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240 V GFCI #127137
05/08/01 03:31 PM
05/08/01 03:31 PM
A
Anonymous OP
Unregistered

Can a two-pole 240 V GFCI detect a ground fault that draws equal amounts of leakage current (e.g., 1.0000 A) from both poles?

[Linked Image]

[This message has been edited by Dspark (edited 05-08-2001).]

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Re: 240 V GFCI #127138
05/08/01 06:32 PM
05/08/01 06:32 PM
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
If you wired it as per the diagram, you'd probably kill someone.

But this was mentioned in the other thread...


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: 240 V GFCI #127139
05/08/01 07:27 PM
05/08/01 07:27 PM
A
Anonymous OP
Unregistered

I'm hoping that Bill fixes the image.
The diagram, I think, will show how the manufacturer wires it.

Re: 240 V GFCI #127140
05/08/01 11:49 PM
05/08/01 11:49 PM
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,901
NY, USA
Wiring Diagram Fixed!

Re: 240 V GFCI #127141
05/09/01 06:21 AM
05/09/01 06:21 AM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,360
ok, thanks Bill...

now can someone explain this??

[Linked Image]

Re: 240 V GFCI #127142
05/09/01 08:50 AM
05/09/01 08:50 AM
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
The way I understand it is that all three conductors pass through the coil, and the current should balance to zero under normal operation. When a fault occurs, there is an imbalance that is detected by the coil and opens the line.

I was thinking before that it would take one coil for each pair (Line "A" to Ground, Line "B" to Ground, Line "A" to Line "B") but I'm mistaken.

As far as getting deeper into how they work... Better let Scott handle it!

[Linked Image]


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: 240 V GFCI #127143
05/09/01 03:23 PM
05/09/01 03:23 PM
A
Anonymous OP
Unregistered

That's right about how it works in a nutshell.

But I am not clear on whether a symmetrical fault to earth would be detected.

Such a fault is improbable in a hot tub. But I want to know whether it would be detected, if, for instance, a 240 V floor outlet were filled with Pepsi causing a symmetrical fault to ground on both poles.

Re: 240 V GFCI #127144
05/09/01 03:37 PM
05/09/01 03:37 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,360
Dspark;
i never heard of a "symetrical fault" , but theoretically, if both conductors climbed the trip curve equally..???>>>

that would be the pepsi challenge [Linked Image]

Re: 240 V GFCI #127145
05/09/01 04:07 PM
05/09/01 04:07 PM
Scott35  Offline

Broom Pusher and
Member
Joined: Oct 2000
Posts: 2,708
Anaheim, CA. USA
Well everyone, if the leakage current to ground was exactly equal from both Ungrounded conductors and at the same time, that would not trip the device!!

It would be similar to someone grabbing both lines [L1 and L2], then getting the ever loved 240 VAC barbeque. The device would not see that as an inbalanced current, so no trip.

Kind of sucks, doesn't it? [Linked Image]

Scott SET


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
Re: 240 V GFCI #127146
05/09/01 05:34 PM
05/09/01 05:34 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,360
yeah, ouch....
but in the practical world, the probability is slim.
So a good point of discussion is the noodle, gotta have it , straight 240V or not right?
[Linked Image]

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