240 volt gfci

Status
Not open for further replies.
Steve Brady said:
can someone explain how a 240 volt gfci circuit breaker is going to work on a pump motor for a swimming pool?
Click to expand...

Perfectly? :smile:

There is no reason why it would not, you will still have to land the neutral from the breaker onto the neutral bar for it to operate.
 
Like in a 120 volt GFCI breaker it will monitor the current flowing through the circuit conductors. If there is a current imbalance between 4-6 ma or larger it will trip the CB.
 
stickboy1375 said:
Not directed at the OP, but anyone want to guess why this question is a hard one? And is asked quite often.
Click to expand...

My guess is that the confusion stems from the fact that you can't use 2 single pole GFCI CB's on a MWBC which is sharing a neutral. You certainly could use a 3-wire circuit with a 2 pole GFCI CB.
 
misunderstanding the question

misunderstanding the question

the pool pump operates at 240 volts, no neutral on the pump , currents flow from the cb to device the gfci will monitor the current supplied but will not monitor the return currents on the neutral so the question still is how will someone have gfci protection on the pool pump motor (required)
 
Steve Brady said:
the pool pump operates at 240 volts, no neutral on the pump , currents flow from the cb to device the gfci will monitor the current supplied but will not monitor the return currents on the neutral so the question still is how will someone have gfci protection on the pool pump motor (required)
Click to expand...

How do you know a 240 volt gfci breaker does not monitor both legs for a difference in current? This should be your question.....

"Does a 240v GFCI CB monitor both legs when not using a neutral on the load side?"
 
Steve Brady said:
the pool pump operates at 240 volts, no neutral on the pump , currents flow from the cb to device the gfci will monitor the current supplied but will not monitor the return currents on the neutral so the question still is how will someone have gfci protection on the pool pump motor (required)
Click to expand...

Steve if the pump does not use a neutral to operate the GFCI will not need to monitor current that does not exist.

When a GFCI is protecting a simple 120 volt circuit it monitors the current on the neutral and the hot as long as they are within about 5ma the GFCI will not trip.

When a GFCI is protecting a 240 volt circuit it monitors the current on both hots, as long as they are within about 5ma the GFCI will not trip.

When a GFCI is protecting a 120/240 volt circuit it monitors the current on the neutral and the two hots as long as they are within about 5ma the GFCI will not trip.
 
iwire said:
When a GFCI is protecting a 240 volt circuit it monitors the current on both hots, as long as they are within about 5ma the GFCI will not trip.
Click to expand...

Why does the neutral need to be connected on the breaker if it is only monitoring the current on both legs of a circuit without a neutral load. That may be what the op wants to know. I don't have the answer but it needs to be connected.
 
Dennis Alwon said:
Why does the neutral need to be connected on the breaker if it is only monitoring the current on both legs of a circuit without a neutral load. That may be what the op wants to know. I don't have the answer but it needs to be connected.
Click to expand...


My guess is that the electronics inside the breaker require it.
 
Hey ,.. I just thinking of Andy and his festival gfci issue .. if the 2pole GFCI only had current on one phase could,..that be causing his gfci to trip ....??? just thinking out loud and I know it is the wrong thread ,.. maybe a current is being created in the phase with no load??
 
M. D. said:
Hey ,.. I just thinking of Andy and his festival gfci issue .. if the 2pole GFCI only had current on one phase could,..that be causing his gfci to trip ....??? just thinking out loud and I know it is the wrong thread ,.. maybe a current is being created in the phase with no load??
Click to expand...



If a two pole breaker only has current on one phase he has a serious problem...
 
M. D. said:
Hey ,.. I just thinking of Andy and his festival gfci issue .. if the 2pole GFCI only had current on one phase could,..that be causing his gfci to trip ....??? just thinking out loud and I know it is the wrong thread ,.. maybe a current is being created in the phase with no load??
Click to expand...

If the gfci is feeding a MWBC then would that happen. There would almost always be a difference in current between phases. No?
 
It was this comment that got me to thinking


andy said:
One other item of note that sort of raises a red flag with me is that the manufacturers wiring diagram has all of the modules on one leg of the 240 V circuit (the other leg is used for additional modules on larger systems) and am wondering if this could cause any problems with the gfci tripping. Would an imbalanced load on a 2 pole gfci make it trip? I don't think so, but I'm trying to think of everything.
Click to expand...
 
M. D. said:
Why is that
Click to expand...

MWBC- common neutral--suppose phase A is running a circuit at 13 amps and phase B draws 10 amps. Are you saying that would trip a dp gfci? I thought a dp gfci would work on a MWBC
 
Dennis Alwon said:
If the gfci is feeding a MWBC then would that happen. There would almost always be a difference in current between phases. No?
Click to expand...

If it was feeding a MWBC then to me, any current going out one wire must return on one of the other two, when it does not, then the gfci trips.
 
Dennis Alwon said:
MWBC- common neutral--suppose phase A is running a circuit at 13 amps and phase B draws 10 amps. Are you saying that would trip a dp gfci? I thought a dp gfci would work on a MWBC
Click to expand...


Thats not how it works, Total IN = Total OUT, when there is a difference it trips...
 
Status
Not open for further replies.
Top