Wiring questions:

[LCZ]

In my kitchen above the counter are three receptacles. The other day the first receptacle (far left) got hot an showed 'serious' melting an burn damage. When facing the wall the circuit runs left to right. These three receptacles are all that is on this circuit. Circuit is on a 20 amp breaker. Wiring is 12-2. We had the coffee maker running as always on the 3rd (far right) receptacle. The far left is NEVER used because of it's location. My wife had just used the center receptacle to plug in a griddle and made pancakes. Both coffee maker and griddle are less then a year old and show no damage. A few year ago we remolded our kitchen and I had these receptacles replaced. THEY WERE THE WRONG TYPE. The receptacles are standard 15 amp type not 20 amp as they should have been. In replacing them today I found that the center receptacle also was seriously burned where the hot (black) wire was connected. Here's my questions: The source was wired into the top of the first receptacle and then another wire from the bottom on to the second (center) receptacle and then the same on to the last. (a) Doesn't this cause the entire load of the circuit to be pulled 'through' this one receptacle? If I put the leads from the source and the leads to the center receptacle together and run a pigtail to the receptacle would this prevent the receptacle itself from carrying the entire load of the circuit? The center receptial was wired the same way thus it way carrying the full load for itself and the last receptacle. The first receptacle was a complete meltdown. Even though a 15 amp receptacle was on a 20 amp circuit I would not have expected this kind of damage. I would have expected the breaker to trip first. Especially since this circuit has been in this configuration for years. Should I suspect that the breaker failed and replace it also?

[Jeff Wisnia]

You are correct. It was prolly a cheap receptical or perhaps the wires were connected through those "back stab" holes, which often fail to make a tight connection. Much better to always capture the wires under a firmly tightened screw head or under a screwed clamp (on newer design recepticals.) If you do use pigtails then make sure the pigtail splices are well made.

Not unless it's NOT a GFCI breaker already. If it isn't, do your family a favor and swap one in. AFAIK it's a code requirement for kitchen outlets now.

It might also be a good idea to check around and buy "better quality" 20 amp recepticals. As with most things you get what you pay for (Hopefully most of the time.) Prolly "industrial grade" could be a wise investment.

HTH,

Jeff

[RBM]

First of all, the NEC requires all kitchen counter outlets to be GFCI protected. Second, although the receptacle was not 20 amp, the feed through is rated for 20 amp. Yes, all the current is being pulled through each receptacle when wired that way and any connection that is not tight will cause a problem like yours. The best remedy is to pigtail the wires at each outlet with tails to each receptacle

[jim_duprey]

First, since it is a kitchen counter I'd reccomend putting in GFCI receptacles and be sure any units in series are protected. Next, determine the expected load of the entire circuit. Series wired outlets are safe as long as the load rating isn't exceeded, which it appears happened in your case. I'd seriously consider putting individual breakers on each of the heavily loaded outlets. As an example, a microwave oven on a kitchen counter should have a dedicated circuit breaker and a GFCI at the outlet. Many kitchen appliances use heating elements, which are a heavy load item. Have an electrician add a piggyback box onto the main if all the breaker slots are already taken and additional breakers are needed.

It sounds like you already used up a heavy dose of luck and cashed in on some karma from the good Lord in avoiding an electrical fire. Don't skimp, and hire a pro wherever you're at all unsure about what's needed.

[Doug Miller]

This is not a problem in and of itself -- the electrical code permits use of

15 amp receptacles on 20 amp circuits.

Yes, it does. If the receptacle is rated for a 20-amp feed-through, that's not a problem -- but it rather appears that yours were not. Or, if they were, they shouldn't have been :-)

Correct.

Pigtail that one too.

Why would you expect the breaker to trip? Was the load in excess of 20 amps? A

19-amp load, particularly over an extended period of time, is likely to damage a 15-amp receptacle -- but it won't trip a 20-amp breaker.

Unless you have reason to think that the load imposed was more than 20 amps, there's no reason to think there's a problem with the breaker. On the other hand, your peace of mind is worth something, too, and breakers are cheap.

While you're at it, replace the first receptacle in the chain with a GFCI, and wire it so that it protects the others as well.

[Phisherman]

It doesn't matter where the wire is attached to the receptacle; ie, you can use any of the screws. A tight connection is very important.

If I put the leads from the source

You can make the connection this way, although I prefer to avoid a pigtail unless there is no other way.

Perhaps. You can press the reset button. Make sure all connections are tight, and check that the hot (black) wire is connected to the smaller slot of the receptacle. Better yet, purchase a plug-in tester--they not expensive and you can test all receptacles for ground and proper polarity.

I have a friend that was in the home insurance industry. He stated that (outside of careless cigarette smoking) small appliances are a major cause of house fires.

[Bud--]

All 15A receptacles (that are UL listed) are rated for 20A feedthrough. All 15A duplex receptacles are also rated for a total of 20A draw from the combination of both the outlets.

I generally like pigtailing too.

