GFI Breaker Question

[hockeyoligist2]

This morning I ran into something strange and dangerous. I had a call about a GFI breaker tripping and shutting down an outside, plug connected piece of equipment. I checked the receptical to ground and had 120 v but to common had nothing. I pulled the box cover and there was no hot going to the gfi. checked the common and it had 45v to ground. The wires were numbered so i found a corresponding number on another (non gfi) breaker where someone had switched the wires, (had to have been done years ago) turned it off and the 45v went away as did the 120 at the receptical. I moved it to the gfi and it quit tripping, amps check ok etc. Shouldn't the gfi have tripped when they made the swap?

 

[kalanjeya]

Re: GFI Breaker Question

I checked the receptical to ground and had 120 v but to common had nothing. I pulled the box cover and there was no hot going to the gfi. checked the common and it had 45v to ground. The wires were numbered so i found a corresponding number on another (non gfi) breaker where someone had switched the wires, (had to have been done years ago) turned it off and the 45v went away as did the 120 at the receptical. I moved it to the gfi and it quit tripping, amps check ok etc. Shouldn't the gfi have tripped when they made the swap?

I am sorry , but u could have explain in little simple way, some of the line unable to understand, u meant common as grounding conductor.

Let me explain,on what i understood, there were short circuit between hot and grounded conductor at GFI protected receptacle(connected through GFI receptacle), and GFI was not tripped off.

GFI would not sence the short circuit current , so it didnot tripped off the circuit.It would sence the deviation / difference of currrent flow at Hot and ground conductor.

I thing i am right , any one have any other explanation ?

Thanks

Kalanjeya

 

[hockeyoligist2]

ok

ok

at the receptacle the ungrounded conductor checked to the bonding ground on the receptacle read 120v. but the ungrounded conductor to the grounded Conductor read 0v (with the machine unplugged) . on the breaker panel the gfi grounded conductor read's 45v to the system ground (with the machine plugged in) (single plug) . the gfi breaker had no ungrounded conductor connected to the breaker, the ungrounded conductor in the circuit was connected to a non gfi breaker.

 

[jim dungar]

Let me try.

The line side of the breaker is connected to the "live" panelboard bus.
The line side white "pig tail" of breaker is connected to the panelboard neutral.

The load "hot" side of the breaker is not to anything.
The load side grounded terminal of the breaker is connected to the grounded terminal of the receptacle.

The "hot" terminal of the receptacle is connected to an ungrounded conductor of a different circuit.

Measurements taken were:
At receptacle without load:
Line to grounded conductor = 0V
Line to grounding conductor = 120V

At the breaker with load connected:
Load side grounded conductor to ground = 45V

Then the circuit rewired so the load side of the breaker was wired to the ungrounded terminal of the receptacle.
Measurements taken were:
At receptacle without load:
Line to grounded conductor = ?V
Line to grounding conductor = 0V

At the breaker with load connected:
Load side grounded conductor to ground = 0V

Is this correct so far?

 

[hockeyoligist2]

The line side of the breaker is connected to the "live" panelboard bus.
The line side white "pig tail" of breaker is connected to the panelboard neutral. yes

The load "hot" side of the breaker is not to anything. no it is connected to another breaker, non gfci
The load side grounded terminal of the breaker is connected to the grounded terminal of the receptacle. yes

The "hot" terminal of the receptacle is connected to an ungrounded conductor of a different circuit. yes

Measurements taken were:
At receptacle without load:
Line to grounded conductor = 0V
Line to grounding conductor = 120V yes

At the breaker with load connected:
Load side grounded conductor to ground = 45V yes

Then the circuit rewired so the load side of the breaker was wired to the ungrounded terminal of the receptacle. yes
Measurements taken were:
At receptacle without load:
Line to grounded conductor = ?V 120
Line to grounding conductor = 0V 120

At the breaker with load connected:
Load side grounded conductor to ground = 0V 120

Is this correct so far? yes