Floor Box With Water Breaker Does Not Trip

[ed downey]

I Got A Call From One Of Our Project Managers That Indicated He Had A Floor Box In A School That Got Water In It. The Water Did Not Completely Cover The Duplex Receptacle But It Did Come Up To The Midway Point On A Horizontally Mounted Duplex (Therefore I Think It Covered The Neutral But Not The Hot Side Of The Device).

The School Says That They Saw The Water Steaming Up And The Circuit Breaker Never Tripped.

I Have Two Questions:
1.) Could The Duplex Have Gotten Wet Partially Onto The Hot Side With A Large Resistance And Not Tripped The Circuit Breaker. Can You Think Of Any Other Reason Why This Situation Did Not Trip The Breaker?
2.) The Water Is Now All Cleaned Up. How Can I Test The Device? Should I Have The Electrical Contractor Replace The Devices Affected.
Thanks,
Ed

 

[Ed MacLaren]

Re: Floor Box With Water Breaker Does Not Trip

Question 1
Yes, pure water is an insulator, dirty water has resistance, and the amount of resistance depends on the impurity.

Circuit breakers are an assembly of components that can fail. That is why I have a fuse panel in my house. The breaker could be tested by your electrical contractor.


Question 2
Replace the receptacle.
Ed

 

[a.wayne3@verizon.net]

Re: Floor Box With Water Breaker Does Not Trip

Ed your theory is sound...dirty water like salt water conducts electricity.But I have always wondered why floor box receptacles are not required to be gfci protected ??? How much more of a wet location can you be but in the ground???
if they were gfci receptacles then the circuit would have tripped.Or am I wrong ????????

 

[Guest]

Re: Floor Box With Water Breaker Does Not Trip

Ed,
I like your fuse box idea. Do you install a circuit breaker box too, or just a fuse box? Fuse failure is very rare.

I have seen many floor receptacles that were not covered when the plug was removed. Over time they filled with dirt to the point they would take or hold a plug. Talk about dirty water if they got wet!

It seems that floor plugs are prone to misuse and prone to unsafe incidents. It would make more sense for the box to be much bigger; the receptacle mounted sideways; a drain provided if installed near grade level; and a GFCI/AFCI to lock it all down. Floor receptacles should have a protective cover that is closable when the device is plugged in-- and a "raceway" to bring the cord end over to the protection of the closest wall. That would be a real production! Floor plugs are a blessing & a menace!

[ September 16, 2003, 08:39 PM: Message edited by: awwt ]

 

[Ed MacLaren]

Re: Floor Box With Water Breaker Does Not Trip

I like your fuse box idea.- - - - Fuse failure is very rare.

Right, fuses, if they fail, fail in a safe (open) mode. There are some misguided folks (my insurance company) that have come to believe that fuses are inferior to circuit breakers.

Of course, we know that the fault lies with the ignorant home occupant, who has a tendancy to overfuse.

The breaker's main feature, convenience is great in industrial applications where overloads can routinely occur.

In a correctly designed and wired residence, there shouldn't be any overloads. I can't remember ever blowing a fuse in my home.

Ed

[ September 16, 2003, 09:32 PM: Message edited by: Ed MacLaren ]

 

[flightline]

Re: Floor Box With Water Breaker Does Not Trip

This is a little off subject, but we have had more than one occasion where a splice or nick in a conductor in an underground raceway or handhole/manhole has caused the whole ting to become a boiling cauldron where the lid and frame became too hot to touch, where steam was literally belching from the openings in the cover, and still no opened fuse or breaker. Albeit most of the lighting circuits were much higher amperage, for what we later pulled out of there, you would be surprised.

 

[hurk27]

Re: Floor Box With Water Breaker Does Not Trip

This is how metal gets platted. and it gets very hot too.

 

[gwz2]

Re: Floor Box With Water Breaker Does Not Trip

Back to the original post and question.

Ohms Law.

I = E / R

If the resistance of the boiling water is not low enough to cause a substained current flow greater than the OCPD rating, then the water will boil until evaporated and then usually much HIGHER resistance.

Example: R = E / I , were E = 120 volts and I = 15A OCPD.

E / I

120V / 15amps = 8 Ohms.

Does the water provide a substained resistance of 8 ohms ?

Circuit Breakers usually have a 6 to 8 times current delay to start motors. 6 * 15 amps = 90 amps.

120V / 90 amps = 1.333 Ohms.

Does the water present a resistance of less than 1.33 ohms for a quick opening of the OCPD ?

[ September 17, 2003, 07:42 AM: Message edited by: gwz2 ]

 

[ed downey]

Re: Floor Box With Water Breaker Does Not Trip

Thanks, For All The Responses. I Believe The Water Was Very Dirty Since It Rained Steadly And Then Migrated Into The Floor Box That Was Not Completely Cleaned Up. So The Water Causing A High Resistance Is Probably My Best Bet At THis Point. I Will Go Out To The Site And Let You Know If I Come Across Anything Else.
-Ed

 

[brian john]

Re: Floor Box With Water Breaker Does Not Trip

Ed:

My mains are fused safety switches all my outlet circuits are GFCI's the lighting circuits are standard Square D QO CB's.

I test CB's and there is a certain percentage of failures. Seldom test fuses (but have). The fuses fall into a tight curve and did open. Molded case CB's have a much wider curve.

JUST A STATEMENT , not for lawyer dissemination.