protecting outlets with shared neutral

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electricalist

electricalist

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Location
dallas tx
Customer had a duplex outlet removed. The junction was not pigtailed to device. Because of this the neutral was lifted or opened, feeding opposing phase or phases, burning up equipment.
I thought afci outlets could help but as Kwired explained this may not solve my problem.
Will a gfci sense the curent on the neutral and trip or stop working?.
Any input is greatly appreciated.
This bldg is for detaining individuals and total access to outlets and cost are an issue. Is there a sollution possible.
 
thanks Jumper, I wasn't sure if he was letting me know what was wrong with the install or stating the solution.
They said it burnt up the ups. If this is true and checking any joint on a mwbc is not possible then what would be cheaper than burning up a ups? If you re gonna burn something up.
A GFCI wont work on a shared neutral .....I dont know why i even asked ,,,Im a :dunce:
 
electricalist said:
A GFCI wont work on a shared neutral .....I dont know why i even asked ,,,Im a :dunce:
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A two pole GFCI breaker will work just fine on an MWBC because the shared neutral and both hots originate at that one breaker.
But you are correct that a receptacle type GFCI will not work on a shared neutral to protect downstream outlets unless you convert to an individual neutral where the circuit exits the load terminals of the GFCI receptacle.
But even a two pole GFCI breaker will not protect loads against the effect of an interrupted neutral, since the current through the breaker will still be balanced. :(

Now there is a slight chance that GFCI receptacles in all of the outlets on the circuit, without using the load pass through terminals, will get blown up by the voltage from a lost neutral in time to protect the equipment plugged into those outlets. But it would be a long shot AND the cost of pigtailing the neutral all of the existing receptales will probably be less than the cost of changing every receptacle to GFCI.

What you can count on with the right design is that a full time UPS which always runs the loads off the inverter even while the grid is up should prevent the high voltage on the line side from damaging the loads on that UPS. It would either handle things just fine or sacrifice itself to save the loads.
 
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the cost of pigtailing the neutral all of the existing receptales will probably be less than the cost of changing every receptical to a gfci.
I learn more and more with every experience that offering the right service to the customer is probably the best deal , the easier task overall for me , and most likely the best outcome,,,yet when they start the,,,save me money ,,,find a way,, thats why we call you, and every other reason they give,,,,i wanna be the light at the end of the tunnel.:happyno:

 
Install two/three pole breakers or proper handle ties, then you will shut off all ungrounded conductors when you turn off the supply to work on the circuit.

If you are replacing these receptacles hot, you may want to reconsider your safe working practices for several reasons.
 
Thanks Kwired.
Its a jail and a inmate somehow got the plug out of the wall to hide something. When they realized this they removed the device.. the neutral and hot used the device as a splice point..the person who removed the device. Attempted to wirenut the neutrals, but they werent connecting. Then equipment burnt up so he seperated them and wirenutted each neutral
When I showed up I see black and blue passing through and red at device box with neutral s. neutral to ground had voltage the other did not. Ground to 2nd neutral had continuity. . All the signs of the opened neutral. Shut off breaker re connect in and out hots and neutrals. Every thing is fine.
If this was the original electricians method for splicing the most of the plugs in that bldg need to be checked.
 
jumper said:
I would have thought that jails or such would have tamper proof/resistant screws making it harder to get into device boxes.
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They probably do, but inmates have plenty of time to think about how to do things like this as well. Even my dog in a kennel surprises me sometimes with some of the things he does - either for entertainment or as an attempt to escape.
 
jumper said:
I would have thought that jails or such would have tamper proof/resistant screws making it harder to get into device boxes.
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kwired said:
They probably do, but inmates have plenty of time to think about how to do things like this as well. ...
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One of the methods used is to heat up the end of their toothbrush, push it against the tapper resistant screw, let it cool and use that makshift tool to remove the screw. The #6 and 8 screws used on devices do not take a lot of torque to remove and the makeshift tool works fine for removing them.
 
its a small town. Its not funny but i thought, he pulled the device out and said hmmm,,,,3 hots 1 neutral,,then smiled ,,3 hots no neutral....
 
don_resqcapt19 said:
One of the methods used is to heat up the end of their toothbrush, push it against the tapper resistant screw, let it cool and use that makshift tool to remove the screw. The #6 and 8 screws used on devices do not take a lot of torque to remove and the makeshift tool works fine for removing them.
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which side of the walls is this experience from? :)
 
kwired said:
which side of the walls is this experience from? :)
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no comment:)

Actually the company I worked for did a lot of prison work...Probably over 3 years for me, and one of our foreman had about 7 straight years working in various prisons in Illinois. The boss liked bidding state work...no bid shopping as the electrical contracts were all direct with state, not with a general contractor.
 
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