Water in conduit?!

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ErichKeane

Making scrap at ludicrous speed.
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About 6 months ago, I was installing a plug for my wife's EV charger that sits outdoors. The charger itself is outdoor rated, and is NEMA14-50.

SO, I bought this enclosure: https://www.amazon.com/gp/product/B08549S8KK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I mounted it about 8 feet in the air off the side of my shop, and wired out the bottom with the big plastic conduit material. It comes straight down about 2 feet, and uses a 90 degree conduit elbow to go through the metal wall of my shop, and directly into a junction box, where I used the Polaris connectors tied everything together (6 gauge wire, so wire nuts were out). I used a TON of silicon sealant on both the inside and outside of the conduit where it entered the building.

Today was our first big rain of the season, and when we went to plug the car in, the light didn't come on! I went into the shop and saw the breaker trip, so flipped it back, just for it to instantly break and release magic smoke from my junction box.

I pulled it apart, and it was pretty fried up, the rubber/plastic on the Polaris connectors (like this: https://www.homedepot.com/p/Polaris...-0B/303578434?source=shoppingads&locale=en-US) were straight charcoal!

It was 'damp' inside the box, so my only theory is that sufficient water got into the box to short something enough to cause catastrophic failure. I'd like to fix it/redo the work in a way that can survive a storm next time!

I pulled the box apart to check for where water could have gotten in. The metal wall of the shop is bone dry, and the silicon sealant around the conduit is perfectly in tact and water tight.

My only guesses are either:
1-condensation: The shop is insulated, but not THAT well? I sometimes get some condensation on machines, but I can't imagine it would have been THAT much to short a significant distance for those connectors.
2- Water got into the conduit through the top, and just poured in. It is still raining NOW, but I didn't see any obvious water coming in now, though I don't know what could have happened otherwise.

So my questions are: Did I do something stupid with the install? Should I have put some sort of sealant inside the conduit to prevent water from getting in/out? How do I prevent this from happening again?
 
So right as I clicked 'submit', it started POURING again, so I ran out to check, and I don't see any water coming out the conduit. Not sure what could have done this.
 
Not seeing exactly your setup it's hard to say, but you may need a drip loop to keep water out of the box.

Could be something else entirely though like insects building a nest inside of it too. Need pictures....

John
 
Did you use aluminum or copper wire . If aluminum wire make sure and use anti corrosion paste on the connections. If not the oxide coating that forms will make resistance at the connection and generate heat.
 
Does the box have any kind of NEMA rating? I would think for the situation you're describing you'd need a MENA 3 or better rating.

The box in the link doesn't look that weather tight to me. Lots of seams and openings to let water in.

Here's a link to some of the NEMA ratings. We used NEMA 6 boxes in areas that had daily washdowns, and even then over time there were occasions when a seal failed.

NEMA Rating Guide for Electronic Enclosures | Bud Industries

NEMA ratings establish a clear guide to waterproof, dust-proof, etc. Click here to see what level of protection is right for you.
www.budind.com www.budind.com
 
This particular problem might be just cause to call in a professional, insured electrician. My .02
 
ErichKeane said:
I used a TON of silicon sealant on both the inside and outside of the conduit where it entered the building.
Click to expand...

This type of conduit has its own glue. Running this is just like running a water line - you glue every joint. Once completed, the system should be water tight.
 
It was definitely copper wire, AND there was anti-corrision paste inside the big lug connectors.

As far as the box, it claimed to be ok outdoors? Perhaps not...
 
Pictures of the install would be a real help here.

Did you also look inside of the outlet box for water?

Are you SURE that all of the plastic conduit joints are sealed and not just stuck together?

Your enclosure claims to be NEMA 3R rated. You need at least a NEMA 4. NEMA 3 does not have any gaskets, it just has all the open edges pointing down hoping that gravity will keep the water out. NEMA 3 or 3R claims to resist wind driven rain, but a really bad storm can have the same force as water from a hose. Nema 4 is rated to resist the force of a hose. WHile NEMA 6 is better yet, it gives protection against submersion. I think if your box gets submerrged the water in the box will be the least of your worries. On all of the outdoor equipment I design uses NEMA 4, and we have not had any complaints from customers. Even in really harsh places.
 
Flyinfool said:
Pictures of the install would be a real help here.

Did you also look inside of the outlet box for water?

Are you SURE that all of the plastic conduit joints are sealed and not just stuck together?

Your enclosure claims to be NEMA 3R rated. You need at least a NEMA 4. NEMA 3 does not have any gaskets, it just has all the open edges pointing down hoping that gravity will keep the water out. NEMA 3 or 3R claims to resist wind driven rain, but a really bad storm can have the same force as water from a hose. Nema 4 is rated to resist the force of a hose. WHile NEMA 6 is better yet, it gives protection against submersion. I think if your box gets submerrged the water in the box will be the least of your worries. On all of the outdoor equipment I design uses NEMA 4, and we have not had any complaints from customers. Even in really harsh places.
Click to expand...
I didn't pull the box down, or get pictures yet. It was 9 at night in a bunch of rain, so all I did was pull the box apart inside the building that had caught fire (looking for the water ingress). Once the sun comes out today I'll snap a few pictures of what I have going on.

The plastic conduit joints all had their own seals in them as far as I remember, and I cranked on them pretty tight. Where it came into the building (around the outside), I used a bunch of silicon caulk to try to keep water out.

I guess I need to stop believing the text online then! All of them say 'weather proof' or 'waterproof', so perhaps that was a lie :)

I've got it under a slight eve, so I thought that would be a bit better for it, but it did rain A LOT yesterday.
 
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