[RE-wrenches] Concrete tight versus raintight

[August Goers]

Hi William,



This has also been a longstanding problem for us – and one that we don’t
have a good solution for. Technically speaking we’re supposed to use the
listed fitting with all the parts that come with it. However, the rubber
gaskets between the connector and box cause issues with tightening as you
mention below and also crack over time. Some inspectors don’t want us using
the gaskets at all. I like your idea about using the Arlington
yellow-colored gaskets. They are nice a solid. We’ve been putting a good
quality clear sealant around all of our outdoor fittings for a while now
and it seems to have stopped most of the water intrusion into the conduit.
We also drill drip holes in boxes where we feel there is a good chance that
moisture will enter. This is also a contentious decision as technically the
listed outdoor box shouldn’t have holes drilled in it…



Best, August



*From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *William Miller
*Sent:* Thursday, January 16, 2014 11:54 AM
*To:* 'RE-wrenches'
*Subject:* Re: [RE-wrenches] Concrete tight versus raintight



Friends:



We used some Bridgeport fittings yesterday.  My foreman reports the
following:



*The new blue rain tite connectors have a prob. The connectors have a
plastic gasket/ring that seals between the connector body and the box. It
is impossible to tighten the con to box without destroying the ring or
having a slightly loose con/box connection. A loose connection means poor
bonding. *



I would add that any looseness of these fittings can contribute to
mechanical failure of conduit runs.  We rely on code compliant strapping *
*and** secure tightening of fittings to keep a conduit assembly secure and
in place for years to come.  It looks like we need to find a fitting with
firmer washers.  The Arlington NMLT fittings have yellow washers that are
pretty rigid.  I will rob one and try it on the Bridgeports.  We bought a
quantity of the EMT fittings and I don’t want to have to replace them…



William







*From:* re-wrenches-bounces at lists.re-wrenches.org [
mailto:re-wrenches-bounces at lists.re-wrenches.org<re-wrenches-bounces at lists.re-wrenches.org>]
*On Behalf Of *August Goers
*Sent:* Thursday, January 16, 2014 8:00 AM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Concrete tight versus raintight



Hi William,



About 5 years ago this became a big issue up in San Francisco and we had to
learn the hard way. We used to just go buy outdoor EMT fittings and we were
okay, then the inspectors started requiring fittings that say raintight or
wet location (often stamped “wetloc”) on them. I don’t know for certain,
but I believe it might have been a clarification added in the 2008 NEC at
the time. See “NEC 358.42 Couplings and Connectors. Couplings and
connectors used with EMT shall be made up tight. Where buried in masonry or
concrete, they shall be concretetight type. Where installed in wet
locations, they shall comply with 314.15.”



If you go over to NEC 314.15 they mention that fittings installed in wet
locations shall be listed for use in wet locations.



So, you just need to make sure that the fittings you get are listed for the
correct purpose. I have seen both concretetight and wetloc type. As someone
else mentioned, most of the wetloc fittings have a plastic sealing ring in
them and many or blue colored.



Best,



August

Luminalt



*From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *William Miller
*Sent:* Wednesday, January 15, 2014 10:32 PM
*To:* RE-wrenches
*Subject:* [RE-wrenches] Concrete tight versus raintight



Friends:



It appears I may have a whole in my education.  I thought all EMT
compression fittings were alike.  It appears that I have been using
“concrete tight” fittings where I should have been using “raintight”
fittings.  Did they use to be the same item?  I did a web search on the
differences and came up empty.  I want to be informed in this area and
appreciate any knowledge.



William Miller





[image: Gradient Cap]

Lic 773985

millersolar.com <http://www.millersolar.com/>

805-438-5600


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