Dual function breaker on a sump pump?

[KyleFowler]

Today I went to a bank that had an off the shelf 120v sump pump that caught fire. Not really sure why it caught fire the pit was only damp, no standing water inside it. The pump however was very old looking and probably original to the building (mid 80s) because it is very difficult to access. It's underneath the drive through lanes underground in a 48 inch corrugated metal culvert pipe because the vacuum tube lines run in the culvert pipe as well.

My question is would it be a bad idea to put the replacement sump pump on a dual function afci/gfci breaker? Or would it nuisance trip? Apparently a dual function QOB is $350 so I'd hate to install it and then have to turn around and remove it lol. I'd like to put it on a breaker versus a device because of the humidity down there.

 

[FionaZuppa]

Why dual breaker? General GFCI will suffice.

The float activates a switch on top of the old pump? Under that top cover I bet ya there are wires that are crimped onto pins, and those crimps got corroded and maybe caught fire?

Nuisance tripping is hit-miss. My own Wayne 120v sump pump (for outside pit) is on gfci breaker, the pump runs on/off when it rains, never had an issue with nuisance tripping.

Pumps that have integrated VFD may be a nuisance issue.

 

[mopowr steve]

Although the pump should be GFCI protected, what’s really at stake here anyway if a pump catches fire in this pit anyhow? Is there anything within or near the pit that is combustible and could spread?

 

[texie]

I would never install AFCI on a branch circuit that it is not required by the NEC. Never, ever. We struggle enough with them where they are required. Pure snake oil.

 

[KyleFowler]

Thanks for the replies everyone, I was thinking about using a dual function because apparently that pit never really gets any water in it and was full of 40 years worth of trash, some of it flammable. How did it get full trash you ask? Well everytime Diebold (or whatever company maintains the pneumatic tubes) work on those tubes they just left their trash. Also above the sump pump pit is a 12x24 inch hole through the floor where teller trash has fallen in.

I'll probably just stick with a GFCI breaker since I have the NEC behind me on that.

 

[Fred B]

AFA the pump catching fire, likely the AFCI nor the GFCI would make much of a difference for a motor that likely has been running "dry" and overheated. The standard breaker should have caught that. Unless the heating first made a short to ground or an arcing fault then maybe either device may have picked it up before flaming. The most likely source was not the motor first but the mechanical parts running dry.

 

[Little Bill]

Thanks for the replies everyone, I was thinking about using a dual function because apparently that pit never really gets any water in it and was full of 40 years worth of trash, some of it flammable. How did it get full trash you ask? Well everytime Diebold (or whatever company maintains the pneumatic tubes) work on those tubes they just left their trash. Also above the sump pump pit is a 12x24 inch hole through the floor where teller trash has fallen in.

I'll probably just stick with a GFCI breaker since I have the NEC behind me on that.

Just what makes you think a DF would help? AFCI off any kind would be a waste of time and money!
Add to that, AFCI not required in a non dwelling.

 

[Fred B]

Just what makes you think a DF would help? AFCI off any kind would be a waste of time and money!
Add to that, AFCI not required in a non dwelling.

Man you won't like the proposed 2023 code. Adding them to bath and garage also.