Floats at sewer plant

[jimbo123]

Can floats be hung down 25" to water in a wet well or do they have to be in rmc? These floats are hung by cables up to splice box with rmc sealed going out to control cabinet.

 

[augie47]

Is the area a classified area ?
If so, are the floats on an intrinsically safe circuit (they usually are) ?

The MC is a whole different issue.

 

[hockeyoligist2]

Most wet wells are not considered a classified area, so you should be OK. The standard practice of all of the contractors we use install a weather proof stainless box at the top of the well. Then hang the floats with a strain relief. You local codes may vary.

 

[tom baker]

Most wet wells are not considered a classified area, so you should be OK. The standard practice of all of the contractors we use install a weather proof stainless box at the top of the well. Then hang the floats with a strain relief. You local codes may vary.

There is an NFPA standard on WWTP and Liftstations, commerical wet wells are class 1 div 1. (NFPA 820)
I would not run rigid in a wetwell unless its PVC coated. We typically hang the cords with SS baskets, and run the cord out to j box outside the wetwell. You don't want to be making a connection in the wetwell.

And use IS control for the floats, its much easier and less expensive.

 

[augie47]

There is an NFPA standard on WWTP and Liftstations, commerical wet wells are class 1 div 1. (NFPA 820)
I would not run rigid in a wetwell unless its PVC coated. We typically hang the cords with SS baskets, and run the cord out to j box outside the wetwell. You don't want to be making a connection in the wetwell.

And use IS control for the floats, its much easier and less expensive.

I'm in total agreement.
Great advice, IMHO.

 

[jimbo123]

Thanks for the great help with this situation. Will make some changes.

 

[tom baker]

I've done liftstations with floats, bubblers, pressure transmitters and ultrasonics. Some will work here but not there, Grease, rags, pressure changes all cause issues. I like the ultrasonics. But anything in or around a wetwell takes a lot of maintenance.
And another issue with floats is some have mercury and are hazardous if the mercury gets out, you get your name in the paper and guys in moon suits show up.

I do a lot of fresh water reservoirs, install a pressure transmitter that is accurate to a 0.1" and it works for 30 years. Waste water is a tough environment.