Electrician Talk banner

Lift Station Seals

12K views 28 replies 10 participants last post by  Ty the electric guy 
#1 ·
How do you guys typically seal cables going from the lift pumps to the starters?

Almost all lift pumps come with a preinstalled SOW cord on it. Problem is that most lift stations are Class 1 Div 1 and last thing you want to do is put the cord through an EYS seal as you'll never be able to remove the pump from service without cutting the cord.

Alternatively you could stub up conduit 6" from the wet well and run the SOW to a JB that is 3ft away to avoid the classification. I guess now you would have to mechanically protect the SAW though.

What do you guys do?
 
#5 ·
This is rife with code violations but it works.......

I stub a 2" PVC into the side of the wetwell, then a PVC 90º then a rigid nipple into the starter can. I thread the rigid enough so about 1" of threads are exposed inside the can after the locknuts are on.

Then I screw a 2" X 1" or 1 - 1/4" plumbing bell reducer on the pipe inside the can. Use pipe dope, this needs to seal. Newt, I screw a cordgrip into the reducer and terminate the words on the starter.

The net result is when the pump needs to be pulled, simply loosen the cordgrip, pull the SO cord back to the wetwell, and pull the new pump cord back into the starter.
 
#12 ·
My thoughts are that the pump as a complete unit including the cable is an explosion proof device - therefore we have to follow standard classified location wiring methods. Sure, SOW is not rated on it's own, but it has a classified rating as part of the pump package. I would think an inspector would twitch a bit if he saw terminations in the classified location.
 
#7 ·
I recently did a lift station this way. The SOW connectors were a PITA to get and we had to file out the inside as the ones where the gland sealed properly, were too small in the metal throat.
 

Attachments

#9 ·
The trick to these is to get the classified area agreed upon.

If 18" is the height of the classified location (maybe have to get a couple three feet away from the manhole) then you install a pvc conduit from the well to under your control cabinet. Don't let the PVC terminate above the 18", keep it below so it stays in the classified location.

Then bring the cables through the conduit and up into the cabinet in free air (use an appropriate cord connector).

The idea is that the cords have no splices and therefore they do not need to be sealed. The conduit does not leave the classified location so it does not need x-proof sealing (I would duct seal it).

They send those long cords for a reason. If you start running them all in a 2" conduit and seal it x-proof then changing out components in the future is an experience. I came behind someone who put a j-box in the tank and cut the cables short and spliced them. What a mess.
 
#10 ·
What article is driving the classification of this?
 
#13 ·
Is the starter in a classified area? If you use your JB option, are you sealing there? Is it a vented JB?

Why not splice in the zone 1 area? It's done all the time in other applications...

Similar install - Pretty much every pumpjack I've done has a pressure switch on the stuffing box that is wired with SOW. Sealed at the switch and a weatherproof receptacle on the other end in an unclassified area with no seal... No issue..
 
#16 ·
Why not splice in the zone 1 area?
Why do it if you can engineer around doing it? It's a point of failure.
It's done all the time in other applications...
I bet because it could not be easily engineered around doing it.
Similar install - Pretty much every pumpjack I've done has a pressure switch on the stuffing box that is wired with SOW. Sealed at the switch and a weatherproof receptacle on the other end in an unclassified area with no seal... No issue..
I think you made my point?
 
#15 ·
The pumps and float switches are fed with cord and that cord is sealed at the pump or switch end. That cord is OK to be down in the pit (in the most dangerous part of the installation. So if that cord is installed w/out any splices to an area outside of the classified location, why does it need to be sealed with x-proof seals?

What code section is being used to justify the opinion it needs to be x-proof sealed?
 
#17 ·
The pumps and float switches are fed with cord and that cord is sealed at the pump or switch end. That cord is OK to be down in the pit (in the most dangerous part of the installation. So if that cord is installed w/out any splices to an area outside of the classified location, why does it need to be sealed with x-proof seals?

What code section is being used to justify the opinion it needs to be x-proof sealed?
The rules may be different between the USA and Canada... don't know.

We are required to separate the zones so the fact that the SOW is / is not rated really is not an issue if it stays inside the zone. I don't believe separation by distance is an option in our code.

I don't think I have ever run into the situation, but lets say I had some device inside the zone connected to some sort of pendent controller and I ran the controller well outside the zone (say could not physically bring inside the zone), I would still have to seal the cable at the pendant.

No different here, I need to seal between the zones (rule 18-154). By putting the junction inside the zone and sealing ahead of the JB allows me to use standard wiring methods and materials inside the zone.

Cheers
John
 
#24 ·
the cable is part of an approved assembly. As long as the cable has a continuous sheath and is sealed where it enters the motor, you shouldn't need a seal at the Jb outside the hazardous area. We did one this past October and the inspector passed it. The attached picture is upside down because it wants to be. Bottom of JB is 26" off the deck, and the cables have kellum grips just under the cover for strain relief.
 
#25 · (Edited)
the cable is part of an approved assembly. As long as the cable has a continuous sheath and is sealed where it enters the motor, you shouldn't need a seal at the Jb outside the hazardous area. We did one this past October and the inspector passed it. The attached picture is upside down because it wants to be. Bottom of JB is 26" off the deck, and the cables have kellum grips just under the cover for strain relief.
View attachment 105410
The difference with what I'm use to is an enclosure with screens around the bottom, top, whatever.

We had one blowup with a guy standing on it checking flow meters. So some have moved off the top. He lived, but was thrown 20 yards. Top stayed intact, just landed upside down. I'll look for pictures tonight.
 
#26 ·
So that makes sense to me if the cable is not SOW, because I suspect the cable is rated to not pass vapours / gases. The gland at the box is likely suitable for the purpose and still is not a standard gland but a "cable seal" gland.

The pipe is not a complete system, so there is so sealing required and the short pieces on top are for mechanical protection. If the box is 26" away, I assume that it is outside the zone, so it is all good.

So if the cable is not rated or the box is still inside the zone or the conduit system is complete we are back at scratch.

Cheers
John

P.S. just wanted to add that it is nice looking installation!
 
#29 ·
The way this is usually done in my area is by putting seals directly below the control panel. Below the seals is a large NEMA 4x junction box(class 1, zone 2) with a bunch of terminal blocks. Than pipe from the junction box into the lift stations.

The SOW comes from the pump/floats and terminates in the junction box without any seal. Thhn/rw90 runs from the junction box to the control panel with a seal in between. Kellems grip inside the junction box to support the SOW.


Sent from my iPhone using Tapatalk
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top