All wet

[mshields]

We have a client who resides in an area that just experienced their 100 year flood level. This resulted in the facility having an experience of their own; 5 feet of water in one particular mech/elec room, and water raining down from above in other area's.

One very interesting thing, is the fact that despite having 5 feet of water, and despite two dry types being completely submerged, the upstream breakers never tripped. Furthermore, rather than manually de-energizing them, the client left them running! This would certainly not have been my recommendation but this was 8 days ago and everything remains up and running.

With regard to how to advise them, I'm aware of the NETA standard for testing of water damaged equipment but I'm wondering what if anything needs to be done with equipment that was not submerged but might have gotten some connections wet for example.

My expectation is that any such moisture would have long since dryed out and from a practical stand point it should be ok. Comments?

Much appreciated.

Mike

 

[Dennis Alwon]

Generally speaking breakers will work when submerged but even though they are working after they have been dried out they need to be replaced. Their will definitely be issues with those units. The panel board may be able to stay but not the breakers.

 

[brian john]

Mike:

Few weeks back I posted about busway that was soaked and operated, so it does happen meggered at <1megaohm.

All equipment should be cleaned and meggered, the CB's should be visibally inspected and meggered, ductored and high current tested.

In particular look at the fish paper and insulators for contamination or damage.

 

[zog]

We have a client who resides in an area that just experienced their 100 year flood level. This resulted in the facility having an experience of their own; 5 feet of water in one particular mech/elec room, and water raining down from above in other area's.

One very interesting thing, is the fact that despite having 5 feet of water, and despite two dry types being completely submerged, the upstream breakers never tripped. Furthermore, rather than manually de-energizing them, the client left them running! This would certainly not have been my recommendation but this was 8 days ago and everything remains up and running.

With regard to how to advise them, I'm aware of the NETA standard for testing of water damaged equipment but I'm wondering what if anything needs to be done with equipment that was not submerged but might have gotten some connections wet for example.

My expectation is that any such moisture would have long since dryed out and from a practical stand point it should be ok. Comments?

Much appreciated.

Mike

It is not the water you are worried about now, it is all the junk that came in with the water that has contaminated the insulators. Also any breakers woth electronic trip units may not trip anymore and should be tested before they are needed to interupt a fault. Lots of meggering and testing to be done. If they have any MV equipment PD surveys are the most practical thing to do, taht way you can find any problems without a shutdown.

 

[Dennis Alwon]

Mike:

Few weeks back I posted about busway that was soaked and operated, so it does happen meggered at <1megaohm.

All equipment should be cleaned and meggered, the CB's should be visibally inspected and meggered, ductored and high current tested.

In particular look at the fish paper and insulators for contamination or damage.

Brian what is your experience on this. Do you usually have to replace the breakers or do the meg out fine?

 

[brian john]

Bus and insulators are USUALLY fine, if cleaned and tested. My experience with CBs is; RUST sooner or later and that has to be detrimental to their operation. We always recommended replacement of CB's, busways ETC.

As Zog noted we have dried busway, only to have lousy readings, disassembled the busway at the bottom 90 only to find an accumulation of dirt and metal filings.


I actually was able to dry out a submerged transformer 500 KVA, it was in a vault with NO ACCESS, took weeks to get the readings to match a new same size same manufacture transformer.

 

[K8MHZ]

I think operating OCPD's underwater for any period of time may invalidate the warranty........

Or any liability on the mfg's part should one not clear a fault and cause damage, injury or death.

I at least would suggest contacting the manufacturer for clarification.

 

[weressl]

It is not the water you are worried about now, it is all the junk that came in with the water that has contaminated the insulators. Also any breakers woth electronic trip units may not trip anymore and should be tested before they are needed to interupt a fault. Lots of meggering and testing to be done. If they have any MV equipment PD surveys are the most practical thing to do, taht way you can find any problems without a shutdown.

Key point, well said!

The equipment may work now but on the long run it will develop weak spots and fail earlier than expected. Take the time NOW to properly go through the system and clean or replace as necessary.

 

[JohnJ0906]

Here is the NEMA document on water damaged equipment, FWIW.