Water in Pits that trips control circuits

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DesignDesign

New member
I have a situation where a control circuit constantly trips thereby setting off alarms. There is a control sensor inside a water pit located in an open environment. This low voltage circuit sensor located in the pit is fed via buried conduits and an electrical box inside the pit. After several false trips, it was realized that water was entering the electrical box through the conduits. Given that it's a low voltage system, are there other solutions than unearthing the conduits and box? What are the hazards for low voltage systems in a wet environment? Telephone lines are constantly exposed. Would a weep hole be sufficient?
I have not found anything in NEC.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
If a box is filling up with water you need to find a way to prevent the water from getting in, and/or find a way to get it out.

A few small holes drilled in the bottom of the box may well be the simplest answer.
 

tom baker

First Chief Moderator
Staff member
If the sensor can be submerged, then its a matter of sealing the wire connections in the box. King Dry-Conn wire nuts work well.
If the wiring connectionsa are on the sensor, and water is getting into the sensor, then that may not be the best sensor. You can never ever keep water out of underground conduit.
By the way, the NEC has many rules for this application
Try Art 100, 110, and 725.
What are you trying to measure with your sensor?
 

hurk27

Senior Member
I agree with Tom as to not being able to keep water out of underground conduits/ box's, and there several methods to sealing these connections, as the King dri loc's are ok and low cost, but in completely submerged water lodged box's, I use a embedding compound made by GE, we use this method on water fountains where connections must be made underwater in submerged boxes, and can be removed when needed (although a pain) I also like the Ideal Twisters DB. they seem to have more dielectric grease in them.
 

tom baker

First Chief Moderator
Staff member
As above post states, you can pot the boxes with a re-enterable silicon, 3M makes, and its poured in, A silicon like compound that can be dug out.
If the device is nippled to the box, and water can run down into the nipple, then the potting compound is best. I have mag flow meters that after potting can be direct buried with no vault.
What I have learned is to pipe into the vault, LB up to a j box. Drill a small hole in the bottom of the LB, and use duct seal at the j-box. Let the water drain out at the LB.
Also use a better quality wiring method, such as XHHW-2 or tray cable
 
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