Arc Fault issues

[jasonapost]

Hello,

I am an electrician who is having an issue with arc faults in a Hotel almost out of warranty. 5 stories stacked units on one main feeder (fed through), when we turn the dishwasher (dedicated non arc fault) on in the second floor unit one of the arc faults in the same unit trips. The same on the first, third, fourth, and fifth and only in those shared feeder rooms. We have changed arc fault breakers, tightend lugs, isolated test neutrals, and we can not seem to find the problem. Any advice?

 

[LISHAJI]

How about the test button to see if it trips!!

 

[Sierrasparky]

one of the test proceedure is to replace the breakers that trips with a GFCI breaker if it still trips then there could be a ground leakage.
since the problem is in multiple units and the dishwasher is creating the sympton I would look for something relating to the water pipe. Maybe there is a grounding issue or no bonding.

 

[Dennis Alwon]

I have heard of these issues before but I am not sure of the solution. I would contact the afci manufacturer and see if they have a different generation afci and see if the same issue arises.

I had a situation like that with a fan- we used GE afci- I called and they sent me 5 free afci that were of an older generation but still the combo units. That solved the issue.

Being that all the breakers are the same age and all the dw probably the same brand I suspect something weird electronically going on.

 

[jasonapost]

An electronic problem may sense but this is a 5 story 250 room hotel. We are only having the problem in 5 rooms. Cutler Hammer Arc Faults are being used and not sure the dishwasher brand. If the problem is electronic would't that cause a problem in all rooms. My company did the wiring from the ground up. We purchased and floated material cost from the start so all Arc Faults must me the same gen. I will call the technical number though to see if they may have a soulution.

 

[jasonapost]

Figured it out. While constructing the building, we needed to hire "skilled Labor" from a trade temp, I will not mention the name to keep me out of the liable world. It became clear, when we tried to move the neutral feeders to tighten the grounds, that all the neutrals in the panel were not tight. I mean...LOOOSEEEE. One fell out of the lugs as we moved it. Rest assured the foreman, and the temp company, will not hear the end of this.

 

[Sierrasparky]

OK great, So why would a loose nuetral trip a AFCI? Would this be a sieries arc? and thus not sensed by the AFCI as stated in another tread?

 

[jasonapost]

Not sure how. My theory is: could be the arc was only sensed when the dishwasher applied load to the shared phase. Arc fault and dishwasher circuit shared phase A. The other Arc Fault for the 2nd sleeping area was on phase B and did not trip. I am only an electrician (yes I have my masters, but I test well) who installs and troubleshoots until it works, mabye an electrical engineer who can do more than draw straight lines on a plan could answer better. :angel: