I recently was called to check a cut wire, while installing new decking a roofer nicked a 12/2wg romex, causing the hotwire to come in contact with the ground wire. At the same time this happened the homeowner was washing dishes,he received a pretty good jolt, testing by the homeowner (a plumber by trade) with a multimeter from the nuetral side of a nearby receptacle to the rim of the metal sink, revealed 80volts.The circuit was protected by a 1 pole 20amp Federal Pacific Breaker, which did not trip. After I arrived the 80volts were no longer present, I looked at the romex and the ground wire had burned thru, but the breaker was still on.In this case if the homeowner had been seriously hurt or worse who would be liable.
FPE breaker
- Thread starter jro
- Start date
- Status
- Location
- Illinois
- Occupation
- retired electrician
Re: FPE breaker
jro,
That doesn't sound like any type of breaker problem. It sounds like the EG in the damaged NM is bonded to the water system and not to the grounded conductor and the water system is not properly bonded to the grounded conductor. If the bonding is properly installed there should be almost no voltage between the receptacle neutral and the water pipe.
Don
jro,
That doesn't sound like any type of breaker problem. It sounds like the EG in the damaged NM is bonded to the water system and not to the grounded conductor and the water system is not properly bonded to the grounded conductor. If the bonding is properly installed there should be almost no voltage between the receptacle neutral and the water pipe.
Don
Re: FPE breaker
FPE Breakers have a nasty history; There are contractors who will cut a piece of NMB so they can keep doing the demo and go back to fix it later only to have the cutters completly trashed; FPE (was)is very popular out here; Was the breaker an old wide one where the amp number is the same color as the handle? (probably an old [pre1984]breaker) I was talking to someone who did some research into FPE and it was discovered that the old style did not have a thermal strip in order to open the circuit, so it is not impossible to draw 45amps on a 15 amp breaker and it still will not trip; As far as the shock that was recived it sounds to me that the grounding system is in place and the breaker was feeding the voltage through the gnd wire back to the panel and the whole system maybe double check the gnd rod as well; So if the breaker was replaced with a NEW breaker (UBI Mfg) the breaker should trip upon a short
FPE Breakers have a nasty history; There are contractors who will cut a piece of NMB so they can keep doing the demo and go back to fix it later only to have the cutters completly trashed; FPE (was)is very popular out here; Was the breaker an old wide one where the amp number is the same color as the handle? (probably an old [pre1984]breaker) I was talking to someone who did some research into FPE and it was discovered that the old style did not have a thermal strip in order to open the circuit, so it is not impossible to draw 45amps on a 15 amp breaker and it still will not trip; As far as the shock that was recived it sounds to me that the grounding system is in place and the breaker was feeding the voltage through the gnd wire back to the panel and the whole system maybe double check the gnd rod as well; So if the breaker was replaced with a NEW breaker (UBI Mfg) the breaker should trip upon a short
- Location
- Illinois
- Occupation
- retired electrician
Re: FPE breaker
Rusty,
I'm aware of the past problems with FPE breakers, but I still don't think that this is a breaker issue, there is a problem in the wiring of this system.
Don
Rusty,
Assuming that the receptacle where the voltage was measured between the water pipe and the grounded conductor is not on the faulted circuit, then there should be very little voltage between the water system and the grounded conductor in a code compliant installation. The water pipe and the grounded conductor are required to be bonded together and there should not be voltage between them even under fault conditions. There could be voltage between anything connected to the electrical grounding system and the earth at any location more than a few feet away from the grounding electrode, but there should not be voltage between the water pipe and the grounded conductor at this receptacle. You will read voltage between the conductor that is actually carrying the fault current at other items that are electrically bonded to the system. This voltage would be equal to the voltage drop on the fault clearing conductor caused by the fault current. Even if the water piping was not bonded as required by the code, the voltage between the water system and the grounded conductor would equal the voltage drop caused by the fault current flowing on the service grounded conductor from the utility transformer and the service panel neutral bus. It is very very unlikely that a fault on a #12 NM branch circuit could cause enough current to flow to create an 80 volt drop on the service grounded conductor.
I'm aware of the past problems with FPE breakers, but I still don't think that this is a breaker issue, there is a problem in the wiring of this system.
