A Question About Piping. Flex PVC vs Liquid-Tight Conduit

[Solar guy]

I've looked at dozens of videos on pond construction and am always looking for cross trade solutions. One thing I have noticed is the black or gray flexible PVC pipe that usually runs from the pump in the skimmer to the bog or bio-falls looks an awful lot like flexible conduit we electricians call liquid-tight. Could this be used for this purpose? Anybody ever tried this?

 

[combatwombat]

I had the same thought when i first started estimating materials for my build. Unfortunately, I don't know the answer as far as pressure rating (probably isn't rated at all but might work anyway) or compatibility with fittings because I found that 2" liquid tight is hard to find (gotta go to the big boy electrical house to find it around here) and it is SIGNIFICANTLY more expensive. Almost double the price. And flex PVC is already significantly more expensive than the normal stuff.

What I do know is that long sweep PVC conduit elbows are often used on pond builds as they mate with any other schedule 40 pvc and pressure rated long sweeps are hard to find and expensive.

 

[mgmine]

If it holds water and can be connected together it will work. Pressure isn't really a problem unless you were to shut one end off while keeping the pump going. Since there isn't a reason to do that the pipe won't burst.

 

[combatwombat]

If it holds water and can be connected together it will work. Pressure isn't really a problem unless you were to shut one end off while keeping the pump going. Since there isn't a reason to do that the pipe won't burst.

It is potentially a problem if you run any of your plumbing outside of the pond.

 

[mgmine]

It is potentially a problem if you run any of your plumbing outside of the pond.

How? I once used a discharge hose as a water line which is certainly not a hose to be used under any circumstance and it worked.

 

[combatwombat]

How? I once used a discharge hose as a water line which is certainly not a hose to be used under any circumstance and it worked.

When I was two, my mom says I ate a piece of cat poop but didn’t get sick. Doesn’t mean it’s a good idea to eat cat poop for breakfast.

 

[poconojoe]

If you truly are an Electrician, I'm surprised you would you even consider that.

Dont use sealtite (liquidtite).
It's not made to hold water, it's made to hold water out.
But, the big reason is the inside is metal, not coated with plastic.

Just buy schedule 40 flex PVC.
If it's the color you are concerned about, they also make it in black, not just white.
It's not really that expensive. I bought a 25 foot roll of black 1-1/2" for $50 on Amazon.
Considering it will last many years and will outlast anything out there, it's well worth it.

And consider this... schedule 40 flex PVC is fully compatible with all schedule 40 ridgid fittings, including primer and glue. You can mix and match anything that's schedule 40.

 

[combatwombat]

But, the big reason is the inside is metal, not coated with plastic.

I think you're referring to LFMC. There is also LFNC (non-metallic). That's far more commonly used around here than LFMC. Still agree with you that using flexible electrical conduit doesn't make any sense.

Flex PVC is perfectly affordable when you're looking at 2" or less. But start pricing out 3" or larger and it gets ridiculous very fast. Same applies to rigid PVC as well, but it's much less expensive than flex.

@mgmine: I noticed that you mentioned that the pipe would not burst. I think you're right about that, but that would not be my concern. I would be much more concerned about fittings leaking. And there are lots of times when you might shut off flow to some area of your pond system without shutting down your pump.

 

[mgmine]

When I was two, my mom says I ate a piece of cat poop but didn’t get sick. Doesn’t mean it’s a good idea to eat cat poop for breakfast.

I'm not saying it's a good idea I'm saying If it holds water and can be connected together it will work. If the fittings leak then it can't be connected together. If it leaks then it won't work. Maybe the solar guy has a mile of pipe in the back of his truck. If I had it laying around I might use it. I used grey PVC electrical bulkheads for my filter connection. I did so because the threads were longer.