GFCI spa disconnect how it trips ?

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ritelec

ritelec

Senior Member
Location
Jersey
Hello,
I re-fed a spa disconnect today,

I'm not sure of the make, but I was on my belly, it's in an awkward spot, I started getting rained on and I needed to get out of there to pick up the mrs.

So I was unable to figure it out.

I turned on the breaker at the panel. Checked for voltage at the disconnect and then the 240v pump receptacle and 120v receptacle. All good.

Check hot to ground on both the 120v receptacle and the 240v receptacle. It did trip the gfci in the enclosure that goes to the contactor.

How did it trip when I tested the 240v leg to ground?

I google and was able to find this (sure looks like the unit), but can't find the schematic.

The exterior is what it looked like with the cover closed, but if you opened the door it looked like the guts in the picture I supplied.
The disconnect is pull out.

May I add, Is this permissible for a pool pump? A 240v circuit feed through a contactor fed from a 120v gfci (again I don't know how it works if thats what it's doing)


Thank you.
 
It appears that the GFCI is there only to give the appearance of GFCI protection.
It is in the coil circuit of the contactor only, which means that "testing" it will turn off the pump, but you are not actually getting any GFCI protection for the pump circuit.
But by putting a low impedance meter between either 240V leg and the GFCI neutral you would be imbalancing that GFCI because the hot is not going out through that GFCI.
Now how does a current to ground instead of neutral affect this? Well, I would suspect that there is an extra ground-neutral bond is play somewhere too.

Without a wiring diagram, I will stand by my SWAG above.
 
ritelec said:
Hello,
I re-fed a spa disconnect today,

I'm not sure of the make, but I was on my belly, it's in an awkward spot, I started getting rained on and I needed to get out of there to pick up the mrs.

So I was unable to figure it out.

I turned on the breaker at the panel. Checked for voltage at the disconnect and then the 240v pump receptacle and 120v receptacle. All good.

Check hot to ground on both the 120v receptacle and the 240v receptacle. It did trip the gfci in the enclosure that goes to the contactor.

How did it trip when I tested the 240v leg to ground?

I google and was able to find this (sure looks like the unit), but can't find the schematic.

The exterior is what it looked like with the cover closed, but if you opened the door it looked like the guts in the picture I supplied.
The disconnect is pull out.

May I add, Is this permissible for a pool pump? A 240v circuit feed through a contactor fed from a 120v gfci (again I don't know how it works if thats what it's doing)


Thank you.
Click to expand...

IMO, When you tested between hot and ground, the current through the tester was more than 5mA. A 240V GFCI monitors the current imbalance in the two hot conductors. What kind of tester was used?? A DMM shouldnt cause a GFCI trip but a wiggy or vol-con could....:)
 
Yes, I used a wiggy.
Ok, I can see now how it would have tripped returning path back through the neutral.

Is this legal, and worthy of protecting fulfilling gfci requirements for 240v motors (pool or spa)?

I went there today, and this was the only info. again, it's in a bad spot but, unless they make a two pole blank (dead) front gfci, it would appear to be wired as you described at 120v controlling the coil.

This is it.

http://www.connecticut-electric.com/TechDocs/SpaPanels/8-04SPA250 Owner Manual.pdf

thank you
 
Do the conductors pass through a CT, perhaps located behind the GFCI device? Is that a typical "blank face" GFCI or is it something different.

My guess is this is arranged to GFCI protect everything supplied from it, it just happens to have a secondary 20 amp 120 volt protected circuit. The GFCI device is not designed to handle 60 amps (which was the rating of the assembly according to labeling on the package) but it still monitors conductor currents for leakage and interrupts the circuit with an external contactor when necessary.


Add: What I describe is what your typical 15/20 amp GFCI receptacle or "dead front" GFCI does anyway, it just has smaller components and they are contained within the assembly, this one being higher amperage likely just put the CT and contactor outside the assembly containing the logic components.
 
Last edited:
The two problems I have with the wiring diagram are:
1. It implies that the dead front GFCI is in fact 240 two pole 3-wire. Can you confirm this?
2. It does not show the coil wiring of the contactor but instead implies that the 3-pole contactor is interrupting the neutral too. That may be allowed but is IMHO a bad idea.

Tapatalk!
 
GoldDigger said:
The two problems I have with the wiring diagram are:
1. It implies that the dead front GFCI is in fact 240 two pole 3-wire. Can you confirm this?
2. It does not show the coil wiring of the contactor but instead implies that the 3-pole contactor is interrupting the neutral too. That may be allowed but is IMHO a bad idea.

Tapatalk!
Click to expand...
I'm pretty certain I have seen something similar to this before. That contactor is opening all circuit conductors when the GFCI trips, they just did a poor job of showing how it works. There about has to be a CT involved, probably on the backside of the "GFCI" device, and all the "main" conductors pass through it. Interrupting the neutral is common and maybe even a requirement for GFCI protection. After all if the neutral is carrying the unbalance current because of a neutral-ground fault, you would want to interrupt it when you trip.
 
Thank you for the responses.

I found this.

http://forums.mikeholt.com/showthread.php?t=108166

It's mentioned "all" the conductors go through a ct ???

It also sends you to a link. I think for the 260, I think this one with the dead front is the 250, kinda what the op in the other thread mentions of wiring but relates.

The link shows the conn. elec. new design that to me looks like a 4 pole main lug disconnect with a 2 pole gfci breaker and a regular single pole breaker (guess that single pole circs not gfci protected and you would have to install a gfci receptacle).

