weathertight bulkhead options with LFMC fitting on one side, EMT (or multi-conductor cable) on the other side?

[emiller233]

what is the best way to pass through a metal wall of a sea freight shipping container (keeping it weathertight) and into a junction box with terminals.
For the exterior side of the wall, it will be a LFMC 90-degree fitting or possibly a LB fitting.
and either EMT with rain-tight fittings or multi-conductor cable with a cord grip on the interior side of the wall.

Everything needs to pass an inspection in the US and possibly Canada.

The customer wants us to drill holes through the wall and weld conduit couplings onto it as needed for each conduit. I'm guessing this would never fly.

cable runs are 480vac 3-phase and 120/240VAC

 

[don_resqcapt19]

Welding is not permitted by the NEC. The issue will be that the listed conduit bulkhead fittings have only been investigated for use with the male threads of IMC or RMC, and you intend to make connections using EMT or cable connectors.

https://www.eaton.com/us/en-us/skuPage.STTBA%204.html

 

[LarryFine]

What about screwing a box with a thread rear hole (or any box w/lock-nut) directly onto the angle connector (or LB w/close nipple) inside the container, with an O-ring on the outside of the container wall?

 

[emiller233]

Welding is not permitted by the NEC. The issue will be that the listed conduit bulkhead fittings have only been investigated for use with the male threads of IMC or RMC, and you intend to make connections using EMT or cable connectors.

https://www.eaton.com/us/en-us/skuPage.STTBA%204.html

Thanks! Thats exactly what i was looking at. But for code compliance, on the inside we'd have to use a close nipple and then a rigid to EMT coupler?

 

[don_resqcapt19]

Thanks! Thats exactly what i was looking at. But for code compliance, on the inside we'd have to use a close nipple and then a rigid to EMT coupler?

Yes, you need connection fittings on both sides as that bulkhead connector has only been evaluated for use with the male threads of IMC and RMC.
It has not been evaluated for use with the threads of any conduit or cable connector.

 

[busman]

I do a bunch or work on Navy and Merchant vessels. What you want is a Multiple Cable Transit Device. They meet ABS requirements for watertight bulkheads. Roxtec is the premier manufacturer. Each of the blocks has multiple peel away layers to match pretty much ANY cable/conduit diameter. The bolts at the top squeeze down on the stack when tightened. You can get them in EMI sealing type also.

Mark

 

[electrofelon]

Welding is not permitted by the NEC.

What exactly do you mean by this? Where does it say that and in what context or application?

 

[infinity]

What exactly do you mean by this? Where does it say that and in what context or application?

300.18(B). I would weld a coupling in place and not the actual raceway.

(B) Welding. Metal raceways shall not be supported, terminated, or connected by welding to the raceway unless specifically
designed to be or otherwise specifically permitted to be in this Code.

 

[electrofelon]

300.18(B). I would weld a coupling in place and not the actual raceway.

Thanks, I never noticed that section. But yeah thats what I was thinking, weld a coupling to the tank. Also, I dont read that section as prohibiting a stick of RGS from passing thru the tank and being welded to it.

 

[emiller233]

I do a bunch or work on Navy and Merchant vessels. What you want is a Multiple Cable Transit Device. They meet ABS requirements for watertight bulkheads. Roxtec is the premier manufacturer. Each of the blocks has multiple peel away layers to match pretty much ANY cable/conduit diameter. The bolts at the top squeeze down on the stack when tightened. You can get them in EMI sealing type also.

Mark

View attachment 2574440

definitely checking into these, thanks!

 

[emiller233]

Thanks, I never noticed that section. But yeah thats what I was thinking, weld a coupling to the tank. Also, I dont read that section as prohibiting a stick of RGS from passing thru the tank and being welded to it.

300.18(B). I would weld a coupling in place and not the actual raceway.

so we could weld a coupling and use the for the bulkhead by the looks of it?

 

[electrofelon]

so we could weld a coupling and use the for the bulkhead by the looks of it?

As long as you have another code compliant support for the raceway, I don't see a Prohibition.

 

[electrofelon]

That said, welding does seem over the top to me. Why not just a chase nipple with lock nuts and some silicone?

 

[emiller233]

That said, welding does seem over the top to me. Why not just a chase nipple with lock nuts and some silicone?

That is exactly what i proposed to them originally, a nipple with a sealing locknut on both sides of the wall. their response was "there's not enough threads left for the next fitting"
there will be some unistrut right after this for support

 

[infinity]

That is exactly what i proposed to them originally, a nipple with a sealing locknut on both sides of the wall. their response was "there's not enough threads left for the next fitting"
there will be some unistrut right after this for support

If you have coupling the length can be extending by using a nipple.

 

[retirede]

That is exactly what i proposed to them originally, a nipple with a sealing locknut on both sides of the wall. their response was "there's not enough threads left for the next fitting"
there will be some unistrut right after this for support

You can make the nipple any length you want. What am I missing?

 

[gadfly56]

That said, welding does seem over the top to me. Why not just a chase nipple with lock nuts and some silicone?

Another potential option is a Swagelok bulkhead fitting. You can get one for any size of EMT, which is just tubing as far as Swagelok is concerned. You can get them to terminate the EMT on one or both sides with NPT threads on either. They can also do a pass-through for the EMT if you want to go that way.

High-Quality Fluid System Solutions & Components

Swagelok is a privately held manufacturer of fluid system solutions including components, assemblies, and services trusted in critical industries worldwide

www.swagelok.com

 

[norcal]

What about a Myers Hub type bulkhead fitting?

 

[emiller233]

You can make the nipple any length you want. What am I missing?

That was just their response, they're fighting the nipple idea for whatever reason...?. I've told them its the cheapest option and they said they needed a different option without raising the cost much. They're mostly 2" runs, so they're just trying to avoid the cost of proper bulkhead fittings is about what it comes down to

 

[emiller233]

What about a Myers Hub type bulkhead fitting?

thats probably what will end up being used, and they're just gonna have to open up their wallet a little bit more to do so. they're telling us there are cheaper ways to do it than using these, but they don't like any of those options, so...