Don
Re: FPE breaker
Don I respect your opinion 1000 times over but I have to agree with Rusty on this one, and it was an old style breaker with orange paint on the handle you know which ones I'm talking about, and Rus it is very interesting about the thermal strip, perhaps someone has more info about this, and yes old style FPE breakers will not trip even when the circuit goes to ground as I can be a wittness to that.
Don I respect your opinion 1000 times over but I have to agree with Rusty on this one, and it was an old style breaker with orange paint on the handle you know which ones I'm talking about, and Rus it is very interesting about the thermal strip, perhaps someone has more info about this, and yes old style FPE breakers will not trip even when the circuit goes to ground as I can be a wittness to that.
- Location
- Illinois
- Occupation
- retired electrician
Re: FPE breaker
jro,
Explain to me exactly how you can have 80 volts from a neutral that is not part of the faulted branch circuit to the water pipe in a code compliant installation. I don't believe it is possible and it has nothing to do with the OCPD. There is a wiring problem in this installation that cannot be cured by replacing the breaker panel.
Now if you tell me that the neutral at the receptacle is on the the faulted circuit and between the fault and the panel, and that the fault was hot to neutral, then this voltage reading may be possible because it would represent the voltage drop in the neutral caused by the fault current.
Don
jro,
Explain to me exactly how you can have 80 volts from a neutral that is not part of the faulted branch circuit to the water pipe in a code compliant installation. I don't believe it is possible and it has nothing to do with the OCPD. There is a wiring problem in this installation that cannot be cured by replacing the breaker panel.
Now if you tell me that the neutral at the receptacle is on the the faulted circuit and between the fault and the panel, and that the fault was hot to neutral, then this voltage reading may be possible because it would represent the voltage drop in the neutral caused by the fault current.
Don
Re: FPE breaker
First you explain to me how a hot can go to ground and not trip the FPE breaker and not just on this ocassion, as I stated when I arrived the 80v were no longer present, at closer inspection of the wires the ground looked as if it had been used to weld with, after repairing the romex, testing from hot to nuetral and hot to ground the circuit was ok, I'm not a rocket scientist just an master electrician that has 21 years of residential, commercial, and industrial experience and who has seen some odd things when it comes to electricity, and as I stated I respect your opinion, but the FPE breakers have been known to not trip when a fault occures, I will do some research on these breakers and see what I can come up with, any way have a great weekend
First you explain to me how a hot can go to ground and not trip the FPE breaker and not just on this ocassion, as I stated when I arrived the 80v were no longer present, at closer inspection of the wires the ground looked as if it had been used to weld with, after repairing the romex, testing from hot to nuetral and hot to ground the circuit was ok, I'm not a rocket scientist just an master electrician that has 21 years of residential, commercial, and industrial experience and who has seen some odd things when it comes to electricity, and as I stated I respect your opinion, but the FPE breakers have been known to not trip when a fault occures, I will do some research on these breakers and see what I can come up with, any way have a great weekend
Re: FPE breaker
I think a telling factor here is that the only person who read out the mentionedd 80vac was a plumber with a meter, and not the responding electrician. A little operator-error may well be in evidence.
However, I would thoroughly inspect the grounding system in this case, and any excuse to get one more Federal panel out of this world is a good one, in my book. May they all rot soundly in hell with the Zinsco's and the Push-a-matics.
I think a telling factor here is that the only person who read out the mentionedd 80vac was a plumber with a meter, and not the responding electrician. A little operator-error may well be in evidence.
However, I would thoroughly inspect the grounding system in this case, and any excuse to get one more Federal panel out of this world is a good one, in my book. May they all rot soundly in hell with the Zinsco's and the Push-a-matics.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: FPE breaker
Jro even if the branch breaker didn't trip the main breaker or fuses should of.
with that said. I have to agree with you on the possibility that the branch breaker might not of tripped from being faulty but the fact that the main OCP didn't trip seems to say that there was some high impedance in the circuit somewhere.
and it sounds like it was in the neutral circuit just with the response of there was 80 volts between the water pipe and neutral.
for the neutral to rise to that amount of voltage would of ether required a large amount of current on the neutral if in-fact this was a different circuit and the measured volts reflected the voltage on the neutral at the panel. or this measurement was from the same shorted circuit and was just the voltage drop within the circuit.
