As a field service technician, I see many water damaged control panels. Numerous instances of water leaking into underground vaults where electrical control panels are tucked away.
There are two types of underground vaults: Ones that leak and ones that eventually will leak. I’ll tell you how to prepare for this eventuality and one way to trouble shoot a water damaged control panel.
Just recently, it happened again, this time in an area of Dallas that is well-known as a low-lying area and prone to flash flooding. The application was a pump for a large, public water display – complete with coordinated lights, laser show, music, etc. Fun stuff....when the pump works. Not so fun when it doesn’t. The customer called our 24-hour field service line and the game was on.
The pump, motor, and controls all were all located in an underground concrete vault beneath the display. Time to troubleshoot. If you run into this problem, here are the steps I would suggest taking to troubleshoot a water damaged control panel:
- First, check the motor contactor to see if you can manually close it and make the pump run. If so, the pump is OK.
- Now that we know the pump is OK, I backtracked the control signal for the contactor to the main control cabinet. The relay which should have been pulling the coil of the motor contactor in was energized, but the relay contacts going to the pump contactor had no voltage.
- I removed the relay to find that the pins for the contacts in question had corroded off because of water intrusion into the cabinet (from leaks in the ceiling of the vault).
I delivered a spare relay to the customer the next day as well as several spare relays just in case. Obviously, this could have been much worse and complications in the troubleshooting I described could be beyond the scope of this article. However, prevention is better than anything. There are several ways they can keep control panel water damage from happening again.
- Keep water out of the cabinet, period. Make sure all seals around doors are in good shape.
- Ensure that all connectors penetrating the enclosure and tight and water proofed.
- Make sure the crew keeps the door to the enclosure closed.
- If the vault leaks cannot be repaired at street level, a shield or “umbrella” of some type should be constructed to fit over the electrical cabinet. This would force any water leaking from street level away from the cabinet and hopefully minimize if not eliminate future water damage.
This was a relatively easy and inexpensive repair – a simple relay had failed. But had
other electronic components (AC Drives, PLCs, power supplies) in the control panel enclosure sustained water damage, the cost would have been substantial and the water show have been down for a significant period of time.
Lonnie Gillilan is IIDM's Dallas field service manager and an avid stock car follower. You can reach him at firstname.lastname@example.org.