You could add up the wattages and figure out what the amp draw was. A

20A breaker with a 25A load will take some time to trip. But receptacles are, IIRC, tested at 150% of their rated load. If the connection to a receptacle is loose it produces heat, which makes the connection looser - and hotter, .... Like Jeff (and everyone else) I also don't like back-stab connections.

bud--

[LCZ]

First, thanks to everyone for their information.

In checking the griddle I found it is listed at 1800 W. So if I do my math correctly, on normal household voltage it should pull 15A. (1800/120). The coffee maker which was actually making coffee at the time the circut got hot, vs just keeping the coffee warm, is listed as 800W and 7A. So there should have been about 22 Amps being pulled at one time.

Of course I can be sure all the damage happened at the one time.

What is the tolerance on a breaker? What does it take on average to trip a

20A breaker? It appears that 22 amps ( a + 10%) did not do it..

ANOTHER QUESTION:

Most of you have recommended a GFI be put on this circuit. Back in the 70's I worked in the mining industry, we were required to put GFI protection on all electrical equipment.

We were told that GFI or Ground Fault Interrupt would prevent the equipment from becoming energized when / if it lost grounding. So you had breakers to protect the circuit from over loading and the GFI would knock the circut if the circuit became 'ungrounded'.

So what exactly does a GFI protect you from? What trips a GFI, current over load, voltage overload, or what?

Thanks again to everyone !

[Bud--]

You can buy switch and outlet combinations that fit into a standard outlet cover. One white from the wirenut gets added to the wirenut and goes to the silver screw on the outlet. The black FEED wire goes to the outlet AND switch. The supply black wire goes to the light controlled by the switch.

Mark

[Doug Miller]

For devices currently on the market, yes. I don't think that's always been the case, though.

[Stan]

And thereby, hopefully, trips, to protect you from being electrocuted.

[Bud--]

I would be surprised if anything made since 20A circuits became common (must be over 50 years) wasn't rated 20A feedthrough. Once 15A receptacles started to be installed on 20A circuits it would be apparent to UL that they would be wired as 20A feedthrough. And I suspect it would be hard to make a receptacle that wouldn't safely pass 20A through side-screw terminals; there isn't all that much metal there with 20A feedthrough.

bud--

[Chris Lewis]

According to LCZ :

Not really. The previous "damage" may have been minor or only of short duration, and only the 22A caused it to heat/oxidize fast enough for you to notice.

I should also point out that the 22A is the _maximum_ those devices would pull under standard conditions (temperature, highest allowable circuit voltage etc). They're actually _unlikely_ to be drawing that much.

I would assume that the connections were originally poor, became corroded for some reason, or they were using backstab connections. And the high amp draw was simply the first time it did something obvious enough to notice.

Many years ago, I installed a 12A (max) A/C on a 15A circuit at my parents. The circuit was about 15 years old at that time, and had never had a big load on it before.

_All_three_ outlets between the A/C and the panel smoked, despite the circuit _not_ being overloaded.

Backstab connectors. On Aluminum.

[Every connection failure I've ever seen has been backstab, aluminum or both.]

[CAS]

Neither of the above. GFIs cut power if there's a "ground fault", which means that some of the current is flowing to ground, instead of just between hot and neutral. GFIs provide some protection from electric shock by cutting off current in the event that YOU become a path to ground. So code requires them in places that are likely to be wet, as that makes you a better route to ground. (In basic terms, they work by making sure there's no difference between current on hot and neutral legs. They can work even for old, ungrounded wiring, although an outlet tester won't detect that they're working.)

Worth mentioning that GFIs don't protect you from all shocks. If you manage to position yourself so that you are the route between the hot and the neutral, and you're not grounded at the time (maybe you're wearing sneakers?), current will flow through you without triggering the GFI.

[JGolan]

[bowgus]

In this part of the world (Canada, Ontario), code is that over the kitchen counter, each receptacle is split and wired such that each side is wired to it's own 20A breaker. Makes for a safer kitchen since most appliances are at least 15A.

[Calvin Henry-Cotnam]

Not quite.

The Ontario Electrical Safety Code states that kitchen counter receptacles must be EITHER 15A split OR 20 A not split. The allowance for 20 A non-split was added a couple of years ago when GFCI became manditory for kitchen outlets within 1 metre (39") of a sink.

You may wire up to TWO outlets to the same breaker, provided they are not the next outlet down the counter from each other (i.e.: the two on the same circuit must be separated by another outlet on another circuit).

[bowgus]

Oops ... but on the practical side, just had my old house rewired. The electrician recommended 20A split and that made sense to me ... e.g. microwave oven, who knows what else gets plugged in in future.

OT: I myself don't mind overdesign especially when the additional cost was basically zero and the existing panel etc was more than adequate.

[Doug Miller]

If the current doesn't go to neutral or to ground, where else is it going?

[Mark Lloyd]

How about a short from the hot side of the GFCI output (load) to the neutral side of the GFCI input (line)? That's how some GFCI "test" buttons work.