now the other thing is if the neutral at the panel is not bonded to the grounding and the only bond is the water pipes then it would of been the water pipes that rose to the 80 volts above ground. but with a little checking it would be easy to see which one happened. but if they did have a weak neutral it might of welded it self back to a good connection which could fail at a latter time and would be very dangerous. one thing to remember is if you have a short and it is of a low impedance it will burn the wire from one end to the other not just in one place and to get 80 volts on ether the neutral or grounding would of took more current than the branch circuit would withstand for it to last long enough for the home owner to have the time to get his meter and measure it, the wire would of been gone not just burned at the damage point this is why Don and I do think there is more than what it seems as there has to be a high impedance for this to happen. and the only way for that is one of a few things.
1. The grounding
2. The neutral connection's (including at the pole)
3. The bond from neutral to the grounding bar (A must for the path of the fault current)
4. If the water bond was the only bond for the grounds
I too held a Master (the state i'm in now dont have any). and I have been in this line of work since 1976. and when I was in school grounding was one of the major areas that I was in but it was mainly lightning protection. but I do have a good understanding of grounding and understand what happens under high current connections and how easily they fail with the smallest increase of current.
Jro even if the branch breaker didn't trip the main breaker or fuses should of.
with that said. I have to agree with you on the possibility that the branch breaker might not of tripped from being faulty but the fact that the main OCP didn't trip seems to say that there was some high impedance in the circuit somewhere.
and it sounds like it was in the neutral circuit just with the response of there was 80 volts between the water pipe and neutral.
for the neutral to rise to that amount of voltage would of ether required a large amount of current on the neutral if in-fact this was a different circuit and the measured volts reflected the voltage on the neutral at the panel. or this measurement was from the same shorted circuit and was just the voltage drop within the circuit.
now the other thing is if the neutral at the panel is not bonded to the grounding and the only bond is the water pipes then it would of been the water pipes that rose to the 80 volts above ground. but with a little checking it would be easy to see which one happened. but if they did have a weak neutral it might of welded it self back to a good connection which could fail at a latter time and would be very dangerous. one thing to remember is if you have a short and it is of a low impedance it will burn the wire from one end to the other not just in one place and to get 80 volts on ether the neutral or grounding would of took more current than the branch circuit would withstand for it to last long enough for the home owner to have the time to get his meter and measure it, the wire would of been gone not just burned at the damage point this is why Don and I do think there is more than what it seems as there has to be a high impedance for this to happen. and the only way for that is one of a few things.
1. The grounding
2. The neutral connection's (including at the pole)
3. The bond from neutral to the grounding bar (A must for the path of the fault current)
4. If the water bond was the only bond for the grounds
I too held a Master (the state i'm in now dont have any). and I have been in this line of work since 1976. and when I was in school grounding was one of the major areas that I was in but it was mainly lightning protection. but I do have a good understanding of grounding and understand what happens under high current connections and how easily they fail with the smallest increase of current.
karl riley
Senior Member
Re: FPE breaker
I think Don and Hurk are right on. The failure of the breaker is a separate problem. The bonding and grounding has to be checked out.
Karl
I think Don and Hurk are right on. The failure of the breaker is a separate problem. The bonding and grounding has to be checked out.
Karl
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: FPE breaker
As previously stated I do not believe that the breaker is the problem.
Chances are that the nail cut the neutral and made a neutral to ground connection. I'll bet the cause of the problem was removed before you got there.
Karl
If you have not, can either you or Mike write a book called "Grounding and Bonding for Dumbies". No offense to anyone.
I understand what you and others write, however I can not put it to the pen.
Mike P.
[ May 25, 2003, 12:02 AM: Message edited by: jxofaltrds ]
As previously stated I do not believe that the breaker is the problem.
Chances are that the nail cut the neutral and made a neutral to ground connection. I'll bet the cause of the problem was removed before you got there.
Karl
If you have not, can either you or Mike write a book called "Grounding and Bonding for Dumbies". No offense to anyone.
I understand what you and others write, however I can not put it to the pen.
Mike P.
[ May 25, 2003, 12:02 AM: Message edited by: jxofaltrds ]
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