I'm curious about the pull out with dead front model and will get in touch with them this week. Just curious. I'll let you know if I find out anything interesting .
 
ritelec said:
I'm curious about the pull out with dead front model and will get in touch with them this week. Just curious. I'll let you know if I find out anything interesting .
Click to expand...

Nothing to be curious about IMO. It appears the unit is prewired from: the top of the pull-out to the GFCI, from the GFCI to the contactor, contactor to the 15A breaker, and from the neutral bar to the contactor.

When you pull out the "pull-out" :))) it disconnects the line side from the load side. Everything is dead, including the dead front!:D

Only field wiring is your line feed, load to spa, and load to branch circuit. The disconnect isolates all the power when pulled out.
 
Little Bill said:
Nothing to be curious about IMO. It appears the unit is prewired from: the top of the pull-out to the GFCI, from the GFCI to the contactor, contactor to the 15A breaker, and from the neutral bar to the contactor.

When you pull out the "pull-out" :))) it disconnects the line side from the load side. Everything is dead, including the dead front!:D

Only field wiring is your line feed, load to spa, and load to branch circuit. The disconnect isolates all the power when pulled out.
Click to expand...

Ok. Not very interesting.
I understand what your saying but don't understand how it trips to ground. With the one ct.

Wait. Maybe I do

I may be off but.

If all is good. There's a canceling out between leg to leg or leg to neutral. Which should be zero. If things aren't good the ct picks up the amperage going to ground ??


The gfi is fed line load as normal to the contractor coil.
And the ct is wired in series on load side.


Do I have it?
 
ritelec said:
Ok. Not very interesting.
I understand what your saying but don't understand how it trips to ground. With the one ct.

Wait. Maybe I do

I may be off but.

If all is good. There's a canceling out between leg to leg or leg to neutral. Which should be zero. If things aren't good the ct picks up the amperage going to ground ??


The gfi is fed line load as normal to the contractor coil.
And the ct is wired in series on load side.


Do I have it?
Click to expand...
I think you got it. Even your standard 15/20 amp GFCI receptacle only has one CT, with all monitored circuit conductors running through it. If load in is equal to load out there is no voltage developed in the CT. It is when there is a ground fault that the load in is not equal to load out and a voltage is developed in the CT and triggers the trip circuitry.
 
ritelec said:
Ok. Not very interesting.
I understand what your saying but don't understand how it trips to ground. With the one ct.

Wait. Maybe I do

I may be off but.

If all is good. There's a canceling out between leg to leg or leg to neutral. Which should be zero. If things aren't good the ct picks up the amperage going to ground ??


The gfi is fed line load as normal to the contractor coil.
And the ct is wired in series on load side.


Do I have it?
Click to expand...

I think you do. It looks like they're pulling power to the GFCI from the red line side of the contactor plus a neutral, then powering the contactor from the load side of the GFCI (this isn't shown on the "schematic"). If there is an external CT (there would have to be for this to work) then yeah, it would sense the imbalance when current leaked to ground and trip the GFCI.
 
PetrosA said:
I think you do. It looks like they're pulling power to the GFCI from the red line side of the contactor plus a neutral, then powering the contactor from the load side of the GFCI (this isn't shown on the "schematic"). If there is an external CT (there would have to be for this to work) then yeah, it would sense the imbalance when current leaked to ground and trip the GFCI.
Click to expand...

From what I saw/read of this, all the power goes through the GFCI. The CT is integral to the GFCI.
 
Little Bill said:
From what I saw/read of this, all the power goes through the GFCI. The CT is integral to the GFCI.
Click to expand...
The only unresolved question, although one can make a good guess from the photo, is whether the line wires go to and from screw terminals at the back of the GFCI or just pass unbroken through the hole of a CT.

Tapatalk!
 
This is a pretty common type of Spa disconnect in my area. I have never used them though. The price is not much different that a GFCI circuit breaker with enclosure and the onces I have run across are sometime loud since the contactor is on 24/7.

Here is a picture of the GFCI used. The wiring diagram posted by the OP doesn't show all of the wiring.
ibcGetAttachment.jsp.jpg
The GFCI gets wired like a normal GFCI but it only feeds the coil of the contactor. It does not monitor the line and load terminals for imbalance. It only monitors the conductors running through the CT. If it detects an imbalance it opens the load wires connected to the GFCI which open the coil.
 
GoldDigger said:
The only unresolved question, although one can make a good guess from the photo, is whether the line wires go to and from screw terminals at the back of the GFCI or just pass unbroken through the hole of a CT.

Tapatalk!
Click to expand...

curt swartz said:
This is a pretty common type of Spa disconnect in my area. I have never used them though. The price is not much different that a GFCI circuit breaker with enclosure and the onces I have run across are sometime loud since the contactor is on 24/7.

Here is a picture of the GFCI used. The wiring diagram posted by the OP doesn't show all of the wiring.
View attachment 10488
The GFCI gets wired like a normal GFCI but it only feeds the coil of the contactor. It does not monitor the line and load terminals for imbalance. It only monitors the conductors running through the CT. If it detects an imbalance it opens the load wires connected to the GFCI which open the coil.
Click to expand...


Found this from another thread:

I was looking over a Connecticut Electric spa panel and noticed not a gfci breaker but instead just a blank faced gfci, the pull out and 15a breaker. I opened it up and saw that the line comes in and is routed through a ct which is mounted/integral to the gfci, then into a four pole contactor.
Click to expand...
 
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