs needing to be complete before the installation of conductors. My thoughts are doing this is code compliant so long as the ENT is supported as required in 362.30 and terminated at both ends. I am curious if anyone has a different understanding on this? Or if there's anything to be mindful of if we decide to go this direction?

Thanks!

 

[kwired]

Pulling conductors before concrete is totally your call and you may have good and bad reasons either way on this.

Do make sure your ENT is secured well enough and often enough so that it won't float to the top of the concrete when they pour.

Pulling likely will be somewhat easier once embedded as the ENT will not have any flex to it in the slab anymore this presumes nothing was damaged after you installed it and up to the pour, though that could be a problem even if you have already pulled conductors as well.

 

[don_resqcapt19]

I can't imagine using ENT in a floor pour around here. The way the concrete is installed here, none of the ENT would survive....they must pour concrete differently in other parts of the country.

 

[ThreeTenFifteen]

I can't imagine using ENT in a floor pour around here. The way the concrete is installed here, none of the ENT would survive....they must pour concrete differently in other parts of the country.

Are you primarily worried about the rodbusters or the concrete finishers? I've had some dealings with the rodbusters for sure but once the rebar is down the concrete guys typically do a good job at staying on top of the bar and off the smurf tube. Regardless, I always have a few people on standby with parts to do a quick fix if needed.

Pulling conductors before concrete is totally your call and you may have good and bad reasons either way on this.

Do make sure your ENT is secured well enough and often enough so that it won't float to the top of the concrete when they pour.

Pulling likely will be somewhat easier once embedded as the ENT will not have any flex to it in the slab anymore this presumes nothing was damaged after you installed it and up to the pour, though that could be a problem even if you have already pulled conductors as well.

Thanks for the tips -
More than likely I will pull conductors to the lighting outlets and if that proves to be more difficult or unreliable I'll make some adjustments.

Appreciate the input!

 

[Fred B]

Runs to be completed is only referencing the Conduit not the conductor installation. Personally I wouldn't be putting in the wire until after the pour is completed, and would cap off all conduit openings until after the pour to prevent unintentional concrete entry into the conduit. (seen is happen)

Just make sure of all your locations for penetrations, that they match to wall placement and any other locations wiring would be needed prior to pour as it would be exceptionally difficult to make a change after the pour is completed. For ceiling penetrations below the pour still wouldn't usually add the conductors until the concrete work is complete, dripping past the penetration is not unheard of (seen it) and don't want that on the wire.

 

[don_resqcapt19]

Are you primarily worried about the rodbusters or the concrete finishers? I've had some dealings with the rodbusters for sure but once the rebar is down the concrete guys typically do a good job at staying on top of the bar and off the smurf tube. Regardless, I always have a few people on standby with parts to do a quick fix if needed.

Thanks for the tips -
More than likely I will pull conductors to the lighting outlets and if that proves to be more difficult or unreliable I'll make some adjustments.

Appreciate the input!

Have never used ENT in a pour but have had them break couplings apart in EMT in pours. A couple of the projects around here, the engineered design required RMC for that reason.