Splicing outdoor extension cords

[Clare Snyder]

Combo AFCI/GFCI breakers???I have a few of those installed in the new panel of our 50 year old house. We have a couple circuits with GFCI outlets - one being where a refrigerator is downstream ( no separate circuit 50 years ago) and not protected - so could not do it with GFCI breaker. The upstairs bedrooms are on AFCI to meet code as it was when the panel was replaced . GFC! protecting edison circuits gets expensive in a Square D QO panel up here in Canada!!!! Thankfully they are all CSA approved so I was able to order them out of the states for less than half price - - -

-including shipping and import fees.

[Jim Joyce]

I don't think there are any combo AFCI/GFCI breakers in my panel. I believe all of them are just GFCI.

What explains the cost difference in CA vs US?

[trader_4]

I think the false tripping of refrigerators with GFCIs is either an urban myth or partly so, perhaps based on eary GFCI and/or old refrigerators. And perhaps those early refrigerators were indeed faulty, with leakage current.

[hubops]

but but .. what if the fridge is in the garage ! huh ..

John T.

[Ralph Mowery]

The code changes all the time as to what is legally required. Just too much government regulations. If I were building a house I might have to put in those GFCIs but they would be replaced with standrd breakers when the inspector finished with the house.

One way the GFCI would trip is on motors or other inductive devices. There is a voltage/current phase difference where the current is delayed just enough from the hot to the neutral wire to trip the GFCI.

[Clare Snyder]

IIRC single outlet "dedicated use" circuits are still GFCI exempt under current code under certain circumstances.

[Clare Snyder]

Nothing that I am aware of other than they can get away with it. I guess they don't sell many "240 volt" 15 amp gfci breakers in Canada????

QO215gfco breakers sell for $235 up here - might get them a bit cheaper from local wholesaler. The QO220 and 230GFCI are a bit easier to get and a few bucks cheaper. I bought the 215gfi units out of the states (new open box) for $75US plus shipping a couple years ago. I can get them for $95 to $115US today - and again the 20 and 30 amp units are easier to get Just checked my panel. I have 2 AFCI breakers, 6 GFCI breakers (4 single and 2 tandem or split), 2 circuits partially protected by GFCI outlets, (at least one has 2 GFCI outlets and at least one unprotected) - then there is the furnace (dedicated 120 volt 15 amp) , AC - (dedicated 220 25 amp), compressor - (dedicated 240 20 amp) Kitchen range (dedicated 240) and dryer (dedicated 240) with no GFCI protection. There is also a full house surge protector and generator interlock infeed breaker leaving 3 open slots in the panel.

[bud--]

gfretwell used to say if a refrig trips a GFCI there is a problem with the refrig.

The current rating on a reftig these days is small. I don't think they have to be on their own circuit. Putting it on with something that would obviously show if the power was off might be good.

If in the US, many should be AFCI. GFCIs were never required 'everywhere'.

[bud--]

So the current in the hot and neutral are not identical? Inductance phase-shifts the current in both the hot and neutral relative to the voltage.

Don't know about Canada.

The NEC used to have exceptions (refrig in garage was probably one). I believe they are all gone now.

[trader_4]

If that's the case, funny that with all the various motors I've had, furnace condensate pumps, shop vacs, grinders, drills, impact wrench, etc it's never happened. The GFCI is looking for the difference in current, not the relationship between voltage and current. Current can't pile up in wire.

[trader_4]

The current rating during normal operation is small. I measured my new full size side by side at about 90W running, 250W when starting. But the big load is the defroster, IDK what those run, but could be 1000W+.

[Ralph Mowery]

It is difficult for me to explain.

When a device that has lots of inductance such as a motor is first turned on it takes time for the current to go through it and get to the neutral. When turned off there is a slight delay before the current quits comming out of the netural. Think of it as a water hose. When the valve at the house is turned on it takes some time for the water to reach the end of a 100 foot hose.

That time delay will cause the GFCI to trip.

[Ralph Mowery]

It could be other things besides the refrigerator. My ham radio will sometimes trip the gfci at my breaker box. Nothing wrong except the gfci is not often designed to work near radio frequency transmitters.

[Clare Snyder]

Recommendations are to NOT protect flourescent light circuits due to "inductive leakage" causing niucance trips and to limit protected circuits to 1 or no more than 2 "appliances". Also protected circuits should be limitted to 100 feet in length to prevent niucance trips. Both capacitive and inductive reactance can cause a sensitive GFCI device to trip. The chances of say, a refrigerator, tripping a GFCI when it is the only device on the circuit is significantly lower than when there are other (particularly inductive or capacitive) loads connected. Motors are inductive and many use capacitive phase shifting to provide high starting torque. Newer refrigerators are less likely than older ones to cause tripping

[bud--]

Think of a hose that starts off full of water. You open the spray nozzle at the far end.

[bud--]

Never heard of that.

Ballasts (and neon sigh transformers) are basically constant current sources. Using "leakage reactance" is a way of making a constant current, and may be what you are talking about.

There is capacitive reactance from hot to ground wire and neutral to ground wire. There is current flow through the reactance. The hot-ground voltage is much higher so the hot-ground current is larger. The longer the cable the higher the inbalance.

Phase shifting is irrelevant. Current going in has to be equal to current coming out unless the device can store a large number of electrons (or 'borrow' a large number of electrons). What is the physics of hot and neutral not being equal?

Is there a problem with large refrigerators in commercial kitchens, which must be GFCI protected?

May well be. Manufacturing standards have probably changed.