NM cable and the outdoors

[electrofelon]

Seems to be consensus so far. My question then -

What use are raintite fittings for EMT and the like? They serve no purpose whatsoever other than to increase the cost of the installation.

Exactly. That is my big issue with them. Seems to serve no purpose. We already have to use wet rated wire, and there are other requirements such as raceway allowed to drain etc. Finally, IMO raintight fittings are not manufactured with enough quality to keep water out anyway. Just went back to a roof I did a year ago to make a few changes, some of the rain tight runs were filled with water. Its DUMB. So much hate and anger!

Edit: sorry to turn this into a rant against RT fittings, but anyone know offhand how that change came about? What was the justification? Is it something manufacturers made before the code requirement came in?

 

[Ponchik]

Seems to be consensus so far. My question then -

What use are raintite fittings for EMT and the like? They serve no purpose whatsoever other than to increase the cost of the installation.

Exactly!!!
manufacturers get involved with the CMP and the NEC allowing it.

 

[Nuber]

Personally I think it's fine to bring NM through an exterior wall so long as it comes immediately into a box where it it's spliced to transition to another wiring method. Doesn't matter if the box is recessed or not. Boxes are not wiring methods. One could quibble and argue the exact wording, to be sure, but the argument against is not that reasonable. In my opinion.

My guess as to the theory opposed -

Exterior items such as panels need to have a gap between the wall and the enclosure. 312.2 Therefore installing NM from the wall to the enclosure would expose the cable to exterior conditions - meaning damp or wet - a violation.

As cables must be secured to the enclosure 312.5(C) - there is really no code compliant way to ensure that the NM is not exposed for that gap between the wall and the enclosure.

I have been violating this particular interpretation of the code for my entire career, and haven't been called on it once.

 

[Nuber]

Exactly. That is my big issue with them. Seems to serve no purpose. We already have to use wet rated wire, and there are other requirements such as raceway allowed to drain etc. Finally, IMO raintight fittings are not manufactured with enough quality to keep water out anyway. Just went back to a roof I did a year ago to make a few changes, some of the rain tight runs were filled with water. Its DUMB. So much hate and anger!

Edit: sorry to turn this into a rant against RT fittings, but anyone know offhand how that change came about? What was the justification? Is it something manufacturers made before the code requirement came in?

Around my neck of the woods inspectors started busting contractors for not using RT fittings when they first came out. I had a discussion with a state guy and he was of the opinion (as am I) that usage of such fittings made the interior of the raceway a dry location. Prior to that time compression fittings were only damp location rated (as they are now) - thus the interior of the raceway needed a wet/damp location wiring method.

As noted - 300.9 completely shreds this notion leading me to agree with the ongoing theory that manufacturers convince inspectors and CMP's that their products are needed - even when they are not. Thus improving their sales.

I support your rant against RT fittings.

 

[don_resqcapt19]

I agree with the NM cable and the THHN conductors not allowed in wet location, and the AHJ has every right to dissect the OP installation and decide whether or not it is compliant.

But, there is always a but, IMO this is what happens when manufacturer greedy reps get involved with the CMP. and push different product in place of the existing one that has been working well over 30 years without any issues.

Like the NM cable that has been fine for outdoors for many years and now (well it is has been for a while) it is a hazard. I guess if I was the manufacturer I may do the same thing because it is about the Benjamins.

It could also be that the manufacturing process and material that was available 30 years ago that allowed construction of the NM cable is not available anymore, hence the new product and the NEC change. I don't know.

The manufacturers had nothing to do with 300.9. 300.9 was a code change proposal of mine to clear up the question as to whether the inside of a raceway installed in a wet location is also a wet location. CMP-3 acted on my proposal and said that the inside of such a raceway is indeed a wet location.

 

[Ponchik]

The manufacturers had nothing to do with 300.9. 300.9 was a code change proposal of mine to clear up the question as to whether the inside of a raceway installed in a wet location is also a wet location. CMP-3 acted on my proposal and said that the inside of such a raceway is indeed a wet location.

Your proposal was only to clarify if the interior was dry or wet. You probably were not involved with the manufacturers pushing a product that is not necessary.

 

[LarryFine]

I tell people that inside a conduit is not a location; the wires are in whatever location the conduit is.

 

[JohnE]

Seems to be consensus so far. My question then -

What use are raintite fittings for EMT and the like? They serve no purpose whatsoever other than to increase the cost of the installation.

They are listed and approved (presumably) for wet and damp locations where set screw connectors are not?

 

[Nuber]

They are listed and approved (presumably) for wet and damp locations where set screw connectors are not?

I was intending the comparison between compression and raintite. I agree that SS are not rated for wet location use.

In other words if you use raintite fittings and the inside of the raceway is still wet location, and the same is true for compression fittings, I see no value or use for raintite fittings. They are a waste of money.

 

[electrofelon]

I was intending the comparison between compression and raintite. I agree that SS are not rated for wet location use.

In other words if you use raintite fittings and the inside of the raceway is still wet location.....

Yes, us common people must not be smart enough to follow the code writers' genius logic. Maybe in the next life I will have enough intelligence for this to make sense...

 

[LarryFine]

In other words if you use raintite fittings and the inside of the raceway is still wet location, and the same is true for compression fittings, I see no value or use for raintite fittings. They are a waste of money.

On this, I agree with you.

 

[electrofelon]

Yes, us common people must not be smart enough to follow the code writers' genius logic. Maybe in the next life I will have enough intelligence for this to make sense...

Just a little aside:. Does anyone else besides me have excessive paranoia about misspelling "intelligence"? (Or misspelling "misspelling")

 

[LarryFine]

Just a little aside:. Does anyone else besides me have excessive paranoia about misspelling "intelligence"? (Or misspelling "misspelling")

Noe.

 

[Fred B]

I would be curious as to what is the "specified test conditions" that the definition in Article 100 for "raintight" are?

 

[Fred B]

I would be curious as to what is the "specified test conditions" that the definition in Article 100 for "raintight" are?

Particularly given most have indicated pipes full of water even with use of rain tight fittings.

 

[don_resqcapt19]

Your proposal was only to clarify if the interior was dry or wet. You probably were not involved with the manufacturers pushing a product that is not necessary.

The rain tight fitting issue was really a product standard issue and not a code issue. The product standard was changed and the code followed that change.

 

[James L]

Particularly given most have indicated pipes full of water even with use of rain tight fittings.

Water welling up in a pipe and water falling from the sky must be two different kinds if water

 

[JohnE]

I was intending the comparison between compression and raintite. I agree that SS are not rated for wet location use.

In other words if you use raintite fittings and the inside of the raceway is still wet location, and the same is true for compression fittings, I see no value or use for raintite fittings. They are a waste of money.

Got it, I misunderstood.

 

[MTW]

If the conduit is not airtight, and has a difference of temperature or pressure at each end, air will enter, and that will allow humidity to enter, which will condensate inside the conduit. It will eventually happen, even if every conduit fitting is caulked on the exterior after installation. Sealing the ends help prevent air infiltration and hence condensation buildup. But the interior is never a dry location at all times. Hence the requirement to arrange for drainage.

 

[James L]

If the conduit is not airtight, and has a difference of temperature or pressure at each end, air will enter, and that will allow humidity to enter, which will condensate inside the conduit. It will eventually happen, even if every conduit fitting is caulked on the exterior after installation. Sealing the ends help prevent air infiltration and hence condensation buildup. But the interior is never a dry location at all times. Hence the requirement to arrange for drainage.

I think caulking a conduit airtight is like caulking the bottom edge of a storm window. People who do that don't understand that moisture has to be able to get out