Discussion:
Electrical: conduit beneath slab?
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Les
2006-06-20 02:12:07 UTC
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I will be running some electrical beneath the slab in a house primarily constructed of concrete. In the past, I've seen the electrical-grade pvc used as conduit for electrical running beneath a slab. I was wondering if there's any kind of more flexible material that can be used beneath a slab.



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Engnrguy
2006-06-20 14:12:06 UTC
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Post by Les
I will be running some electrical beneath the slab in a house primarily constructed of concrete. In the past, I've seen the electrical-grade pvc used as conduit for electrical running beneath a slab. I was wondering if there's any kind of more flexible material that can be used beneath a slab.
There are plenty of options. Liquid tight (Flexible metal conduit
encassed in a rubber or pvc jacket), regular flexible metal conduit,
etc. BUT the code will dictate what you can and can't put in concrete.
I would look at how flexible it needs to be, pick a couple of options
then get a code book and look up each option.

Unless of course your not getting it inspected, which I don't recommend
you do.
SteveF
2006-06-20 15:36:03 UTC
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Post by Engnrguy
Post by Les
I will be running some electrical beneath the slab in a house primarily
constructed of concrete. In the past, I've seen the electrical-grade pvc
used as conduit for electrical running beneath a slab. I was wondering
if there's any kind of more flexible material that can be used beneath a
slab.
There are plenty of options. Liquid tight (Flexible metal conduit
encassed in a rubber or pvc jacket), regular flexible metal conduit,
etc. BUT the code will dictate what you can and can't put in concrete.
I would look at how flexible it needs to be, pick a couple of options
then get a code book and look up each option.
Unless of course your not getting it inspected, which I don't recommend
you do.
Unfortunately the NEC tends to have things like Article 356 on Liquidtight
flexible nonmetallic conduit which says under installation (Art 356.10
4)) - LFNC shall be permitted to be used for direct burial where listed
and marked for that purpose.

Which doesn't tell you much.

Les - you need to get with your electrician or go down to the Inspections
department and talk to the electrical inspector about what you want to do
and let them tell you how to best handle it. I've put a couple runs under a
slab and always used the gray electrical conduit.

Steve.
Engnrguy
2006-06-20 16:46:26 UTC
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Post by SteveF
Unfortunately the NEC tends to have things like Article 356 on Liquidtight
flexible nonmetallic conduit which says under installation (Art 356.10
4)) - LFNC shall be permitted to be used for direct burial where listed
and marked for that purpose.
Typically the NEC defines terms like direct burial or refers to what
they mean when they mention it. Direct burial typically refers to just
digging a hole and tossing it in. Under a concrete slab would also be
listed seperately in that fashion, "under a concrete slab"
Post by SteveF
Les - you need to get with your electrician or go down to the Inspections
department and talk to the electrical inspector about what you want to do
and let them tell you how to best handle it. I've put a couple runs under a
slab and always used the gray electrical conduit.
Good idea. Call a pro or talk to the inspector and he can answer your
question. PVC conduit is a sure bet. Schedule 80 versus schedule 40 is
always a safe bet regardless.
chuckster
2006-06-20 22:13:41 UTC
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Carlon ENT is approved for slab work. go to www.carlon.com and view
the ENT products.
Post by Les
I will be running some electrical beneath the slab in a house primarily constructed of concrete. In the past, I've seen the electrical-grade pvc used as conduit for electrical running beneath a slab. I was wondering if there's any kind of more flexible material that can be used beneath a slab.
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