Monitoring tripped GFCI

[tmbrown97]

(Does RIB make a double relay in a box? )

Why yes they do. That unit, if wired at the GFCI itself, could be hooked up to the power before and after the GFCI.

If you didn't want to bother with rules and separate inputs, but wanted to avoid alerts related to lost power, there's a way you could wire a single set of contacts through both relays - where, when AC is on, if GFCI trips, it opens the circuit; but if power is lost, it bypasses the GFCI monitor and closes the circuit anyways. There may be an extremely brief state change, but most likely it'd be too fast for the panel to notice.

 

[N49atv]

The above recommendations will work. If you wire a 120V coil into the downstream side of the GFCI, you will lose your dry contacts when it trips (use NO contacts). This can be done with a very cheap, robust relay. I would keep the coil 120V, and not xform it down. Here is why...

Relays have Drop out voltages. Once a relay is energized, if the voltage is slowly lowered, it will eventually turn off when the voltage is too low. This is much lower then its pull in (slowly increasing till relay contacts switch). at 120V there is a much more forgiving drop out voltage, so little blips shouldnt effect it as much as dropping from say 12V to 7V etc. Going from 120 to 100 etc, wont cause it to drop out. I seem to recall around half of the coil voltage from school. You would need a substanial brown out (storm etc) to get it to drop out.

Im not sure of programming capabilities, however in my work (oilfield electrical), we put what we call a D-Bounce on a lot of I/O. This is a delay, where the input has to toggle for more then a set amount of time before alarming or shutting down. We use this a lot on tank levels. If a tank is being filled, etc, and the liquid is sloshing around, it could hit the high level switch. This would trip it thinking the tank is full, when in fact its just the motion of the water splashing against it, and its really only 1/2 or 2/3 full. We generally put a 5-10sec delay on it, to make sure its actually tripped. This would work in this situation.

Hopefully you can pull wire to the plug you want to monitor.

 

[tmbrown97]

The suggested RIB is like $15, and is in a format that integrates very nicely into existing wiring. Sure you could get creative with a 120V relay if you know how, but it'll never look as clean or be as code-compliant.

 

[znelbok]

Wiring practices here are a little different. It appears a GFCI and a RCD are the same thing - they detect an imbalance in electrical flow between the hot and the neutral (In the US we only have 1 hot wire). We can do this in the breaker box with just a larger special GFCI breaker, or we can do it with an device placed somewhere along the circuit, such as those leviton outlets linked above. Once a GFCI outlet is placed on a circuit, anything wired downstream from it is protected by it as well. Our plugs don't have piggyback plugs; they have screw terminals. On a GFCI, the top set is the incoming power, and the bottom set is the downstream; but from there, what we're talking about is basically the same thing - wiring that RIB into the downstream somewhere, which is just a 120V relay in a nice package.

Same but different. We also have outlets with RCD's built in, but they are not to be used in new installations - the whole circuit must be protected.

Out RCD's look like a circuit breaker (well they are a combined circuit breaker and RCD together)

You then mount the auxillary contact block on the side of the RCD. This can be used with your monitoring system (say M1). Its just a dry contact closure. This won't dalse trigger on a power loss as the RCD does not trip. It will only trip on a ground fault or an over current. I use them on a couple of circuits (such as the circuit the fridge is on) and get alerts so I know I have a fridge with no power.

As for the piggy back plug, this is what I have used. Its just a sstandard side entry plug that allows a second plug to be inserted on the back of it
I use it with a relay (240vAC in my case) to tell me if the power is on or off. It means there is no modification to the original circuit. This is on a pump that is controlled by a float switch. It was the easiest way to detect if the pump was running or not.

This is not obviously going to help anyone here as you are predominately US, but I hope it shows the differences and may spark some out of the box thinking.

Mick